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"^ NBS TECHNICAL NOTE 1092

U.S. DEPARTMENT OF COMMERCE / National Bureau of Standards

Design, Evaluation, and Use of a

Reverberation Chamber for

Performing Electromagnetic

Susceptibility/Vulnerability

Measurements

M. L. Crawford

G. H. Koepke

•QC-^

100

.U5753

^ No. 1092

1986
Tm he National Bureau of Standards' was established by an act of Congress on March 3, 1901. The

m Bureau's overall goal is to strengthen and advance the nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a

basis for the nation's physical measurement system, (2) scientific and technological services for industry and

government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety.

The Bureau's technical work is performed by the National Measurement Laboratory, the National

Engineering Laboratory, the Institute for Computer Sciences and Technology, and the Institute for Materials

Science and Engineering.

The National Measurement Laboratory

Provides the national system of physical and chemical measurement;

coordinates the system with measurement systems of other nations and

furnishes essentia] services leading to accurate and uniform physical and

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• Basic Standards'^

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and proposes new engineering practices; and develops and improves

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Conducts research and provides scientific and technical services to aid Federal agencies in the selection, acquisition, application, and use of computer technology to improve effectiveness and economy in Government

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voluntary standardization activities; provides scientific and technological advisory services and assistance to Federal agencies; and provides the technical foundation for computer-related policies of the Federal Government. The Institute consists of the following centers:

Programming Science and

Technology

Computer Systems

Engineering

The Institute for Materials Science and Engineering

Conducts research and provides measurements, data, standards, reference

materials, quantitative understanding and other technical information fundamental to the processing, structure, properties and performance of materials; addresses the scientific basis for new advanced materials technologies; plans

research around cross-country scientific themes such as nondestructive

evaluation and phase diagram development; oversees Bureau-wide technical programs in nuclear reactor radiation research and nondestructive evaluation; and broadly disseminates generic technical information resulting from

its programs. The Institute consists of the following Divisions:

Inorganic Materials Fracture and Deformation'

Polymers

Metallurgy Reactor Radiation

'Headquariers and Laboratories at Gaiihersburg, MD, unless otherwise noted; mailing address Gailhersburg, MD 20899. -Some divisions within the center are located at Boulder, CO 80303. 'Located at Boulder, CO, with some elements at Gaiihersburg, MD.
PISS

CENTER

Design, Evaluation, and Use of a &cidd

Reverberation Chamber for Performing

^^^^^

Electromagnetic Susceptibility/ "^^^^

Vulnerability Measurements

M. L. Crawford

G. H. Koepke

Electromagnetic Fields Division

Center for Electronics and Electrical Engineering

National Bureau of Standards

Boulder, Colorado 80303

Supported in part by

Naval Surface Weapons Centers (NSWC)

Dalgren, Virginia

and

Rome Air Development Center (RADC)

Griffiss Air Force Base

Rome, New York

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Issued April 1986
National Bureau of Standards Technical Note 1092

Natl. Bur. Stand. (U.S.), Tech Note 1092, 146 pages (Apr. 1986)

CODEN:NBTNAE

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1986

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402
FOREWORD

The research described in this report represents the culmination of over 3 years of work

at the National Bureau of Standards (NBS), Electromagnetic Fields Division, Boulder, Colorado,

to carefully evaluate, develop (when necessary), describe, and document the methodology for

performing radiated susceptibility/ vulnerability (EMS/V) measurements using a reverberation

chamber. This effort was jointly funded by the Naval Surface Weapons Center (NSWC), Dahlgren,

Virginia; Rome Air Development Center (RADC), Griff iss Air Force Base, Rome, New York; and the

NBS. Three major tasks were outlined. These were to:

1. Determine how well a shielded enclosure could be made to operate as a reverberation

chamber to establish time averaged (statistically determined), randomly polarized, uniform

EM fields as a function of spatial position, frequency and chamber quality factor (Q);

2. Evaluate interaction effects between the chamber and equipment under test (EUT) placed

inside the chamber to determine:

a. The range of applications of the measurement techniques (i.e., where the technique

could or should not be used),

b. Whether measurement results obtained using the reverberation chamber could be

correlated with results obtained using anecholc chambers or open field sites, and

c. To identify pertinent chamber calibration parameters;

3. Develop a technique applications and use manual.

These tasks were addressed sequentially in three major phases. The first phase was to design, construct, assemble and evaluate an empty (without the presence of an EUT inside)

reverberation chamber with associated instrumentation and software to evaluate its electrical

performance characteristics. This phase of the work began in January 1982 and was completed

by the end of 1983. Results of this effort are contained in Section 2 of this report.

Section 2 discusses the modification of a 2.7^ m x 3-05 m x 4.57 m welded steel shielded

enclosure located at NBS into a reverberation chamber. Information given includes theoretical

concepts, physical design and construction details, and the evaluation of the empty chamber's

electrical parameters. These parameters are excitation and reference receiving antennas

voltage standing wave ratio (VSWR), loss, Q factor, wave impedance, spatial E-field

distribution versus frequency, and determination of the test field level.

The second phase of the work was to evaluate the interaction effects between the chamber

and the EUT placed in the chamber. This effort occupied the latter part of 1983 through 1984.

The results are contained in Section 3 of this report. The third phase was to develop

methodology and evaluate the use of the reverberation chamber for susceptibility measurements

and compare the results to other more conventional measurements techniques such as anechoic

chamoers and to other reverberation chambers. This study included the selection and

susceptibility evaluation of four samples of EUTs: a one centimeter dipole probe, a ridged

horn antenna, a series of rectangular TEM transmission cells with apertures and a modified 7.0 cm (2.75") diameter folded fin aircraft rocket (FEAR). The first three "reference standard"

EUT's were selected because they could be characterized theoretically. The fourth EUT (FFAR) was more typical of an operational EUT which is more indicative of the actual type of

equipment routinely tested for EM susceptibility. Results were obtained for this phase of the

effort during 1984 and 1985. Details of how the measurements were performed, including

setups, approaches, and instrumentation and software requirements are contained in Section 4. The final task was to document these results, presented in Section 5, and to produce a reverberation measurement technique applications and use manual. This, of course, is one of

the purposes of this report. Section 6 gives a brief summary and conclusions drawn from this

study. Some of the more significant are: 1) the NBS chamber lower useful frequency limit is

200 MHz; 2) the spatial variation in the statistically determined E-field established in the

chamber is approximately ± 8 dB at 200 MHz and decreases to ± 2 dB at 2 GHz; 3) the preferred

measurement approaches are mode tuned (explained in section 4.3.2) at frequencies below 2 GHz

and mode stirred (also explained in section 4.3.2) at frequencies above 2 GHz; 4) the loading

effect, of lowering the chamber's Q by inserting the EUT, should be limited to an increase in

chamber loss ^ 6 dB or a minimum tuner effectiveness ^ 20 dB; 5) the average wave Impedance in

the chamber is approximately 1 20it ; 6) the maximum E-field is approximately 7-8 dB greater than

the average E-field established in the chamber; 7) scattering from EUT does not significantly

influence the E-field statistical, spatial distribution; 8) the directional characteristics of

antenna or EUT placed inside the chamber are effectively lost; 9) the response of EUT measured

inside a reverberation chamber is less than when measured inside an anechoic chamber (open

space) in proportion to the EUT open space gain; 10) the response of EUT to an interference
field after it has penetrated the EUT's shield appears to be equivalent in both reverberation

and anechoic chambers; and 11) the experimental error analysis suggests that Root Square Sum

(RSS) errors in establishing the test field inside a reverberation chamber range from

approximately ± 10 dB at 200 MHz to ± M dB at 18 GHz.

Section 7 provides suggestions for future research and Section 8 acknowledges the

significant contribution of others to this project. References cited are given in Section 9.
CONTENTS

Page

Abstract 1

1 . Background and Introduction 1

2. Development of an Operational Reverberation Chamber 2 2.

1

Theoretical Concepts 2 2.2 Physical Design Considerations 5 2.2.1 Chamber Physical Shape and Volume 6 2.2.2 Chamber Quality Factor (Q) 6 2.2.3 Chamber Auxiliary Needs 6 2.2.4 Tuner Design 6 2.2.5 Chamber Excitation and Field Monitoring 7 2.3 Determination of Wave Impedance and E-Field Amplitude Distribution

Inside Reverberation Chamber 8 2.3-1 Determining the Test Field and Wave Impedance Amplitudes 8 2.3.2 Maximum Versus Average Amplitude Responses 9 2.4 Spatial E-Field Distribution 10 2.5 Multiple Excitation of the Chamber 10

3. Interaction Effects Between Chamber, Source and Reference Antennas, and

EUT 11 3.

1

Placement Constraints of EUT 11 3.2 Scattering Effects of Metal Objects Upon E-Field Distribution 11 3.3 Loading Effects of EUT on Chamber 11

h. Performing Immunity Measurements 12

4.1 Planning the Measurements 12 4.2 Measurement Approaches (Tuned vs. Stirred) 14

4. 3 Measurement System 14 4.3.1 Measurement Setup and Instrumentation Requirements 14 4.3.2 Software Requirements and Measurement Procedures 14

5. Experimental Test Results 19 5.1 Correlation of Results to Anechoic Chamber Tests - Some Examples 19 5.1.1 Description of Anechoic Chamber Measurement System 19 5.1.2 Measurement of the Peak Response of a 1 cm Dipole and a Ridged Horn 19 5.1.3 Measurement of RF Coupling Through Apertures in TEM Lines 20 5.1.4 Measurements of the EM Susceptibility of a Modified 7.0 cm Folding Fin Aircraft Rocket (FFAR) 20

5.2 Comparison of Results Between Reverberation Chambers 21

6. Summary and Conclusions 21 6.1 Conclusions Drawn From Study 21 6.2 Summary of Measurement Uncertainties 22 6.2.1 Determining the Field Strength Inside the Chamber 22 6.2.2 General Comments on Error Analysis 24 6.3 Measurement Technique Advantages and Limitations 24

7. Suggestions for Future Research Efforts 25

8. Acknowledgments 26

9. References 26

List of Figures and Tables 28

Appendix 85

Design, Evaluation, and Use of a Reverberation Chamber for Performing

Electromagnetic Susceptibility/Vulnerability Measurements

M.L. Crawford and G.H. Koepke

Electromagnetic Fields Division

National Bureau of Standards

Boulder, Colorado 80303

This report presents the results of work at the National Bureau of Standards,

Boulder, Colorado, to carefully evaluate, document, develop (when necessary), and

describe the methodology for performing radiated susceptibil ity/ vulnerability

measurements using a reverberation chamber. The report describes the reverberation

chamber theory of operation, construction, evaluation, functional operation, and use

for performing immunity measurements. It includes an estimate of measurement

uncertainties derived empirically from test results and from comparisons with

anechoic chamber measurements. Finally, it discusses the limitations and advantages

of the measurement technique to assist potential users in determining the

applicability for this technique to their electromagnetic compatibility (EMC)

measurement needs.

Key Words: electromagnetic susceptibility/ vulnerabil ity ; estimated uncertainty;

evaluation; measurement procedures; reverberation chamber

1 . Background and Introduction

The use of mode tuned or stirred reverberation chambers for performing EMC measurements

is a relatively new method which appears to have considerable potential for electromagnetic

susceptibility/vulnerability testing [1-7]. The idea of reverberating a shielded enclosure as

a way to improve the EMC measurement results obtained using the enclosure was first proposed

in 1958 [1]. Since then measurement procedures have been developed for implementing the

technique for both radiated susceptibility and emission testing, but with considerable

skepticism and a general lack of acceptance on the part of many EMC engineers. Reasons given

include: 1) a lack of information about interaction effects between the EUT, reverberation

chamber, and sources used to excite the chamber, 2) significant unanswered questions

concerning the interpretation and accuracy of the measurement results, and 3) the lack of

clear correlation of test results with other more conventional measurement techniques.

Emphases for performing the work described in this report result from numerous advantages

suggested for use of a reverberation chamber. These include:

1. Electrical isolation from or to the external environment;

2. Accessibility (indoor test facility);

3. The ability to generate high level fields efficiently over large test volumes;

4. Broad frequency coverage;

5. Cost effectiveness;

6. Potential use for both radiated susceptibility and emission testing with minor

instrumentation changes; and

7. No requirement of physical rotations of the equipment under test (EUT).

These advantages are somewhat offset by limitations which include loss of polarization

and directivity information relative to the EMC/EMI profile of the EUT and reduced measurement

accuracy. However, this technique does offers a time efficient, cost effective way to

evaluate EMC performance of large equipment using existing shielded enclosures with only minor

modifications. The concept utilizes the shielded, high-Q, multimoded environment to obtain

uniform (time averaged) fields that may simulate "real world", near field environments.

This report describes efforts to answer some of the questions referred to above and

outlines an approach using this technique for EMS/V testing. It also describes efforts to identify a "correlation factor" between reverberation chamber and anechoic chamber obtained

results, and outlines a detailed, step by step procedure for performing EMS/V tests. An experimental error analysis is given to provide insight into the magnitude of the measurement

uncertainties expected for tests performed using this method.
2. Development of an Operational Reverberation Chamber

2.1 Theoretical Concepts

A reverberation chamber is a large (in terms of wavelength) high quality (Q) cavity whose

boundary conditions are continuously and randomly perturbed by means of a rotating conductive

tuner or stirrer. The time averaged field inside such a cavity, when a sufficient number of

modes are excited, is formed by uniformly distributed plane waves coming from all directions.

This property causes the polarization of the field to vary randomly hence eliminating the

need, or the utility of physical rotation of test objects in the field. This has its obvious

advantages and disadvantages as is apparent from the results and conclusions given in this

report.

Two analytical approaches can be used to provide basic knowledge for designing a reverberation chamber. One involves the direct solution of Maxwell's equations with time

varying boundary conditions. A formal solution using this direct approach is rather difficult

to obtain. In the second approach, suitable linear combinations of basic eigenmodes of the

unperturbed cavity (without mode stirrer or tuner) with time-dependent expansion coefficients

are taken to represent the field and to satisfy approximately the boundary condition on the

surface of the rotating mode stirrer or tuner [8]. The main advantage of this latter approach

is that the unperturbed eigenfrequencies and eigenmodes are much easier to calculate, and the

problem can be reduced to a more familiar one under special conditions. A necessary condition

for the validity of this method is, however, that the total number of eigenmodes which can exist inside a chamber be large for a specified frequency and chamber size. Thus, the

measurement technique using reverberating chambers is good for high frequency application.

Typical frequencies of operation are from a few hundred MHz to 18 GHz and above.

The frequencies at which particular modes can exist inside a shielded, rectangular

enclosure of dimensions a, b, and d are given as [9]

f = 150 / (-) + (^) + (^) (MHz) (1)

mnp a b d

where m, n, and p are integers.

Figure 2.1 gives the distinct frequencies of resonances of the first few modes for the

NBS reverberation chamber. There are 25 resonant modes at distinct frequencies below 150 MHz

and 63 resonant modes at distinct frequencies below 200 MHz.

As expected, the total possible number of eigenmodes, N(f), inside an unperturbed,

lossless, rectangular chamber increases in steps with frequency. A smooth approximation to

N(f) has been given by [8,10,11]:

N (f) = -^ abd {J}' - (a + b + d) - + ^ , (2) s 3c' c 2

where abd in m^ represents the chamber volume, f is the operating frequency in Hz, and c is

the speed of wave propagation in the chamber medium (usually air) in m/s. Note that the first

term in (2) is identical to the well-known Weyl's formula derived originally for the same

problem by a different approach, and is proportional to the chamber volume and the third power

of frequency. The second term is the edge term, which is proportional to the sum of the

linear dimensions of the chamber. This term may by used to modify Weyl's result, especially

in the lower frequency range. Also, the inner surface area of the chamber, 2(ab + bd + da),

is not involved in (2). An example is given in figure 2.2 showing N(f) as curve 1, N (f) as curve 2, and Weyl's formula as curve 3 for the NBS chamber. Note that none of the dimensions

of the NBS chamber (2.7*1 m x 3-05 m x 4.57 m) are equal. Equivalent examples for a squarebased chamber (2.17 m x 1.19 m x 4.19 m) and a cubic chamber (3-37 m)^, both of which have the same volume as that of the NBS chamber, are shown respectively in figures 2.3 and 2.4 for

comparison purposes. Clearly, wider steps for curve 1 in figures 2.3 and 2.4 as compared with

figure 2.2 are observed. This is true even though the smooth approximation N (f) remains

almost identical for all the three chambers. The main reason for this is due to the increased

mode degeneracy for the last two chambers, under which the total number of distinct eigenmodes

with respect to a given operating frequency and chamber size decreases.
While the total number of eigenmodes inside an unperturbed chamber is an important design

criterion, another equally important factor to consider is the mode density function, dN/df,

which represents the change in number of modes in a given frequency interval. Ideally, the

chamber should be designed, if possible, so that the distribution of the modes is uniform. To determine the exact shape of dN/df involves using impulse functions since they are the

derivatives of step functions. It is not difficult to see that within a given frequency

interval, the average distance between the different impulses for the NBS chamber is shorter

than that for the other two chambers having the same volume. An alternative quantity to examine for exhibiting this property is

AN = /^^ § df . (3)

which represents the increase or decrease in mode number within a frequency interval of Af.

Results of AN when Af = 1 MHz are presented respectively in figures 2.5 through 2.7 for

the NBS chamber, the square-based chamber, and the cubic chamber. The uniformity of mode

distribution in the frequency interval of 1 MHz is better for the NBS chamber (figure 2.7).

This is the reason that the NBS chamber was designed with unequal dimensions. As a consequence, more uniformity for the electromagnetic field is expected within the NBS chamber

than for chambers that have two equal sides or that are cubic, with the same volume and

frequency of operation. Or, the NBS chamber should be capable of being operated with an extended lower frequency limit than other chambers of the same volume, in order to meet a given degree of uniformity for the final, expected field distribution. Thus, one of the

general design criteria for a reverberating chamber is to make the volume as large as possible

and the ratio of squares of linear dimensions as nonrational as possible.

A third design criterion, namely, the quality or Q factor, must also be considered in

designing a reverberation chamber. Since there are so many eigenmodes which may exist in an unperturbed chamber with each mode carrying its own Q value [8,10,11], it is not always

trivial to define a quality factor for the chamber as a whole. A composite quality factor for an unloaded chamber (without an EUT in it) within a specified frequency range can be obtained

approximately from the equation [8], i

n _ 3 V 1

1 D a b d

(i*)

where V is the chamber's volume in cubic meters, S is the internal surface area in square

/ 2 meters, and 6 = / is the skin depth in meters, A is the wavelength in meters, and a, b,

s wpo

and d, are the chamber's internal dimensions in meters.

The physical meaning of {^) may be interpreted by comparing it with the individual Q

values of all the modes in the form of a cumulative distribution. Since V/(S6 ) is a common

s factor whether the composite quality factor defined above or the quality factor for individual

modes is considered, it is more convenient to present the results in terms of 1 /Q values

normalized with respect to S 6 /V. Thus, the variable used herein is

a = i (V/S 6 ) . (5)

Q s

Examples of the cumulative distribution of a for the NBS chamber are given respectively

in figures 2.8 - 2.10 for three different frequency bands. For the frequency band of 1 80 to 200 MHz in figure 2.8, the total number of modes existing in this band of 20 MHz is 69, with

each mode having its own Q-value. The probability of having a high upper-bound value of a ^ 0.80 (or a lower-bound for Q) is almost 100?, and that for a low value of a ^ 0.48 (or a high

value for Q) is only about ^0%. This implies that almost all of the 69 modes in this

frequency band have a ^ 0.80. The arithmetic mean of 0.623 and the standard deviation of

0.090 are also indicated in the figure. The probability of having a i 0.623 (arithmetic mean)

is 50?, meaning that at least one half of the 69 modes have a ^ 0.623.
For the case presented in figure 2.9, where the frequency band is from 330 to 350 MHz,

also of a bandwidth of 20 MHz, there are 261 modes, an increase in number of modes relative to that in figure 2.8. This is because of higher frequency. A similar interpretation of the a values (or Q values) carried by these modes in terms of probability applies. There are now a small number of modes (low probability) carrying a value of a as low as O.^JS (high Q). The

arithmetic mean and standard deviation are, respectively 0.630 (higher than the corresponding

value in figure 2.8) and 0.085 (lower than the corresponding value of figure 2.8). A higher

value of arithmetic mean implies that one half or more of the 261 modes carry a higher value

of a (lower Q) compared to the frequency band considered in figure 2.8. A decrease in

standard deviation reveals that a greater number of modes have a-values closer to the

arithmetic mean.

If we consider a still higher frequency band ^80 to 500 MHz such as that illustrated in

figure 2.10, 53^ possible modes will exist in the same bandwidth of 20 MHz. The arithmetic

mean increases further to 0.646 while the standard deviation decreases further to 0.074,

indicating that a greater number of modes will have still higher a values near the arithmetic

mean. This tendency, increasing in arithmetic mean and decreasing in standard deviation with

increased frequency, yields a limiting mean of a ^ 0.667 with a 50? probability, which also

agrees precisely with the limiting value for composite a derived from (M) and (5).

Thus, even though there are a large number of possible modes existing in a specified

operating frequency band for a reverberating chamber, with each mode carrying its own value of

a or Q, the probability that a i 0.667 (or Q ^ 1.5 V/So ) is 50?. This implies that one half

of the modes have a-values less than 0.667. Preliminary estimation of a quality factor to characterize the reverberating chamber as a whole, based on the simple expression of Q in (4),

for the purpose of predicting the field strength level to be generated in the test zone is

indeed very useful.

Finite Q values also imply that more than 1 mode can be excited at a single frequency.

The extent to which modes not specifically resonant at a given frequency are excited is, of

course, dependant upon the particular modes' Q, and how close the modes' resonant frequencies

are to the given frequency.

The composite Q estimated from (4) is considered an upper-bound value because it does not take into account losses other than that due to wall conductivity. In reality, some loss will

also occur due to leakage from the chamber, loss in antenna support structures, etc., and loss

in the chamber's wall coatings. Hence an alternative means of determining chamber Q can be

achieved from measuring the chamber's loss. Chamber loss is determined experimentally by

measuring the difference between the net input power, P , delivered to the chamber's

transmitting antenna, and the power available, P , at the reference antenna terminals. A photograph showing the interior of the NBS reverberation chamber is shown in figure 2.11. If

the energy is uniformly distributed over the volume of the chamber, an empirical value (Q') can be obtained [6] using the equation,

V ^r

Q' = 16 TT^ It / , (6)

t

where V and A are as previously defined.

Typical losses for the NBS chamber are shown in figure 2.12. The two curves show the

average and minimum loss as a function of frequency. These results were determined

statistically by rotating the chamber's tuner through 200 increments of 1.8 degrees and

measuring the chamber's loss at each position for all test frequencies. The smooth curves

are an estimated curve fit for the data.

Results obtained using (4) to calculate the composite Q and by using the data shown in

figure 2.12 and (6) to calculate the experimental Q' are shown in figure 2.13- Figure 2.13a

gives the curves for the calculated values of Q and Q' and figure 2.13b shows the ratio of Q to Q'. At frequencies above approximately 1 GHz the ratio approaches a constant value

approximately equal to 3 or a loss equivalent of approximately 5 dB.
The Q factor of the chamber, of course, influences the rf input power requirements to generate the EM field levels inside the chamber for performing susceptibility tests. The

average power received by the reference antenna, P in watts, is related to the average power

density, P in watts per square meter, of the EM field inside the chamber by the equation,

P. = P /A (W/m)^ , (7) a r r

where A is the average effective aperture in square meters of the receiving antenna.

If the receiving antenna is subjected to EM energy coming from all aspect angles and

random polarizations, the average gain of the antenna over M ir solid angle is unity. (i.e..

The field distribution at each point in the antenna aperture plane is assumed to be a composite of randomly polarized plane waves. This implies that the orientation of the

receiving antenna will not influence the measured response and hence the effective gain of the

antenna is unity.) The effective aperture of the antenna then is given as , A = A^/8ti [12].

However, data obtained, as shown later in this report, indicates that these conditions are not achieved ideally (the field is not completely randomly polarized and incident at all aspect

angles and the assumption that the average gain for the antenna is one is not exact). Hence,

a more practical value to use for the effective aperture appears to be X^/4ir. This value has

been suggested previously for use in reverberation chambers for determining the "equivalent"

average power density, P [4]. Equation (7) then becomes,

Hn P P. = —TT^ (W/mM . (8)

d X Combining (6) and (8), we can obtain an expression for comparing the average, equivalent power

density inside chambers of different size, assuming equal net input power, or

P

di ^ V, q; ^ S^ 6^

^ ^gj

d; Vi Ql S, 6i

where the subscripts 1 and 2 refer to the two different enclosures, #1 and #2. For example, assume the #1 enclosure is the NBS enclosure with Si = 69.63 m^ and the #2 enclosure is a larger chamber constructed of the same metal (6i = 62) with dimensions, 3.51 m x 5.18 m x

10.82 m, or S2 = 224.42 m^ ; this would give a ratio in average power densities (assuming the

same net input power) of P' /P' = 3.22 (i.e., the average power density inside the larger

d 1 d 2 enclosure would be approximately 1/3.22 or O.31I times as much as that in the NBS enclosure).

Note that the validity of (9) is dependent upon a number of assumptions alluded to in its

derivation.

2.2 Physical Design Considerations

A number of criteria should be considered in physically designing a reverberation chamber

EM susceptibility/vulnerability measurement system. They can be addressed under the following

categories:

1. Chamber physical shape and volume,

2. Chamber quality factor (Q),

3. Chamber auxiliary needs (venting, electrical power, EUT visual monitoring, EUT operational and functional monitoring requirements),

4. Tuner/stirrer (s) design, and

5. Chamber excitation and field monitoring.
2.2.1 Chamber Physical Shape and Volume

This criterion was addressed in Section 2.1. For optimum chamber performance (i.e.,

spatial field uniformity and accuracy in determining the test field level), especially at the

low end of the frequency intended for use, the volume of the chamber should be as large as possible and the ratio of the squares of the chamber's linear dimensions should be as nonrational as possible. Choice of chamber size would be dictated by test volume size

requirements, lowest test frequency, and budget considerations.

2.2.2 Chamber Quality Factor, (Q)

The second criterion, that of chamber Q, is established by carefully considering tradeoff options. If one has the option of designing and constructing a new shielded chamber, it

is advantageous to use solid welded aluminum or copper construction since this will result in

a higher Q than if sheet steel is used. Presumably one can always lower the Q of the chamber,

if desired, by inserting material such as lossy wall coatings or a limited amount of rf

anechoic material. The reason for lowering the chamber Q is to increase the bandwidth of the

chamber's modes, thus improving mode overlap and smoothing the EM field uniformity vs. frequency response characteristics, especially at the lower test frequencies. Doing this,

however, increases the rf input power needed to generate the required field strengths and

reduces the effectiveness of the chamber's tuner to redistribute energy uniformly into modes

in all three axes of the chamber. In addition, the time required for the chamber test field

to arrive at its steady state condition, after the input power to the chamber is applied, is a function of chamber Q. The higher the Q the longer the settling or charging time. This could

have significant implications if the reverberation chamber is to be used for pulsed rf

susceptibility testing. Regardless of the metal used in the chamber's construction (aluminum,

copper or steel) it should be standard practice to keep the chamber clear of lossy material

such as wood or absorbing materials except for special purposes.

2.2.3 Chamber Auxiliary Needs

The third criterion, chamber auxiliary needs, must be established based upon the intended use and the upper test frequency for use. Venting panels should use screens with apertures

significantly smaller than waveguide below cutoff at the maximum intended test frequency.

Electrical power supplied to outlets inside the chamber, EUT visual monitoring, and EUT operational and functional monitoring requirements are similar to conventional shielded

enclosure requirements. A bulkhead panel similar to that shown for the NBS reverberation

chamber in figure 2.1^1 can be used to access the excitation and reference receiving antennas,

and the EUT. Care must be taken to ensure that the shielding integrity of the enclosure is not compromised by access holes or cables, etc. This may require the use of high resistance

(carbon Impregnated) lines [13] or fiber optic links for monitoring the EUT. In addition,

waveguides below cutoff access ports can be very useful.

2.2.4 Tuner Design

The fourth criterion is to design the tuner to ensure its effectiveness to redistribute

the energy inside the enclosure and hence to tune the field. To achieve this, the tuner must

be electrically large (>X/2 at the lowest frequency of operation) and be shaped or oriented to distribute energy into all possible modes. Three such tuners are shown in figures 2.15a,

2.15b, and 2.15c. The first tuner (figure 2.15a) was developed by McDonnell Douglas Corp.

[2,14,15] after extensive testing to optimize the design for use in their translat ional

electromagnetic environment chamber (TEMEC) facility. The second tuner (figure 2.15b) is used

by the Naval Surface Weapons Center in their reverberation chamber [16], The third tuner

(figure 2.15c) is used in the NBS reverberation chamber. The tuner is mounted as shown in

figure 2.16, with the blades bent at an angle of approximately 45 degrees to the ceiling to improve its scattering of the field evenly in all directions. The tuner mounting includes a shielded housing with internal metal wipers to prevent rf leakage from the chamber via the

tuner shaft to the stepping motor. Details of the housing and motor mounting arrangement are shown in figure 2.17. The tuner controller system which includes the stepping motor and a computer accessed controller, allows movement of the tuner in increments as small as 0.113

degrees (3200 steps per revolution) at rates from seconds up to hours per revolution. The

motion was optimized for as smooth a motion of the tuner as possible.

A test to determine how effectively the tuner is functioning is to measure the ratio of

the maximum to minimum received power of the receiving antenna as a function of tuner

position. This is done while maintaining a constant net input power to the enclosure's
transmitting antenna. The results of such measurements made with the NBS tuner are shown in

figures 2.1 8a and 2.1 8b. The magnitude of the ratio is dependent upon a number of factors

including tuner shape, size, orientation, and the Q of the enclosure. The average value of

the maximum to minimum ratio is higher in th6 empty chamber. (Data for figure 2.1 8b were obtained with 4 pieces of 66 cm x 61 cm x 61 cm rf absorber placed in the center of the

chamber 0.5 meter above the floor). The purpose for inserting the absorber was to simulate a gross loading effect of an EUT placed in the enclosure. A lower loss (ratio) is indicative of

a higher Q and more effective mode tuning. This influences the spatial uniformity of the test field (statistically) as is shown in section 2.3. A reasonable guideline for proper

operation of the tuner is a minimum tuning ratio of 20 dB.

Multiple tuners have been used in some reverberation chambers [3,6]. Typically they are mounted on opposite walls to improve the stirring of the fields in the chamber. This is

especially important if the tuners are flat, thus acting as scatterers in only one plane. The

tuner controller system used in the NBS system allows for control of several tuners

simultaneously. This may be particularly advantageous if the reverberation chamber is

especially large or is compartmentalized (multiple sections). Examples of compartmentalized

chambers are a large chamber divided into two sections by a separating wall or a small chamber

placed inside a large chamber. Both arrangements have been proposed for using the

reverberation chamber method for measuring shielding effectiveness of materials and enclosures

[17].

2.2.5 Chamber Excitation and Field Monitoring

The fifth consideration in designing a reverberation chamber EMC measurement system is in

the selection and mounting of appropriate antennas for exciting and monitoring the EM fields

inside the chamber. The following parameters are used in selecting the antennas:

a) frequency range of interest,

b) input power rating (>200 watts),

c) bandwidth (>10:1 if possible),

d) minimum VSWR (low as possible),

e) efficiency for exciting modes inside chamber,

f) minimum size, and

g) durability.

The typical frequency range of application is from 200 MHz to 18 GHz or higher. A number

of candidate antennas could be used in this range. No single antenna has sufficient bandwidth

to cover the full range with the possible exception of the long wire antenna. Based upon the

above and, to a certain extent, the antennas available at the Electromagnetic Fields Division

of NBS, the following were selected for evaluation.

a) Long wire antenna (200 MHz - 18 GHz),

b) Log periodic antenna (200 MHz - 2 GHz),

c) Monopole antenna (200 MHz - 1 GHz),

d) Bow-tie antenna (200 MHz - 1 GHz),

e) Leaky 50 ohm coaxial cable (200 MHz - 1 GHz),

f) Ridged horn (1.0 GHz - 12 GHz),

g) Double ridged circular horn (2.0 GHz - 18 GHz).

The efficiency with which energy can be injected into or coupled out of the chamber via

transmitting or receiving antennas is determined by: 1) the voltage standing wave ratio (VSWR)

of the antennas (i.e., the impedance match between the rf source and the transmitting antenna

or between the receiving antenna and its output detector), and 2) the ability of the antennas

to couple energy into or out of the particular modes that exist at the test frequencies of

interest. Rotating the tuner changes the chamber's boundary conditions and hence, shifts the

mode excitation frequencies. This, of course, changes the characteristics of the field inside

the enclosure which in turn influences the effective VSWR of the antennas. The Q factor of

the enclosure as a resonant cavity also has considerable effect upon the VSWR of the antenna. This is particularly true at frequencies below a few GHz.

The placement and orientation of the transmitting and receiving antennas can also

influence the operation of the chamber [18]. Two positions or orientations are recommended:

1) position the transmitting and receiving antennas in different corners of the chamber,

oriented toward the corners as shown in figure 2.19, or 2) position one of the antennas in a corner oriented toward the corner, for example the reference receiving antenna, with the other

antenna (transmitting antenna) sufficiently far away and oriented toward the tuner. The first
arrangement was selected for use in the NBS chamber. The purpose for these configurations is

to couple energy into and out of all chamber modes as efficiently and uniformly as possible

without significantly favoring particular modes or favoring a direct path coupled signal

between the transmitting and receiving antennas.

Installation of a long wire antenna inside the chamber is different from other antennas

because it uses the chamber wall as its ground plane to obtain as close to a 50 ohm impedance

as possible. Details for designing the taper transition region of the long wire antenna are shown in figure 2.20. A photograph of the long wire antenna installed inside the NBS chamber

is shown in figure 2.21. The long wire extends around two surfaces of the chamber. This is

done to achieve, however somewhat limited, the purpose of the locations and orientation

configurations referred to above for other conventional antennas.

G Based upon the results of data obtained for various antenna pairs selected from the above

list, the following four antennas were chosen for use in the NBS chamber in the following

frequency ranges:

1) Long wire (200 MHz - 1000 MHz), receiving mode,

2) Log Periodic (200 MHz - 1000 MHz), transmitting mode,

3) Ridged horn (1.0 GHz - 10 GHz), transmitting and receiving modes,

M) Double ridged circular horn (2.0 GHz - 18 GHz), transmitting and receiving modes.

Within the recommended frequency bands of operation, the long wire and log periodic

antennas can accommodate up to 1000 watts input power, and the ridged horns and double ridged

circular horns can accommodate up to 200 watts input power.

A number of preliminary tests were performed to determine the operational parameters of

the NBS reverberation chamber using these antennas and to evaluate the interactions between

EUT, the chamber, and the rf sources used in performing these measurements. Some of these

tests and their results were previously published [19]. The VSWRs and coupling efficiency of

these four antennas placed inside the empty NBS chamber are given in figures 2.22 and 2.23.

Figure 2.22 shows the maximum, average, and minimum VSWR obtained statistically by measuring

return loss from the antennas, operating in the transmitting mode, as a function of tuner

position at discrete frequencies from 200 MHz to 18 GHz. The tuner was stepped at 1.8 degree

increments (200 steps) through a complete revolution. Figure 2.22a is for the long wire

antenna operating over the complete frequency range. Figure 2.22b, is the composite VSWR of

three antennas (#2, #3, and #h) used within the frequency bands shown in the figure's caption.

In the past a long wire antenna has been used quite extensively as a reference receiving

antenna across the full frequency range [^,1^1,17,]. Its input VSWR is not as low, especially

at frequencies above 1 GHz, as for the composite of the three antennas. Also, at frequencies

above approximately 2 GHz, rotation of the tuner appears to have a minor influence on the VSWR

of the antennas. This feature can have considerable impact upon the decision as to what

approach to use in performing susceptibility measurements as discussed in section M.I of this

report. Figure 2.23 shows the coupling efficiency or loss between the long wire antenna

transmitting (200 MHz - 18 GHz), and a composite of the three antennas receiving. This figure

is provided for comparison with figure 2.12. The long wire antenna is not as efficient in

coupling energy into the chamber and hence, the loss is greater, particularly above 1 GHz.

The quality factor of the chamber as a resonant cavity also has considerable effect upon

the VSWR and coupling efficiency of the antenna placed inside, especially at frequencies below

a few GHz. This is shown in figures 2.22c and 2.24. These data were obtained with four

pieces of 66 cm x 61 cm x 61 cm rf absorber placed in the center of the chamber's test zone. Note the significant reduction in the VSWR variations of the transmitting antenna associated

with the substantially lower Q in the enclosure and the significant increase in the chamber

loss.

2.3 Determination of Wave Impedance and E-Field Amplitude Distribution Inside

Reverberation Chamber

2.3.1 Determining the Test Field and Wave Impedance Amplitudes

The field strength in the chamber can be determined in two ways. The first is to measure

the power received by the reference antennas, and then determine the equivalent power density

in the enclosure from (8). The equivalent electric field, E , is then found using the

expression,
^a " / n' Pjj = ^ / 30 P; (V/m), (10)

where n' is the statistically averaged wave impedance in the chamber. This averaged wave impedance is assumed to be approximately equal to 1 20it ohms. Obviously, the wave impedance

inside the reverberation chamber will have large variations as a function of tuner orientation

and chamber location. To test the validity of (10), independent measurements were made of the

maximum, average, and minimum magnetic and electric fields in the chamber. These measurements

were made using a one centimeter diameter loop probe and a one-centimeter long dipole probe.

The probes were rotated through three orthogonal orientations aligned with the chamber axes

and located at the center of the test zone. The magnitudes of the total magnetic and electric

fields were then determined as the square root of the sum of the squared values of each of the

three components respectively for both the magnetic and electric fields. The corresponding

ratios of the electric-field and magnetic-field amplitudes for a data base of 200 positions of

the tuner were then used to determine an "equivalent" wave impedance. The results are shown

in figure 2,25. Four curves are given. Three curves show the maximum, average and minimum

wave impedance determined as a function of frequency. The fourth curve shows the wave impedance calculated from the ratio of E to H when the electric-field was a maximum. Even though the wave impedance varies widely as expected with frequency, the average wave impedance

at frequencies above 200 MHz (the lower frequency limit recommended for this chamber) is

approximately 120it ohms. This then, provides evidence that (10) is valid, at least for

determining the average E-field in the chamber. The fourth curve was included because, as will be discussed later in this report, the convenient parameter for comparing reverberation

chamber with anechoic chamber obtained EUT susceptibility data is the EUT's peak response.

This typically corresponds to a maximum electric field in the reverberation chamber. Note

that the wave impedance corresponding with the maximum E-field typically is greater than 120-1: ohms and was found to be as large as 1600 ohms thus contributing to an error as large as 6 dB

in determining the maximum E-field if (10) is used.

The second method used to determine the field strength in the reverberation chamber is to measure the electric field using an electrically small dipole probe that has been previously

calibrated in a standard uniform field. This is the same dipole probe, referred to above,

that was used to determine the chamber's wave impedance. The assumption made in using the

probe is that since it is electrically small, the fields measured in the reverberation chamber over the aperture of the dipole will be uniform (i.e., "equivalent" to the standard uniform

field used in the probe's calibration); and hence the probe's response will give an accurate

measurement of the "equivalent" field strength in the chamber. Results of the measurements

comparing the electric-field strength generated in the chamber based upon these two methods

are shown in figure 2.26. The maximum and average E-field strength data were normalized to one watt net input power. The agreement shown is typical of the random variations in the data

used to determine the field in a reverberation chamber. The systematic offset difference

between the field determined using the reference antenna and that determined using the probe

is, however, less than 3 dB. This result also strengthens the validity of (10).

2.3.2 Maximum Versus Average Amplitude Responses

Another important observation from figure 2.26 is the approximate 7-8 dB difference in

signal amplitude between the maximum and average field strengths. This can be explained

simply in terms of the structure of the cavity modes in the chamber [20]. For a cavity of

dimensions, a, b, and d, modes in all three dimensions can be represented as

/ \

. mirx . rnry . pirz / ^ , \

d) (x,y,z) a sm sin —rr- sin ^--r— , (11) ^mnp •' a b d

where x, y, and z correspond to the three orthogonal axes of the chamber and m, n, and p are

the associated mode numbers.

An antenna typically responds to a specific field component, or in the reverberation

chamber case, to the composite field impinging upon its aperture. However, measured power is

related to A^ x,y,z). The maximum value of A^ (x,z,z) occurs when each component is a ^mnp •'

^mnp ^ maximum or Max ((|)^ (x,y,z) ) i 1. (12)

mnp

The average value of i,^ (x,y,z) is given by

mnp
The ratio of Max (4^ (x.y.z) )/Ave (A^ (x,y,z)) in the limit then is 8 which corresponds

mnp mnp

to 9 dB (i.e., this is the theoretical maximum difference that can exist between the maximum

and average responses of an antenna or EUT measured in a reverberation chamber). In practice,

the mode mixing is not 100 percent efficient to achieve a perfect average nor does one obtain

a perfect maximum in all three dimensions. Hence the average difference of 7 to 8 dB shown in

figure 2.26 is expected.

In the past, a question regarding the validity of maximum or "peak" reverberation chamber

results has been raised. However, this question seems to be resolved as apparent by examining

the relationship between maximum and average measurements in the reverberation chamber

exhibited in figure 2.26 and from the implications of (12) and (13). These results suggest one can extract one set of data (e.g., average) from the other (e.g., maximum) quite

accurately (within ± 2 dB) , assuming of course, that the response of the EUT is linear.

2.i4 Spatial E-Field Distribution

Tests were made to determine the uniformity of the maximum and average values of the E- field in the chamber as a function of spatial position and frequency. Seven NBS isotropic

probes [21 ] designed to operate at frequencies up to 2 GHz were placed inside the enclosure as shown in figures 2.19 and 2.21. Each probe has three orthogonally oriented dipoles aligned

with the enclosure axes. Measurements were made of the field strength of each orthogonal

component at the seven locations for each tuner position (200 steps of 1.8 degree increments).

The maximum and average values for each component and the corresponding amplitudes were then

determined from the complete data set for a normalized net input power to the chamber of 1 watt. The results of these measurements are shown in figure 2.27. These measurements were

made in 50 MHz increments from 100 MHz to 2.0 GHz. The spread of the data points show the

spatial field variation inside the enclosure at the indicated frequencies. Note at 200-300 MHz the spread and potential errors in determining E-field amplitude i s as great as ±8 dB,

decreasing to approximately +2 dB at 2.0 GHz. Note also the large difference in the three

orthogonal components at frequencies below 150 MHz. This is especially apparent from

inspecting figure 2.28 which shows the average values of the seven statistically determined

average and maximum E-fields for each component and their composite total determined from

figure 2.27. Strong mode structure is indicated in the chamber at frequencies below 150 MHz

(i.e., the presence of a dominant mode with its associated directional properties). Hence,

there are insufficient modes for proper operation at these frequencies. At frequencies above

150 MHz, the relative amplitudes of the field components are approximately the same and the

composite total of the average E-field components is approximately M.8 dB greater than the

individual components. This indicates that the measured value of the average of each

component is independent of polarization of the dipole. (i.e., E , i is independent of

E , , , etc.) . Thus, y(ave)

E, , . = /~iE~, J^ + 'i^. ,)= + (E . T^ = /T(E. . ). t(ave) x(ave) y(ave) z(ave) (x,y,or z)ave

The composite total however, of the E-field components' maxima (figure 2.28b) is less

than 4.8 dB. This indicates that the maximum measured values for each component are not independent, (i.e., E ,^ ^ , , is a function of E ,^ ^ ,v, etc.). The implication is that if

x(total) y(total) ^ multiple receptors are involved in establishing the maximum susceptibility of an EUT (or for

example in measuring the E-field in the chamber by using an isotropic probe with 3 orthogonal

dipoles), the difference between the maximum and average response may be less than the typical

7 to 8 dB referred to in section 2.3.

2.5 Multiple Excitation of the Chamber

Electromagnetic fields were generated inside the chamber using two separate antennas

simultaneously excited in the frequency ranges, (200-400) MHz, and (1000-2000) MHz. The

antennas used for the frequency range (200-400) MHz were a log periodic and a long wire

described previously. Two ridged horns were used in the frequency range (1.0-2.0) GHz. The

spatial, statistical, E-field uniformity did not improve significantly over using a single

antenna excitation in the 200-400 MHz frequency range; however, it did improve slightly (from

approximately ± 2 dB to + 1.5 dB variations) in the frequency range (1,0-2.0) GHz. 10
The E-field amplitude in the chamber decreased when using two excitation antennas, in

both frequency ranges, assuming the same net input power as for a single antenna. The

decrease was approximately 1 dB in the frequency range (200-400) MHz and approximately 1.5 dB

in the frequency range (1.0-2.0) GHz. This loss however, can be accounted for in the losses

in the additional rf transmission line cables and the second excitation antenna (i.e., the

antennas are not 1005^ efficient in converting input rf power to radiated power).

3. Interaction Effects Between Chamber, Source and Reference Antennas, and EUT.

3.1 Placement Constraints of EUT

Constraints on the placement of EUT inside the reverberation chamber are a result of the

proximity effect of the chamber walls on the test field and upon the EUT. Measurements were made of the E-field close to the chamber's walls for comparison with measurements made of the

E-field within the test zone outlined by the matrix of seven probes shown in figure 2.21 Two

locations were selected: 1) 0.5 m from the chamber's side and back wall, 1.0 m above the

floor; and 2) 0.12 m from the side wall approximately mid-way between the chamber's ends and

0.5 m above the floor. Location 1 was selected so the EUT test zone would be clear of

obstructions but also with the probe far enough from the chamber's walls, hopefully, to avoid

significant proximity effects. Location 1 measurements were consistent with the measurements

made at the 7 probe locations. Location 2 was selected to determine just how significant the

proximity effect is at distances less than one third wavelength (<800 MHz). The average E- field measured at location 2 was approximately 2 dB lower at frequencies from 200 to 400 MHz

than the E-field measured in the test zone. The field close to the chamber wall then

increased as a function of frequency, approaching the test zone measured field strength at

frequencies above 1 GHz. These results indicate a need to maintain a minimum spacing for the

reference antenna, field measurement probe(s), and/or EUT of at least A/3 from the chamber's

walls at the lowest test frequency. This equates to approximately 1/2 meter at 200 MHz for

the NBS chamber. An exception to this guideline may be a desired spacing between the EUT and

the chamber floor or walls. This spacing may be dictated by the test plan. If the EUT is electrically large (many wavelengths) it may be necessary to have a separation distance from

the chamber walls greater than A/3 at frequencies where A/3 is less than 1/2 meter or greater

than 1/2 meter under some test conditions to prevent shadowing effects from influencing the

spatial distribution of the test field. Results of scattering effects measurements discussed

in section 3-2 suggest shadowing is not a slgnficant problem, if the EUT is placed in the

center of the test zone as far from the walls as possible.

3.2 Scattering Effects of Metal Objects upon E-field Distribution

Two test objects were selected to simulate an EUT placed in the chamber to evaluate their

scattering effect upon the field distribution inside the chamber. The first object was a solid welded aluminum box 30 cm x 50 cm x 60 cm in size. The second was an electronic

equipment rack 56 cm x 67 cm x 114 cm in size. Tests were made to determine the E-field

uniformity or distribution over the test zone matrix defined earlier using 6 isotropic probes

(figure 2.19) with each of the two test objects placed at the center of the test zone. (The

probe at the center of the test zone was removed to accommodate the test objects.) Figures

3.1a and 3.1b show the two test objects placed inside the enclosure. The mean value of the

maximum and average values for each E-field component (vertical, longitudinal, and transverse)

and their composite total were determined for each of the 6 probes. The results, shown in

figure 3.2, give a comparison with the empty chamber E-field distribution measurements shown

in figure 2.28. Little or no difference was noted in the statistical (average and maximum)

values measured.

3.3 Loading Effects of EUT on Chamber

One of the concerns expressed about using a reverberation chamber for EMC measurements

was the realization that if the EUT absorbed energy from the chamber (i.e., demonstrates

susceptibility) it would reduce the Q of the chamber and thus affect the measurement results.

Typically this is compensated for by simply increasing the net input power to the chamber

transmitting antennas as required. This may not be sufficient if inserting the EUT lowers the

chamber's Q to the extent that the chamber no longer reverberates or the tuner will no longer

sufficiently stir the modes, (i.e., the chamber no longer functions properly). Recall that

the absolute amplitude of the test field level inside the chamber is determined from the

reference antenna received power measurements. The assumption is that this measurement is

unaffected by the loading effect of the EUT. Two simple tests were used to evaluate the

loading effect: the first was to insert a 500 MHz, half-wave, resonant dipole near the center

of the chamber's test zone to determine if energy coupled from the chamber to the dipole would

11
reduce the field strength in the chamber. This test was intended to simulate the loading

effect of a simple resonant EUT. Field strength measurements were made again using the seven

probe matrix and the long wire antenna as a reference receiving antenna to determine the level

of the test field, before and after inserting the resonant dipole. A constant normalized

input power of 1 watt was applied at the input of the chamber log periodic transmitting

antenna to establish the field in the chamber. The following observations were made:

1) Energy is conserved (i.e., power coupled from the chamber via the dipole results in a proportional decrease in the E-field in the room).

2) The 500 MHz resonant dipole and the long wire receiving antenna coupled approximately

the same amount of power from the room.

The seven probe matrix used to determine the spatial distribution of the E-field inside

the chamber, also load or reduces the Q factor in a similar fashion to the resonant dipole.

Each of these probes couple a small amount of energy out of the test field. In addition, they

have lossy transmission lines made up of carbon loaded teflon that serve to convey their

detected dc signals to their instrumentation located outside the chamber. These lossy

transmission lines increase the chamber's loss up to 5 dB at 2.0 GHz. However, this amount of

loss did not seem to significantly influence the ability to determine the field level in the

chamber, with or without the presence of the probes by using the reference receiving antenna.

The field level simply was lower for the same net input power due to the loading effect of the

probes in the chamber.

The second test used to evaluate the loading effect was to place varying amounts of rf absorbing material inside the chamber. This was done to get an indication of just how much

loading the chamber could tolerate before it fails to operate properly and/or large errors existed in determining test field level and EUT response. Progressively greater amounts of

absorber were added until approximately 90 percent of the net input power was being absorbed

(i.e., the chamber loss was increased by approximately 10 dB) . The amount of rf absorber

required was four pieces of 66 cm pyramidal high performance absorber 61 cm x 61 cm square.

Results for tuner effectiveness, VSWR and chamber loss with absorber loading were shown in

figures 2.l8b, 2.22c, and 2.24. As indicated earlier, lowering the chamber Q reduces the test field level in the chamber for a given net input power. Inserting the 4 pieces of absorber in

the chamber lowers the field considerably as shown in figure 3. 3- This figure compares the

maximum E-field strength in the test volume defined by the 7 probe matrix inside the empty

chamber with the field strength after the chamber is loaded with the 4 pieces of absorber.

In summary, the following observations can be made from the data obtained (figures 2.1 8b,

2.22c, 2.24 and 3.3). Lowering the chamber Q:

1) decreases the effectiveness of the tuner (lower Max/ in ratio),

2) improves the VSWR of the transmitting and receiving antennas,

3) increases the chamber loss and hence increases the rf power required to obtain test

fields of the same level,

4) increases the uncertainty in determining the test field level and EUT response

(indicated by the larger variations in the E-field data obtained with absorber,

figure 3.3), and

5) decreases the spatial, statistical E-field uniformity.

In conclusion, the following guidelines are suggested. Inserting the EUT should not

lower the maximum or average received power from the chamber's reference antenna for the same

net input power into the chamber (before and after inserting the EUT) excessively. If these

ratios, net input power/received power (max or ave), increase more than 6 dB, or if the tuner's

average effectiveness decreases to less than 20 dB, use of the reverberation chamber is not

recommended.

4.0 1 >;rf orming Immunity Measurements

4.1 Planning the Measurements

A number of considerations are important in planning the measurements, writing the test

plan, and documenting the test results. One is the amount of data required to accurately

12
characterize the EUT. Equipment susceptibility to EMI is primarily determined by the degree

to which the interference field couples into and interacts with the equipment's components.

This undesired coupling is influenced by a number of equipment parameters such as: input/output, power line, and circuit lead impedances and lead lengths; impedances of circuit

components (especially those terminating lead wires); type of circuit components (particularly

active components); and amount and type of EMI shielding and filtering used. The

susceptibility of any particular equipment is usually a function of frequency, suggesting

resonance effects within the equipment with its input/output leads and other interconnected

equipment. These resonances may be caused, for example, by the reactance of the connecting

leads acting as an antenna, coupling with the input impedance of the terminating circuit

components. The quality factor (Q) of such a resonant circuit determines the maximum spacing

or increment between frequencies at which susceptibility tests must be performed. Automated

systems such as required by the reverberation chamber test methods are (by their digital

nature) discrete frequency systems. The number of test points one can obtain using such a system are limited by the memory or storage capacity of the computer, the measurement system

bandwidth, and the measurement time constraints. Thus, care must be exercised in choosing

frequency and amplitude measurement intervals compatible with the test system and the number

of test points required.

A second consideration is the test-field time duration versus reaction time of the EUT.

Some EUTs have components with relatively slow thermal time constants. This equipment must be

exposed to test fields with sufficient duration to allow reaction and interaction; otherwise

susceptibility tests may not be true indicators of the equipment's vulnerability. For example, thermocouple devices used to simulate electro-explosive devices may require one to

two seconds exposure time for maximum response. EUT soak time requirements influence the

approach (section 4.2) selected for performing the tests using the reverberation chamber

method.

Another important consideration relates to the need to simulate as closely as possible

"real world" operating conditions. Ideally, susceptibility tests should be performed with the EUT connected and operated in its operational environment. Since this, most likely, is not

possible, these operational conditions should be carefully simulated. This normally includes

making certain the EUT is tested with its wiring harness in the same configuration (as nearly

as possible) as when in actual use. (Actually, one of the advantages of the reverberation

chamber method is that the test results are independent of EUT wiring harness , input/output

and power lead orientation.) In addition, all connecting leads should be terminated with

equivalent impedances as when in actual use. Failure to simulate these conditions can result

in data that are misleading. An additional problem is the EUT-antenna-enclosure interaction

that exists inside any shielded enclosure. Antenna radiation or receiving characteristics are altered when enclosed inside a shielded environment. One should realize that the EUT always

interacts somewhat with the exposure field in any environment. What is difficult is sorting

out the normal open-field scattering effect from the unknown perturbation effects of the EUTantenna-enclosure interaction that is typically ignored in shielded room susceptibility

testing. Efforts to quantify this effect for reverberation chamber obtained results are discussed in section 5.

How to sense and telemeter the performance of the EUT from the test environment without

perturbing the EUT, the test environment or sensitive test equipment is another important

consideration. This is usually done by using either fiber optics lines or "invisible" wire

[13] (carbon impregnated Teflon) with appropriate readout devices.

Finally, one obvious purpose for performing susceptibility tests is to determine EUT compliance with pre-established performance criteria. For production item sampling, a worst

case EMI exposure environment with pass-fail criteria may be appropriate. However, for

engineering development of EMI-hardened equipment or for correcting EMI problems discovered in

existing equipment, diagnostic testing is needed. This type of testing requires knowledge of

the exposure field parameters, such as: frequency, repetition rates, and wave shape of test

signal; type and percent of modulation imposed; and polarization, amplitude and signal

waveform time variations. These parameters must be carefully selected, as part of the test

plan, controlled, and (for some tests) statistically characterized for the testing to be

meaningful. One obvious limitation of the reverberation chamber method for susceptibiltiy

testing is the loss of polarization information. However, this is in part compensated for

because worst case response characteristics of the EUT can be determined without repositioning

or orienting the EUT in the reverberation chamber since the test field is rotated around the

EUT. If carefully controlled tests are performed, resonances and susceptible EUT circuit

components can be determined, from which cause and effect relationships can be established.

These can then be modified or eliminated to improve the immunity of the EUT. Another

13
important consideration in performing diagnostic testing is the desirability of determining

how the EMI is coupled into the EUT. This requires separating, if possible, the sources of

interference reception, such as EUT input/output and power line leads, leakage through the EUT

case housing, or internally generated and coupled EMI. This can be achieved by a systematic

process of shielding and filtering various leads and functional sections of the EUT's circuit,

etc., while conducting the susceptibility tests.

4.2. Measurement Approach (Tuned vs. Stirred)

Two approaches are used for performing EMC measurements using the reverberation chamber.

The first approach, mode tuned, steps the tuner at selected, uniform increments, permitting

measurements of the net input power, reference antenna received power, field measuring probe

response and the EUT response at each tuner position. This allows corrections and

normalization of the received power, field measurements and EUT response to be made for

variations in the net input power to the chamber. These variations are due to changes in the

input VSWR of the transmitting antenna as a function of the tuner position. The number of

tuner steps per revolution that must be used is a function of frequency and chamber Q.

Typically, at least 200 steps or more are required to provide sufficient sampling to

accurately determine the statistical parameters of the test field and EUT response (maximum

and average amplitudes). If the sample size is too small, the fidelity of the measurements

suffers and true maxima, minima, etc. are not recorded. The mode tuned approach also allows

the operator to select long test field exposure times as needed to accommodate some EUT

response times.

The second approach, mode stirred, rotates (steps) the tuner continuously while sampling

the reference antenna received power, field probe response and EUT response at rates much

faster than the tuner revolution rate. These measurements are made using a spectrum analyzer,

diode detectors, and "smart" voltmeters with their own microprocessors capable of data storage

and calculation of statistical functions such as mean values and standard deviations. The

mode stirred approach allows large data samples (up to 9,999) for a single tuner revolution.

Tuner revolution rates are adjusted to meet EUT response time and output monitor response time

requirements. Typical revolution periods are from 1 to 12 minutes. This large sample, as compared to mode tuned, improves the accuracy in determining the statistics of the measured

parameters, however, at the expense of increased uncertainty due to failure to correct for net input power variations.

Hence a trade-off exists between mode tuned and mode stirred operation. An examination

of figure 2.22 suggests this trade-off occurs approximately between 1-2 GHz. (i.e.. The mode

tuned approach would be more accurate below 1-2 GHz where the mode density is not as great and

corrections can be made for variations in the net input power caused by large variations in

the input VSWR of the transmitting antennas. Mode stirring is more accurate at frequencies

above 1-2 GHz where VSWR variations in the transmit antenna as a function of tuner position

are small and large data samples of the test field and EUT response can be taken.)

4.3 Measurement System

4.3.1 Measurement Setup and Instrumentation Requirements

A block diagram of the basic NBS reverberation chamber EMC measurement system is shown

in figure 4.1. The test field is established by means of rf source(s) connected to

transmitting antenna(s) placed inside the chamber. Antennas used are discussed in section

2.2.5. Modes excited inside the chamber are then tuned or stirred by rotating the mode tuner which functions as a field-perturbing device. The EUT may be placed anywhere convenient

within the chamber provided no point on the EUT is closer than 1/2 meter to any wall, or ceiling. Placement relative to the floor is dependent upon a number of factors including

intended use configuration relative to ground-planes etc., and should be specified by the test

plan. Test, power, and control cables are routed to appropriate monitors, etc., outside the

chamber via shielded or filtered cables and feed-through connectors, high resistance lines,

and fiber optic lines as required to prevent leakage of fields to the outside environment.

Note that a precision 10 dB attenuator is used with the power detector or spectrum analyzer,

whenever possible, to measure the receiving antenna power. This is done to minimize impedance

mismatch with the receiving antenna. The calibrated bidirectional coupler at the input to the

transmitting antenna allows measurements of the net input power so corrections can be made for

changes in net input power resulting from antenna-rf generator impedance mismatch and rf

generator output variations that occur during the rotation of the tuner. As referred to

earlier, these corrections are made when using the mode tuned measurements approach for each

Incremental change in tuner rotation. For mode stirred, the net input power is measured only

14
at the beginning of the measurement cycle. Details of how the measurement cycle proceeds

under computer control, how the data are managed, recorded, and processed for presentation are contained in the next section describing the software used for these functions.

M.3.2 Software Requirements and Measurement Procedures

The computer code used in the evaluation of the reverberating chamber has evolved from

simple routines that record only the measurement data to the present complex programs that

have abilities to recover from many common system failures and operator errors. The more sophisticated programming is made possible by using modern laboratory computers containing

large amounts of memory. The primary function of recording the measurement data however,

remains unchanged and is outlined in this section, with some discussion of the supporting

activities and refinements.

A general overview of the software is shown in figure 4.2. The major tasks of

accumulating data using the two primary methods (mode tuned and mode stirred), saving the

measured results, and preparing the data graphics are shown. The measurement routines are supported by the module entitled System Calibrations. The data library is not actually

program code, rather it indicates data storage that is available to the Data Graphics program

and is added to by the measurement programs. Two major programs, detailed below, are used to implement the measurement approaches. They are quite different in how the instrumentation is

programmed and the data managed and will be discussed separately. The basic computer code

defining these measurements is listed in appendix A. The listings contain the details of the

measurements as shown in figures 4.3 and 4.4. The instrument control modules have been

omitted to avoid excessive detail.

Mode-Tuned Approach

The flow diagram for the mode-tuned measurement program is given in figure 4.3. This

diagram is used to assist in guiding the operator systematically through the measurement

procedure.

Step 1. Place the EUT inside the chamber and access at as required for operation and

performance monitoring.

Details for placement of the EUT and accessing it are contained in sections 3.1, 4.1, and

4.3.1. The EUT should be placed at least one half meter away from the outer walls of the

chamber unless specified in the test plan to simulate proximity to a ground plane.

Step 2. Connect the measurement system as shown in figure 4.1.

Step 3. Specify measurement and calibration parameters.

Calibration factors for the cables and directional couplers used must first be tabulated

and stored in the computer for later access. All parameters used in the measurements are then

specified using a menu of items from which the operator may select the values for the

experiment. These parameters include: frequency range and increments, number of tuner steps,

signal generator output level as required to obtain the desired field strength inside the

chamber, the EUT output voltage considered as an upper bound for maximum safe EUT operation,

and an estimate of the response time of the EUT. The experiment description, operator's

name, and the system clock can be accessed in the menu also. When the operator is satisfied

with the parameter values and exits the menu, these values plus all calibration values (e.g.,

cable loss, coupling factors, etc.) are tabulated for reference. The measurement hardware is

then initialized and the measurement begins.

Step 4. Perform the measurement (automated measurement sequence).

The measurement sequence can be traced in figure 4.3. At the beginning of each test all

the instruments are set to zero (if there is an internal auto-zeroing feature) or a reading is

taken to determine the offset from zero with the field removed. These offset readings are then used to adjust the readings taken with the field applied. This should be done as often

as needed to minimize errors resulting from zero drift.

It is important to have reached both mechanical and electrical stability at each step of

the tuner before reading the instruments. As the mechanical time constant of the stepping

motor and the chamber's tuner blades is typically much longer than the electrical response

time of the measurement instrumentation or the EUT, the most efficient manner with which to

15
collect the data is to minimize the movements of the tuner. Any given measurement usually

involves a sequence of frequencies at which to measure the response of the device. This

routine is designed to collect the data for all frequencies at each tuner step before moving

the tuner to another location. The data is then rearranged at the conclusion of the

measurements such that data from all tuner positions for a given frequency is together before

it is processed for final graphic presentation.

After the instruments are zeroed and their offset voltages recorded, the rf power is

applied and the response of all devices which could be damaged by excessive field strength is

measured. This checking is done as rapidly as possible for each frequency and provides one

level of protection for the system. Typically, the operator should specify power levels that

are appropriate for the EUT(s) being tested. Then this test will detect only those conditions

which cause an unusually high response.

With the initial checking done, the program then proceeds to read the remaining

instruments in the system. These include power meters, digital voltmeters, spectrum analyzer,

specialized data acquisition systems, and/or any other monitoring device being used.

As mentioned above, all frequencies of interest are measured before the tuner is moved to the next position. There are many possible ways to group this data and save it on a mass storage device. The approach used here is to maintain all the data for a given tuner step (or

several steps) together in one file. This file can then be recalled and the data rearranged

such that all the information for a given frequency is together. Saving the data frequently

allows the measurement to be continued, without starting over, should the system lose power or

a fatal error occur.

The routines necessary for operation of the instruments are, of course, unique to the

device but some general concepts are useful to discuss:

a). The program should exercise some care to insure the validity of the readings. Most

Instruments will allow access to a status byte that will indicate many failures common to the device. This can be monitored during the read cycle and action taken if the

measurement is not valid. Action is also necessary if the device fails to respond or hangs the interface bus. These situations may require operator assistance, but the

program should be able to recover and repeat the operation if the condition is temporary.

b). Readings taken within the limits of the instrument yet too quickly for the rest of the

system to respond, for instance the tuner may still be vibrating or the. sensor may be

slow to respond, will cause erroneous results. For these measurements where the field

being monitored is generated by a cw signal of constant amplitude, the response of a device should settle to a constant value, provided the tuner has stabilized and the

device has had enough time to respond. The computer should be able to determine when to

accept the reading based on the factors mentioned. One method is to install fixed wait

statements that guarantee steady conditions. A more dynamic approach is to monitor the

device and compare readings until steady conditions are reached. This optimizes the

already lengthy measurement by avoiding long idle times that may not be necessary. A refinement to simply comparing readings is to compare the averages of several readings

grouped together, referred to as a running average. This has a tendency to smooth noise

that may be on the signal and also to make comparisons of low level readings (near the

noise floor) more stable.

Step 5. Correct the data by applying the system calibration values and zero field offset

readings.

The correction factors are applied to the measured quantities at the time the data are taken and key items are calculated. These items are then stored in the memory for later use

in compiling the data. Items may include incident and reflected powers to the transmitting

antenna corrected for cable loss and coupling factors, power received from the reference

antenna (corrected), etc. Care must be taken at the beginning of the measurement to assure

that calibration factors and cable loss correction to be used match the physical setup.

At the completion of the last tuner position, with all the data residing in mass storage,

the measurement routine is complete. The remaining tasks are independent programs, freeing

the measurement system for other measurements.

Step 6. Compile the corrected data by frequency, normalize to a constant net input power (for

example 1 watt), perform the statistical calculations and present final results.

16
Normalization of the corrected measurement data for determining: a) the E-field in the

chamber, and b) the EUT response, for a constant net input power is done for each tuner

position. First the corrected net input power is determined and compared to the desired

normalized value. The difference is then used to shift the corrected received power

measurements and EUT response measurements as if the actual net input power had been the

desired normalized value. This may involve a simple linear extrapolation as is the case for

linear detectors, or it may require calibration of the nonlinear response characteristics of

the received power detectors and/or EUT monitors thus resulting in appropriate corresponding

nonlinear corrections.

The statistical calculations are performed using the corrected, normalized data. These

calculations include the maximum, average, and minimum values as appropriate, of the desired

parameters (net input power, received power, EUT output response, etc.). The calculations are made using data sets obtained by using the corrected normalized data at the selected number of

descrete tuner positions for one complete revolution of the tuner, at each frequency of

interest. These result are then, typically, presented in graphs as a function of frequency.

Mode Stirred Approach

The mode-stirred measurement (figure 4.4) begins in a similar manner to the mode-tuned

discussed above. The automated measurements sequence of events is somewhat different and

hence some of the parameters necessary for performing mode-stirred measurements differ from

mode-tuned.

Step 1 . Place EUT inside the chamber and access it as required for operation and performance

monitoring.

This is the same as for mode tuned.

Step 2. Connect the measurement system as shown in figure 4.1

This step is similar to the setup for mode tuned except the spectrum analyzer is used to measure the reference antenna received power and the EUT monitors must be fast sampling

devices such as "smart" voltmeters referred to earlier.

Step 3. Specify measurement and calibration parameters.

These parameters are similar to the mode tuned case with the following two exceptions:

a) The specification of revolution time for the tuner determines the sample size and

sampling parameters associated with the EUT monitoring equipment. Tuner steps

(sampling size) are now given as a function of time for one complete revolution of

the tuner from which the number of samples that will be taken during that single

revolution, for each of the sampling instruments, is determined. These numbers

require careful timing trials prior to automating a mode-stirred measurement. The

instruments used for the tests detailed in this report, "smart" digital voltmeters,

are capable of performing statistical operations on a large number of samples (up to

9999) using a single trigger command. This feature is very convenient for this type

of measurement but requires that the number of samples needed to synchronize rotation

time of the tuner and total sampling time of the voltmeter be known prior to

triggering the measurement. The time required for taking each sample voltage varies

slightly with the amplitude of the signal measured. This makes it difficult to estimate accurately the total time required for any given number of samples.

Approximations are used and the program adjusts the sample count to insure the

correct sampling time for a complete revolution. The sampling should be completed as near to the end of the tuner revolution as possible to avoid weighting the statistics

with an incomplete data set or data taken as the tuner begins a second revolution.

Typical rates for tuner rotation are in the range of 1 to 12 minutes per single

revolution.

b) The signal generator output level is now a range of values because this program has

the ability to search for an optimum response of the device. The range of response

values is also accessible in the mode-stirred menu and gives the operator control

over minimum readable output from the EUT and also the level considered as the upper

safe limit. The program \;ill attempt to keep power levels adjusted such that the

response is at some point above the minimum and never above a maximum.

17
Sometimes it is advantageous to monitor the EUT response using analog devices such as an

xy recorder. If care is taken to insure that the response time of the recorder is short

compared to the sampling rate or rotation rate of the tuner, the EUT output can be monitored

in real time, thus allowing optimization of the sample rate to correspond to the EUT response

time. Care must be taken to insure adequate sample time, otherwise the EUT response will be

clipped yielding inaccurate results. This condition is easy to detect from the analog output

plots and hence avoid.

When the operator is satisfied with the parameter values and exits the menu, these

values plus all calibration values (e.g., cable loss, coupling factors, etc.) are tabulated

for reference. The measurement hardware is then initialized and the measurement begins.

Step k. Perform the measurement (automated measurement sequence)

The measurement sequence is shown in figure 4.^4. At the beginning of each test all the

instruments are set to zero (rf power is off), if possible, or the zero offset is recorded the same as for the mode-tuned approach. The rf power is then applied at the lowest specified

level, the tuner motion is activated, and the EUT response is monitored. This first

measurement attempt, at each specified frequency, results in a search for a threshold response

from the EUT. If the EUT's response is below the preselected level, the rf power is increased

in 1 dB increments and held constant allowing the tuner to rotate a few degrees, while

searching for the threshold level. If the threshold value for the EUT's response is not reached, the generator level is increased again and the searching process repeated until the

threshold level is reached or the maximum range selected for the generator output is achieved.

Upon finding an acceptable power level, the instruments are triggered to begin a measurement

cycle. Typically the instruments used include "smart" digital voltmeters as mentioned earlier

and a spectrum analyzer looking for a peak response from the reference antenna. Any

specialized detecting device would also be included. The response of the EUT is constantly

monitored via a second fast sampling voltmeter (in addition to the "smart" voltmeter doing the

statistics) to protect it from overload. If, during the test, the response should exceed the

maximum safe value so that the power level is decreased or any other error condition is

detected, the program will remember the correct power level to be used as the measurement is

restarted.

At the time all the instruments are done sampling, the program checks to see if the tuner completed a full revolution before the measurements (sample) were finished. A comparison of

the times taken for the tuner revolution and each meter's total sampling time is made. If these values agree to within a given tolerance and no other errors were detected, then the

numbers are assumed to represent a valid measurement. On the other hand, if these conditions

are not met, the sampling parameters are adjusted and the entire measurement process is

repeated for the same frequency. Special care taken in the preparation of these sample

parameters, as mentioned earlier, will minimize the need for repeat measurements.

The results from all the instruments are now read into the computer, corrected using the

appropriate calibration factors and the necessary calculations are made. This includes the

statistical parameters for the EUT monitored data, as determined by the "smart" voltmeters,

and the peak value of the received power from the reference antenna as measured using the

spectrum analyzer. Caution must be exercised if the test field is modulated since this may

influence the accuracy of the measurement results depending upon the detector (s) response

characteristics.. The reference antenna received power data can be used to determine a normalized response for the EUT based upon a constant test field level as a function of

frequency if desired. The net input power delivered to the chamber is measured after the

acceptable power level is established at the beginning of the measurement cycle, just prior to triggering the "smart" voltmeters. These measurements may then be used to normalize the data

to an equivalent constant input power level preselected for all test frequencies if desired.

The entire process is then repeated until all frequencies have been measured.

The process by which the statistics are derived for the parameters monitored by the

"smart voltmeters" consists of the following steps: 1) the measured analog data is converted

to digital form; 2) the first data value is stored for future reference; 3) the second and

subsequence data values are compared to the previous data values to determine maximum,

minimum, and the running total values; ^J ) at the conclusion of the data collection,

(completion of the data sample) the running total is divided by the sample size to calculate

an average value for the data set; and 5) finally, the maximum, minimum, and average values

stored in the "smart" voltmeter are transferred upon command to the computer for mass storage

and future use as required.
step 5. Compile the corrected data and present final results.

Data obtained using the mode stirring approach is not normalized at each tuner position.

Corrections applied to this data to normalize it to a specified value of net input power must

be applied to the maximum, average, and minimum values as determined by the "smart" voltmeters

( EUT and other monitored responses) or the maximum value (reference received power) as determined by the spectrum analyzer. Correction made to the data for cable loss, etc., must

also be made in a similar way. After these corrections are made, the data is compiled by

frequency and presented typically in graph form usually showing only the maximum values as a function of frequency. For example see figures 5.15 and 5.16.

5. Experimental Test Results

5.1 Correlation of Results to Anechoic Chamber Tests - Some Examples

This section describes efforts to estimate a "correlation factor" between reverberation

chamber and anechoic chamber obtained results. This was done first for reference standard

EUTs and then for an EUT more typical of operational equipment. Tests were performed using

the NBS reverberation chamber and a 4.9 m x 6.7 m x 8.5 m anechoic chamber also located at NBS. The EUTs included in this study are: 1) a one centimeter dipole probe antenna (200 MHz

to 18 GHz), 2) a ridged horn antenna (800 MHz to 10 GHz), 3) a series of rectangular coaxial

transmission line (TEM) cells with apertures, (200 MHz to 4000 MHz), and 4) a modified 7.0 cm

(2.75 ") folded fin aircraft rocket, (FFAR) (200 MHz to 12.0 GHz).

5.1.1 Description of Anechoic Chamber Measurement System

A block diagram of the NBS anechoic chamber EMC measurement system is shown in figure

5.1. The test field is established inside the chamber by means of an rf source connected to a standard gain transmitting antenna. This "standard field" is computed from [22]

30 Pnet^ , (14)

where P is the net power in watts delivered to the transmitting antenna, G is the effective

gain for the transmitting antenna, and D is the separation distance in meters. Equation (14) assumes far-field conditions for a field point on axis of the transmitting antenna so that G is the maximum power gain.

The net power, P ^, is determined using calibrated power meters and bidirectional

net ^ ^ couplers from the expression

P ^ = P. CR^ - P ^ CR„ (15) net inc F ref R

where P. is the forward incident power, P ^ is the reverse reflected power measured on the inc ^ ref

sidearm of the coupler, and CR„ and CR„ are the forward and reverse coupling ratios for the

r ri coupler referenced to its output port.

The transmitting antennas used are open ended waveguides (200 to 500 MHz) and standard

gain horns (500 MHz to 18 GHz).

Comparisons of the response or susceptibility characteristics of EUT (or antennas)

obtained using an anechoic chamber and a reverberation chamber are typically made in terms of

peak values. The main reasons for this are that typically the EUT's worst case performance or susceptibility is desired, and the practical consideration of the difficulty in obtaining a true average response for an EUT from anechoic chamber data. Even determining the EUT's peak

response in an anechoic chamber (depending of course upon how well behaved the EUT radiation

pattern characteristic is) can require considerable measurements involving complete pattern

measurements.

5.1.2 Measurement of the Peak Response of a 1 cm Dipole and a Ridged Horn

A comparison of the peak output response data obtained for the 1 . cm dipole using the

NBS reverberation and anechoic chambers is given in figure 5.2. Note that the probe output

response in the anechoic chamber is greater, in general, by about 2.5 dB than its output in

19
the reverberation chamber. This suggests that the correlation between the results may be

related to the EUT's gain characteristics in the two chambers (i.e., the gain of the dipole

probe in free space is approximately 2.5 dB) . Determination of a far-field gain for a complex

receptor (for example the EUT described in section k.3.^) is extremely difficult. Therefore,

a simple, well defined broadband receiving antenna (a ridged horn) was used as an EUT to repeat similar tests performed for the 1 cm dipole. The horn is designed to operate in the

frequency range 800 MHz - 10 GHz. For these measurements in the anechoic chamber, the peak

response (peak received power) of the horn occurs when the horn is bore-site aligned and

polarization matched with the source antenna. These measurement results were then compared

with the horn's peak received power in the reverberation chamber with the same level exposure

field. The results are shown in figure 5.3a. Note that the horn's response is greater in the

anechoic chamber. To see if this difference corresponded to the difference in the gain

characteristics of the horn in the anechoic chamber, as compared to that in the reverberation

chamber, the horn was calibrated to determine its far-field gain in the frequency range 800

MHz - 10 GHz. These results are shown in figure 5.3b. Again, note the general agreement

between the difference in the horn's response measured in the two facilities and the horn's

far-field gain.

5.1.3 Measurement of RF Coupling Through Apertures in TEM Lines

Measurements were made using the reverberation and anechoic chambers to evaluate the rf

coupling through apertures cut into a series of TEM cells or transmission lines. Three TEM

cells were used. Similar models (EUTs) have been used for evaluating shielding effectiveness

of connector assemblies [23]. Electromagnetic energy coupled through the aperture in the TEM

cell when exposed to the test field excites the fundamental TEM mode inside the cell. This

results in rf power conducted to the cell's output ports which can then be measured. These

results are compared with the theoretically predicted values based upon a planar field

exposure to determine degree of correlation. The results obtained for one of the TEM cells,

shown in the photograph of figure 5.4, are given in figure 5.5. The dimensions for this cell are 12 cm x 1 8 cm x 36 cm with a 5.1 cm x 5.1 cm aperture centered in the top of the outer

conductor. The theoretically predicted peak coupling for a uniform field exposure is also

shown on figure 5.5 [2M]. Measurements were not made in the anechoic chamber at frequencies

below 500 MHz because of the limitations of the anechoic chamber measurement system. The

theoretical peak values should be essentially the same as the measured values in the anechoic

chamber. Again, the anechoic chamber peak data are generally higher than the peak

reverberation chamber data. Also, the average reverberation chamber data are approximately 7-8

dB lower than the peak data, similar to both the 1 cm dipole and ridged horn results.

Results obtained for the second cell, shown in figure 5.6, are given in figure 5.7. The

dimensions for this cell are 1 2 cm x 1 2 cm x 24 cm with a 3.1 cm diameter aperture. The

results are similar to those shown for the larger cell. Results obtained for the third cell,

shown in figure 5.8, are given in figure 5.9. The dimensions for this cell are 3-0 cm x 6.0 cm X 11.4 cm with a 1.4 cm diameter aperture centered in the top of the outer conductor.

Again the results are similar.

5.1.4 Measurements of the EM Susceptibility of a Modified 7.0 cm Folding Fin Aircraft Rocket

(FFAR) [25].

A 7.0 cm diameter FFAR was modified with a thermocouple element to sense the response of

the rocket's inserted electro-explosive device (EED). This was done to allow measurement of

the rf current coupling into the EED's bridge wire circuit when the rocket is exposed to an rf

field. The rocket was also modified with a 1.27 cm plastic spacer at the base of its fin (on

the tail section) to increase the rf coupling to the bridge wire circuit. This lessened the

requirements for high rf power to generate fields sufficient to perform these measurements.

This modification was justified, realizing the purpose of this study was to compare

susceptibility results obtained for the rocket in different environments and not to simply

evaluate an EUT's susceptibility to EMI. Photographs showing the rocket placement inside the

NBS reverberation chamber and the NBS anechoic chamber are shown in figures 5.10 and 5.11.

Measurement results of the rocket's thermocouple peak output current resulting from rf

coupling as a function of frequency are shown in figures 5.12a and 5.12b. These data were obtained using exposure fields normalized to 10 mW/cm^ in each of the chambers. The anechoic

chamber data were obtained by rotating the rocket in azimuth in a planar far-field using both

vertical and horizontal polarizations. The rocket was rolled a few degrees around its axis

before each azimuth cut. Sufficient roll angles were used to determine the peak response.

Examples of pattern data obtained in the anechoic chamber at three selected frequencies -are shown in figure 5.13. A total of 719 patterns were obtained in the anechoic chamber from

20
which the peak response at each frequency was determined. These data were then used to plot curve A of figure 5.12a. Curve A (anechoic chamber data) indicated greater response or more

susceptibility, except at one frequency (I8OO MHz), than curve B (reverberation chamber peak

response). Again, the proposed explanation for this is the difference between the gain

characteristics of the rocket's response in the anechoic chamber (for example see figure 5.13)

and its gain characteristics in the reverberation chamber. The rocket gain is lost in the

reverberation chamber. Figure 5.12b shows the difference between curves A and B for figure

5.12a.

5.2 Comparison of Results Between Reverberation Chambers

Measurements were made of the EM susceptibility response of three different EUTs, using

two additional, similar, but different size reverberation chambers. These measurements were

made to give an indication of the repeatability in measurement results obtained using the same technique (reverberation chamber methods) but with totally different facilities. The second

and third reverberation chambers are located at the Naval Surface Weapons Center, Dahlgren,

Virginia. These chambers were made from a single large shielded enclosure partitioned into

two compartments with a removable center panel. The two chambers consist of: 1) the half

chamber, 3-51 m x 5.18 m x 5.86 m in size using a little over half of the full enclosure, and

2) the full chamber, 3.51 m x 5.18 m x 10.82 m in size, using the full enclosure. The NSWC

enclosure was constructed of continuously welded steel sheeting similar to the NBS enclosure.

Two basic insights are provided by a comparison of results obtained from the evaluation of

these different enclosures. First, that the input power requirements of a chamber is a function of its size and can be estimated based upon the calibration of a chamber of similar

construction. Second, susceptibility test results obtained for the same EUT in different

reverberation chambers are comparable. These conclusions are demonstrated in figures 5.1^ to 5.17. Figure 5.1^ shows a comparison of the fields inside the NBS and NSWC chambers

calculated from the chamber's reference antenna received power measurements and then measured

by a calibrated 1 cm dipole probe. The net input power was normalized to one watt for all

three chambers. Note that the field Inside the NBS chamber is approximately 4 dB stronger

than the NSWC half chamber and 6 dB stronger than the NSWC full chamber. Recall that the

power density inside a second chamber can be estimated from a calibrated chamber by using (9).

The ratio of the average power densities for the NBS to NSWC full size chamber for the same

net input power (see section 2.1) was 3.22. This is equal to approximately 5 dB, a little

less than that indicated by comparing figures 5.1 4a and 5.1 4c, but still within reason.

The second point of obtaining comparable susceptibility results using different chambers

is demonstrated in figures 5.15 to 5.17. These graphs show the comparison in measuring the

responses of the NBS 1 cm dipole probe and a rectangular single ridged horn to a normalized 37 dB V/m field inside the three different chambers and the peak response of the 7.0 cm FFAR to a normalized 10 mW/cm^ power density inside the NBS and the NSWC half size reverberation

chambers. In general, the agreement is within measurement tolerances except at 200 MHz for

the FFAR. This frequency approaches the lower limit for using the reverberation chambers and

is also where the FFAR is most susceptible and hence where one would expect the greatest

difference.

6. Summary and Conclusions

6.1 Conclusions Drawn From Study

1

.

The practical lower frequency limit for using the NBS enclosure as a reverberation chamber

is approximately 200 MHz. This lower limit is due to a number of factors including

insufficient mode density, limited tuner effectiveness, and ability to uniformly excite

all modes in the chamber. These factors are a function of both chamber geometry and size.

Increasing the inside dimensions of the chamber will lower the useful frequency limit in an approximately proportional manner.

2. Spatial variations in the E-field maximum and average values determined in the chamber's

test volume are:

Frequency (MHz) Variation in Measured E-Field

200 <± 8 dB

500 <± 5 dB

1000 <± 3 dB

2000 <± 2 dB

21
These data were determined using the mode tuned approach with 200 tuner increments for one complete tuner revolution. The limitation for determining the spatial E-field variation is

most likely due to the increasing mode density and hence field complexity in the chamber as a function of frequency and the insufficient sampling of the field resulting from the limited

number of tuner positions used. The spatial E-field variations should decrease less than 2 dB

at frequencies above 2 GHz if sufficiently large data samples are taken.

3. Using a combination of antennas within their specified design frequency ranges for

transmitting and as reference receiving antennas inside the chamber is preferred to the use of a long wire antenna. This is apparent because of the lower VSWR and greater

efficiency in exciting the chamber and coupling energy from the chamber.

4. E-field data obtained using the mode stirred approach with the chamber empty have

significantly less amplitude variations with frequency than data obtained using the mode

tuned approach, particularly at frequencies above 1-2 GHz (e.g., <3 dB rather than <6 dB. Compare figure 2.26 to figure 3.3.) This implies that the mode stirring method is

superior for some applications above these frequencies. This is significant since the

stirred method is much simpler and faster to use. In comparing the two methods it is

interesting to note the difference in the amplitude of the maximum fields at frequencies

below 1-2 GHz. The mode tuned method is more accurate at these frequencies for

determining the absolute amplitude of the test field since it allows for corrections due

to changes in antenna VSWR. Because of these observations and other supporting data, the

best results (accuracy versus measurement time considerations) for the NBS reverberation

chamber can be obtained using the following approaches and tuner positions for

susceptibility testing:

Frequency Range Method # Tuner Positions or Samples

0.2-1.0 GHz Mode Tuned 200

1.0-2.0 GHz Mode Tuned 400

>2.0 GHz Mode Stirred 5000

5. Lowering the Q of the enclosure: a) increases the rf power required to obtain the test

field, b) increases the uncertainty in determining the test field level, and c) decreases

the spatial, statistical field uniformity.

6. The statistically determined average wave impedance of the EM field in the chamber is

approximately that of free space (377 ohms), thus confirming the validity of (10).

7. The maximum E-field is approximately 7 to 8 dB greater than the average E-field.

8. Scattering from the EUT does not seem to influence the statistical, spatial E-field

distribution within the chamber.

9. Multiple source excitation (from more than one location) improves the spatial E-field

distribution slightly, but not enough to justify additional hardware requirements and the

additional rf power needed to compensate for the loss in the additional input transmission

line required.

10. Energy is conserved in the chamber (i.e., power coupled from the chamber via loss in

transmission lines, antennas, EUT, physical support materials, etc., reduce the power

density in the chamber. Thus it is good practice to remove all that are not essential to the tests from the chamber.

11. The chamber (NBS) continues to operate (as a reverberation chamber) with loading that

reduces the Q significantly (up to 90? of the total energy absorbed), however, with

significant loss in measurement accuracy.

6.2 Summary of Measurement Uncertainties

6.2.1 Determining the Field Strength Inside the Chamber

Recall from section 2.3.1 that the susceptiblity/ vulnerability test field established

inside the chamber can be expressed either in terms of an "equivalent" power density (8) or an "equivalent" E-field strength (10). An estimate of the uncertainties in each of these

quantities can be obtained by analyzing the contributing parameters involved in each

22
mode-tuned and mode stirred approaches respectively, within their appropriate frequency bands.

Five major categories are identified. The first is the uncertainty in determining the

received power from the chamber's reference antenna. This is broken up into four components:

namely, cable loss, attenuator calibration, reference antenna efficiency and power meter or spectrum analyzer measurements uncertainties. Values shown are typical of estimated

uncertainties stated for these type of measurements and instruments.

The second category is the impedance mismatch error that can occur between the reference

receiving antenna(s) (source) and the power detector(s) (load). The actual power delivered to the load is a function of the impedance match between the source and load, with maximum power

transfer occurring when a conjugate impedance match exists.

Power transfer between a source and a load is given as

fraction of maximum (1 - |r„|^) (1 - |r.|^)

P = available power absorbed = (15)

by the load |l - T„T. \ ^ O Li

where r„ and r denote complex reflection coefficients. The magnitudes, |r-| and Ir I can be

O Li O Lt Obtained from the appropriate VSWR by the expressions

I . I VSWR - 1 . ^ , \'i\ = VSWR ^ 1

' 1 = S or L .

The VSWRs for the reference antennas (sources) and power detectors (loads) used in the

NBS reverberation chamber are given in table 6.3. These values were used to calculate the

estimated uncertainties shown for the mismatch error in tables 6.1 and 6.2. Note that

different average and maximum values are given.

The third category of error, referred to as mixing or sampling efficiency, is divided

into two parts. The first part relates to the ability to obtain a uniform spatial field

distribution (statistically) inside the chamber and to effectively destroy the polarization

characteristics of the exposure field, (i.e., the statistically determined response

characteristics of the EUT and chamber reference antenna are independent of their directional

properties.) The second part is the uncertainty due to limiting the number of tuner positions

per revolution when performing the measurement. This source of uncertainty is different when

determining the average as compared to the maximum field as shown in the tables. Data shown

in figure 2.27 and table 6.M were used in obtaining these estimates.

The fourth category of uncertainty relates only to determining the equivalent E-field

strength in the chamber from the equivalent power density. Recall that (10) assumes that the

equivalent wave impedance inside the chamber is 120ir ohms. In reality this is not true as was shown in figure 2.25. This figure was then used to provide an estimate for this error taking

into account that a significant amount of data obtained to date indicates that peak fields are approximately 7-8 dB greater than the average field strength inside the chamber (see section

2.3.2). i.e., An examination of figure 2.25 shows values of wave impedance as large as 1 600

ohms at frequencies below 500 MHz when the maximum E-field was measured. This would require a large correction, up to 6.3 dB. However, experience indicates that a well behaved

relationship (7-8 dB difference) exists between the measured peak and average values of the E- field. This suggests that the peak value of the wave impedance for maximum E-field inside the

chamber decreases as the frequency increases thus lowering this source of error. These

observations are reflected in the uncertainty estimates shown in the tables.

The fifth source of error occurs If one fails to correct for net input power variations

due to the loading effect of the chamber on the VSWR of the source antennas. (See section ^.2

for more details.) Note that these corrections are made typically when using the mode tuned

approach and hence are not included in the total or root-sum-square error estimates of table

6.1. They are shown on the table to provide insight to the estimated magnitude of error expected if this correction were not made. The basis for these estimates are the data shown

in figures 6.1a and 6.1b. These figures show the average and maximum E-field strength

measured inside the NBS reverberation chamber using an array of seven NBS isotropic probes. A comparison is shown between results obtained before and after the measurements were corrected

for net input power variations and normalized for an equivalent constant net input power.

Note from table 6.1 this error is the same order of magnitude as 2), the mismatch error between the receiving antennas and power detectors. This is as expected since the source and

23
receiving antennas used in the chamber have similar VSWRs and the power detector (load) and

generator VSWRs are also similar. This error is included in table 6.2 and estimated to be the same as for the receiving mismatch error.

The total (worst-case) uncertainties for each approach (mode-tuned, and mode-stirred) are shown at the bottom of each table. This uncertainty should be regarded as a conservative

estimate. The probability of the true value of E being near the extreme of such worst-case

uncertainty is small. This is because the probability of every error source being at its

extreme value and in the worst possible combination is almost zero.

A more realistic method of combining uncertainties is the root-sum-of-the-squar es (rss)

method. The rss uncertainty is based on the fact that most of the errors are independent of

each other and hence are random with respect to each other and combine like random variables.

The rss method of combining random variables is justified by statistical considerations

(beyond the scope of this report) which are also inherent in the reverberation chamber

measurement methods.

Finding the rss uncertainty requires that each individual uncertainty be expressed in

fractional form. The method of calculation follows the name - square the components, sum those squares and then take the square root. The results are shown at the bottom of tables

6. 1 and 6.2.

6.2.2 General Comments on Error Analysis.

Some general comments on interpreting immunity measurement results uncertainties based

upon the above experimental error analysis are appropriate.

1) The mismatch error at frequencies below 2 GHz, (particularly if corrections are not made

for either the transmitting antennas or the receiving antennas mismatch looking into their source or load), will cause the field determination inside the chamber to be low. This

also causes the EUT response results to be lower than they actually are. For example, the

low frequency data of figures 5.15, 1 cm dipole, and 5.16, ridged horn, should be

corrected (response increased) proportionally to the systematic offset error estimates

show in tables 6.1 and 6.2. (i.e., 3.'16 dB at 1.0 GHz and 1.66 dB at 2.0 GHz).

2) The wave impedance, when the peak response of an EUT is measured, appears to be higher

than 120Tr ohms. This means that if the free space wave impedance of 1 20ir ohms is used in

determining the corresponding peak amplitude of the exposure field, there will be a systematic offset error resulting in too low a calculated E-field exposure value, or, since the actual E-field is higher than the calculated value this results in too high a EUT response indication for a specified E-field exposure.

3) The spatial variation in the measured, statistically determined E-field in the chamber

resulting from a complete revolution of the tuner decreases from as great as ± 8 dB at 200

MHz down to less than ± 2 dB at 2.0 GHz. (See figure 2.27.) Logically, it is expected

that this variation will continue to decrease as the frequency increases. However, high

variations exist in the response data obtained for EUT at frequencies where the spatial E- field variations are small. This is probably due to the relatively large variations in

the wave impedance as a function of tuner position. Some additional influence may be due to the mismatch characteristics of the antennas vs source and load as a function of

frequency. A way to reduce this problem is to increase the number of frequencies at which

data are taken (clustered around a particular frequency of interest) or increase the

number of reference receiving antennas or probes used to determine the exposure field (for

example see figure 2.27) and then average the data.

6.3 Measurement Technique Advantages and Limitations

Significant advantages do exist, as alluded to in the introduction, for using a reverberation chamber for EMC measurements. Specific advantages and limitations for which

insight was obtain from this study include:

a) The ability to generate high level fields efficiently. For example, 1 watt net input

power into the NBS reverberation chamber results in electric fields of approximately 70 V/m. This is approximately 1/10 the input power required to generate the same level field

in the NBS anechoic chamber, assuming far-field separation distances.

24
b) Large test zones, for example up to 2/3 of the volume inside a reverberation chamber can

be available excluding an area approximately 1/2 meter spacing to the walls.

c) Broad frequency coverage (from 200 MHz to at least 18 GHz in the NBS chamber).

d) Testing is cost effective. This is especially true in comparison to anechoic chamber

testing. Significant savings are realized in two major ways. First, the facility

installation and measurement system procurement costs for a reverberation chamber are significantly less than for an anechoic chamber. Second, the time required to perform a complete EMC analysis of an EUT should be much less using a reverberation chamber. Again,

from our experience in evaluating the susceptibility of the 7.0 cm FFAR, it required

approximately 1/10 the test time to obtain the reverberation chamber results as compared

to the anechoic chamber results shown on figure 5.13.

e) The directional characteristics of antenna or EUT placed inside a reverberation chamber

are lost resulting in an equivalent gain of unity.

f) The response of an antenna or EUT measured inside a reverberation chamber Is less than

when measured inside an anechoic chamber (open space) in proportion to its gain. Hence,

it appears that the EUT's gain is the desired correlation factor. This implies that

susceptibility criteria determined for an EUT using a reverberation chamber must include

an additional factor proportional to the EUT's estimated maximum gain as a function of

frequency.

g) The response of EUT to an electromagnetic field after it has penetrated the EUT's shield,

appears to be equivalent in both the reverberation and anechoic chambers.

The advantages indicated above may well outweigh the disadvantages implied in items e and

f, at least for some applications. The obvious trade off is one of measurement uncertainty

that one can tolerate in determining the EMC/EMI characteristics of specific EUT and the

inherent measurement uncertainties associated with determining the amplitude of the test

fields inside the reverberation chamber.

7. Suggestions for Future Research Efforts

Because of the significant potential of the reverberation chamber method for performing

immunity measurements, considerable interest has been expressed to further evaluate this

technique with the intent of extending its range of applications. Specifically, the following

suggestions are offered.

1) Evaluate the reverberation chamber measurement method for pulsed rf (down to 1 ps pulse

duration) immunity testing, (i.e., experimentally investigate pulse dispersion

characteristics of the chamber). Measurement studies are in progress at NBS under the

sponsorship of the NSWC and RADC to complete this task.

2) Determine the feasibility of extending the use of the chamber from 18 GHz to 40 GHz. A plan exists to undertake such an effort in late 1985 at NBS under sponsorship of RADC.

3) Evaluate reverberation chamber excited as a TEM transducer, (i.e., determine the

feasibility of consolidating a TEM cell and reverberation chamber into a single facility

for testing from 10 kHz to 18 GHz and beyond). This item is suggested because of the

unique potential of developing a single, shielded facility that could be used for EMC/EMV

testing over the complete frequency range listed above. This task is also planned at NBS

under RADC sponsorship.

4) Investigate the feasibility of using the reverberation chamber for multiple frequency

immunity testing. This is of interest because such complex fields of multiple frequencies

can exist in typical operational environments.

5) Investigate the use of the reverberation chamber technique for measuring shielding

effectiveness of connectors (evaluate MIL STD 13'*'^ measurement technique), shielding

materials, and enclosures in comparison to other techniques. This suggestion is included

with the objective of improving the state of art in shielding measurements and to

determine if correlation or agreement exists between results obtained using the

reverberation chamber method and other established techniques.

25
8.0 Acknowledgments

The work described in this report was jointly funded by the Naval Surface Weapons Center

( NSWC ) , Dahlgren, Virginia; Rome Air Development Center (RADC), Griffiss Air Force Base,

Rome, New York; and the National Bureau of Standards , (NBS) , Boulder, Colorado. The authors

express appreciation especially to John Bean, NSWC; Charles Blank, RADC; and Mark T. Ma, NBS

for their support, helpful comments and editorial review. Acknowledgement is also given to

John L. Workman for his assistance in performing many of the measurements included in this

study.

9.0 References

[I] Mendes, H,A. A new approach to electromagnetic field-strength measurements in shielded

enclosures, in Wescon Tech. Papers; Los Angeles, CA. 1968 August.

[2] Cummings, J.R. Translational electromagnetic environment chamber, a new method for

measuring radiated susceptibility and emissions. Proc. IEEE Int. Symp. on EMC; 1975;

San Antonio, Texas.

[3] Corona, P; Latmiral, G; Paolini E; Piccioli L. Performance of a reverberating enclosure

for power measurements in the microwave range. 2nd Symp. Tech. Exhibition on EMC; 1977;

Montreux, Switzerland. 419-M27.

[4] Bean, J.L.; Hall, R.A. Electromagnetic susceptibility measurements using a mode-stirred

chamber. Proc. IEEE Int. Symp. on EMC; 1978; Atlanta, GA.

[5] Corona, P. Electromagnetic reverberating enclosures: behavior and applications. Alta.

Frequ.: Vol. 49; 1980. 154-158.

[6] Corona, P.; Latmiral, G; and Paolini, E. Performance and analysis of a reverberating

enclosure with variable geometry. IEEE. Trans, on EMC; EMC-22(1): 2-5; 1980 February.

[7] Crawford, M.L. Evaluation of a reverberating chamber facility for performing EM

radiated field susceptibility measurements. Nat. Bur. Stand. (U.S.) NBSIR 8I-I638; 1981 February.

[8] Liu, B.H.; Chang, D.C.; and Ma, M.T. Eigenmodes and the composite quality factor of a reverberating chamber. Nat. Bur. Stand. (U.S.) NBS Tech. Note IO66; 1983 August.

[9] Ramo, S. ; and Whinnery, J.R. Fields and Waves in Modern Radio, 2nd ed. New York: John

Wiley & Son, Inc.; I960. 418-428.

[10] Liu, B.H.; Chang, D.C.; and Ma, M.T. Design considerations of reverberating chambers

for electromagnetic Interference measurements. Proc. IEEE. Int Symp. on EMC;

1983; Washington, DC. 508-512.

[II] Ma, M.T.; Kanda, M.; Crawford, M.L.; and Larsen, E.B. A review of electromagnetic

compatibil ity/ interference measurement methodologies. Proc of IEEE. 388-411; 1985

March.

[12] Tai , C.T, On the definition of the effective aperture of antennas. IEEE Trans.

Antennas and Propag. AP-9: 224-225; 1961 March.

[13] Greene, F.M. Development of Electric and Magnetic Near-Field Probes. Nat. Bur. Stand.

(U.S.) NBS Tech. Note 658; 1975 January.

[14] Roe, J.M. An improved technological basis for radiated susceptibility and emissions

specifications. Proc. IEEE. Int. Symp. on EMC; 1978; Atlanta, GA.

[15] Roe, J.M. Design of tuner for TEMEC, McDonnel Douglas Corp., St. Louis, MO., Private

Communication.

[16] Bean, J.L. Design of tuner for NSWC reverberating chamber. Naval Surface Weapons

Center, Dahlgren, VA. , Private communication.

26
[17] MIL-STD-1377 (Navy). Effectiveness of Cables, Connectors, and Weapons Enclosures

Shielding and Filters in Precluding Hazards of Electromagnetic Radiation to Ordinance,

Measurement of. 1971 August.

[18] Lentz, R. ; and Anderson, H. Reverberating chambers for EMC measurements. Proc. IEEE. Symp. on EMC; 1979; San Diego, CA.

[19] Crawford, M.L. and Koepke, G.H. Operational considerations of a reverberation chamber

for EMC immunity measurements - some experimental results. Proc. IEEE. Nat. Symp. on

EMC; 1984; San Antonio, TX.

[20] Wilson, P.F. Peak versus average response characteristics in a reverberation chamber.

National Bureau of Standards, Boulder, CO, Private communication.

[21] Bensema, W.D.; Reeve, G.R.; and Koepke, G.H. A multisensor automated EM field

measurement system. Proc. IEEE IMTC/85 Conf; 1985; Tampa, FL.

[22] Bowman, R.R. Calibration techniques for electromagnetic hazard meters: 500 MHz to 20

GHz. Nat. Bur. Stand. (U.S.) NBSIR 75-805; 1976 April.

[23] Pressel, P.I. Mismatch: a major source of error in shielding effectiveness

measurements. Proc. Seventeenth Annual Connector and Interconnection Technology Symp;

1984 September; Anaheim, CA.

[24] Wilson, P.F. Apertured coaxial probe. Paper in progress.

[25] Bean, J.L. Hero susceptibility of a 2.75 Inch FFAR: comparative results obtained from

mode-stirred chambers, anechoic chamber, and ground plane test facilities, Proc. IEEE IMTC/85; 1985; Tampa, FL.

27
LIST OF FIGURES and TABLES

Figure 2.1. Distinct frequencies of modes in NBS 3.05 m wide x M.57 m long x 2.7M m high

shielded chamber below 200 MHz.

Figure 2.2 Total number of modes as a function of operating frequency for the NBS chamber.

Figure 2.3 Total number of modes as a function of operating frequency for a square based

chamber whose volume is the same as that of NBS chamber.

Figure 2.4 Total number of modes as a function of operating frequency for a cubic chamber

whose volume is the same as that of NBS chamber.

Figure 2.5 An illustration of mode degeneracy (NBS chamber).

Figure 2.6 An illustration of mode degeneracy (square-based chamber).

Figure 2.7 An illustration of mode degeneracy (cubic chamber).

Figure 2.8 Cumulative distribution curve of the normalized 1 /Q values in the 1 80 MHz to 200

MHz frequency band for the NBS chamber.

Figure 2.9 Cumulative distribution curve of the normalized 1 /Q values in the 330 MHz to 350

MHz frequency band for the NBS chamber.

Figure 2.10 Cumulative distribution curve of the normalized 1 /Q values in the 480 MHz to 500

MHz frequency band for the NBS chamber.

Figure 2.11 Photograph of interior of NBS reverberation chamber.

Figure 2.12 Average and minimum losses between transmitted and received powers measured at antennas' terminals inside NBS reverberation chamber. Transmitting antennas are: log periodic (200 MHz - 1000 MHz), ridged horn (1.0 GHz - 4.0 GHz), double

ridged circular horn (4.0 GHz - 18 GHz). Receiving antennas are: long wire (200

MHz - 1000 MHz), ridged horn (1.0 GHz - 4.0 GHz), double ridged circular horn

(4.0 GHz - 18 GHz).

Figure 2.13 Theoretical composite Q and experimental Q' determined for NBS reverberation

chamber, a) Theoretical and experimental values of Q as a function of frequency.

b) Ratio of the theoretical composite Q to experimental Q' as a function of

frequency.

Figure 2.14 Bulkhead panel used for accessing NBS reverberation chamber.

Figure 2.15 Tuner designs for use in reverberation chambers. a) McDonnell Douglas Corp.

TEMEC tuner, b) NSWC chamber tuner, c) NBS chamber tuner.

Figure 2.16 Photograph of tuner, log-periodic transmitting antenna and NBS Isotropic probes

inside NBS reverberation chamber.

Figure 2.17 Details of tuner and stepping motor mounting for the NBS reverberation chamber.

Figure 2.18 Ratio of maximum to minimum received power obtained by rotating tuner in the

frequency range 200 MHz to 18 GHz. a) Empty chamber, b) Four pieces of 66 cm rf

absorber placed upright in center of chamber, 0.5 m above floor.

Figure 2.19 Cross sectional views of NBS reverberation chamber showing placement of tuner,

transmitting and receiving antennas, and NBS probes.

Figure 2.20 Design of taper section of long wire antenna for use in Reverberation chamber.

Figure 2.21 Photograph showing long wire antenna and NBS probes placement inside NBS

reverberation chamber.

28
Figure 2.22 VSWR of transmitting antennas placed inside NBS reverberation chamber, a) Long

wire antenna, chamber empty, b) Composite of three antennas , (log-periodic , 0.2-

1.0 GHz), (ridged horn ,1.0 - 4.0 GHz), and (double ridged circular horn, 4.0-18

GHz), chamber empty, and c) Composite of three antennas with chamber loaded with

4 pieces of 66 cm rf absorber placed upright in center of chamber, 0.5 m above

floor.

Figure 2.23 Average and minimum losses between transmitted and received powers measured at antennas's terminals inside NBS reverberation chamber. Long wire antenna

transmitting (200 MHz - 18 GHz), composite of three antennairecei ving (log

periodic 200 MHz - 1000 MHz, ridged horn, 1.0 GHz - 4.0 GHz, double ridged

circular horn, 4.0 GHz - 18 GHz).

Figure 2.24 Average and minimum losses between transmitted and received powers measured at antennas' terminals inside NBS chamber with four pieces of 66 cm rf absorber

upright in center of chamber, 0.5 m above floor. Composite of three antennas

used for transmitting and receiving.

Figure 2.25 Magnitude of wave impedance inside NBS reverberation chamber.

Figure 2.26 Average and maximum E-field strengths inside empty NBS reverberation chamber for

1 W net input power determined from: a) composite of 3 antennas received power

measurements, and b) calibrated 1 cm dipole probe measurements.

Figure 2.27 E-field strength measured inside NBS reverberation chamber using array of 7 NBS

isotropic probes: (a) maximum, and (b) average. Net power normalized to 1 Watt. Transmitting antennas are: log periodic (100 MHz - 1 GHz), ridged horn (1 GHz - 2 GHz).

Figure 2.28 Mean values of the E-field strength measured inside NBS reverberation chamber

using array of 7 NBS isotropic probes with 1 W net input power: (a) average, and

(b) maximum. Data determined from maximum and average values of the 7 probes (7

locations) for the three orthogonal components and their sum (total) using 200

tuner positions (1.8 degree increments).

Figure 3.1 Placement of metallic objects inside NBS reverberation chamber to evaluate

scattering effects upon E-field spatial distribution, a) Photograph showing 30 cm x 50 cm X 60 cm welded aluminum box inside NBS reverberation chamber, b)

Photograph showing rolling equipment rack inside NBS reverberation chamber.

Figure 3-2 Comparison of the mean value of the average and maximum E-field strength measured

using array of probes placed inside NBS reverberation chamber with chamber empty

or with scattering object placed at center of test zone, a) 30 cm x 50 cm x 60 cm aluminum box, b) Rolling equipment rack.

Figure 3.3 Maximum E-field strength inside empty chamber and chamber loaded with 4 pieces of

66 cm rf absorber for 1 W net Input power determined from composite of 3 antennas

received power measurements. Data obtained using mode stirring approach.

Figure 4.1 Block diagram of NBS reverberation chamber evaluation and EMC measurement system.

Figure 4.2 Major software tasks for performing and evaluation susceptibility tests using a reverberation chamber.

Figure 4.3 Flow diagram for mode-tuned measurements.

Figure 4.4 Flow diagram for mode-stirred measurements.

Figure 5.1 Block diagram of NBS anechoic chamber EMC/EMI measurement system. Side view of

chamber. The outside width is 6.7 m.

Figure 5.2 Comparison of 1 cm dipole probe's peak responses to EM field established inside

NBS reverberation and anechoic chambers. Output normalized to E-field exposure

of 37 dB V/m.

29
Figure 5.3 Comparison of ridged horn's peak responses to EM field established inside NBS

reverberation and anechoic chambers. Output from horn normalized to exposure E- field of 37 dB V/m. a) Antenna output versus frequency, b) Difference in output

responses of ridged horn measured in NBS reverberation and anechoic chambers

compared to calibrated gain of horn.

Figure 5.M Photograph of 1 2 cm x 18 cm x 36 cm rectangular TEM cell with 5.1 cm x 5.1 cm aperture.

Figure 5.5 Comparison of power coupled to one port of 12 cm x 1 8 cm x 35 cm TEM cell with

5.1 cm x 5.1 cm aperture placed inside NBS reverberation and anechoic chambers.

Figure 5.6 Photograph of 1 2 cm x 1 2 cm x 24 cm rectangular TEM cell with 3-1 cm diameter

aperture.

Figure 5.7 Comparison of power coupled to one port of 12 cm x 12 cm x 24 cm TEM cell with

3.1 cm diameter aperture placed inside NBS reverberation and anechoic chambers.

Figure 5.8 Photograph of 3.0 cm x 5.0 cm x 11.4 cm rectangular TEM cell with 1.4 cm diameter

aperture.

Figure 5.9 Comparison of power coupled to one port of 3.0 cm x 6.0 cm x 11,4 cm TEM cell

with 1 . 4 cm diameter aperture placed inside NBS reverberation and anechoic

chambers

Figure 5.10 Photograph of modified 7.0 cm Folding Fin Aircraft Rocket inside NBS

reverberation chamber.

Figure 5.11 Photograph of modified 7.0 cm Folding Fin Aircraft Rocket inside NBS anechoic

chamber

Figure 5.12 Comparison of 7.0 cm modified FFAR thermocouple responses to EM field established

inside NBS reverberation and anechoic chambers. Data normalized to exposure

2 power density of 10 mW/cm . a) Thermocouple output vs frequency, b) Difference

in thermocouple output measured In NBS reverberation and anechoic chambers.

Figure 5.13 Examples of azimuth patterns of 7.0 cm modified FFAR thermocouple response taken

in NBS anechoic chamber.

Figure 5.14 Comparison of the average and maximum E-field strengths inside the NBS and NSWC

reverberation chambers determined for 1 W net input power using 1) reference

antenna received power measurements, and 2) calibrated 1 cm dipole probe

measurements, (a) NBS chamber, (b) NSWC half chamber, and (c) NSWC full chamber.

Figure 5.15 Comparison of 1 cm dipole probe's peak responses to normalized E-field of 37 dB

V/m using NBS and NSWC reverberation chambers.

Figure 5.15 Comparison of ridged horn's peak responses to normalized exposure E-field of 37

dB V/m using NBS and NSWC reverberation chambers.

Figure 5.17 Comparison of 7.0 cm modified FFAR thermocouple responses to EM field established

inside NBS and NSWC half reverberation chambers. Data normalized to exposure

2 power density of 10 mW/cm . a) Thermocouple output vs frequency, b) Difference

in thermocouple output measured in NBS and NSWC reverberation chambers.

Figure 5.1 E-field strength measured inside NBS reverberation chamber using array of 7 NBS

isotropic probes: (a) average, and (b) maximum. Comparison shown between

results obtained before and after normalization of measurements to correct for

changes in net input power. Normalized data corrected for net input power of 1.0

watt, chamber excitation antenna is log periodic. E is average field strength

determined from 7 probes.

30
Table 6.1 Summary and estimates of measurement uncertainties for determining field strength

inside NBS reverberation chamber - Mode Tuned (200 MHz - 2.0 GHz).

Table 6.2 Summary and estimates of measurement uncertainties for determining field strength

inside NBS reverberation chamber - Mode Stirred (2.0 GHz - 18.0 GHz).

Table 6.3 Estimates of impedance mismatch uncertainties for received power measurements.

Table 6.4 Estimates of uncertainties due to limiting number of tuner positions (sample

size)

.

31
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Dist inct

modes

Mode # Frequency

MHz Distinct

modes

33

Mode #

222

Frequency

MHz

1 110 59.13 161.16

2 Oil 63.83 34 320 161.49

3 101 73.59 35 240 164.05

4 111 80.58 36 013 167.48

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6 021 85.48 38 042 170.95

7 121 98.62 39 150 171.32

8 210 103.69 40 103 171.44

9 130 110.07 41 241 172.94

10 201 112.57 42 051 173.00

11 031 112.66 43 113 174.55

12 012 114.30 44 023 176.87

13 211 117.26 45 232 177.08

14 220 118.25 46 330 177.38

15 102 120.03 47 142 177.89

16 131 122.93 48 151 179.86

17 112 124.43 49 123 183.58

18 022 127.66 50 302 183.73

19 221 130.31 51 331 185.64 20 122 136.81 52 312 186.64

21 230 139.18 53 250 191.33

22 140 140.20 54 203 191.44

23 041 142.25 55 033 191,48

24 202 147.18 56 213 194.23

25 032 147.25 57 322 195.10 26 231 149.56 58 242 197.23

27 141 150.51 59 052 197.28

28 212 150.80 60 340 197.50

29 310 151.15 61 133 197.71

30 132 155.25 62 251 199.01

31 301 157.37 63 410 199.44

32 311 160.76 64 223 202.38

Figure 2.1 Distinct frequencies of modes in NBS 3.05 m wide

by 4.57 m long x 2.72 m high shielded chamber below

200 MHz.

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the 180 MHz to 200 MHz frequency band for the NBS chamber.

Figure 2.9

NIS chaaber (a - 2.74«

l^ b - 3.05TM

[ i • 4.57a

330 * f * 350 MHz (261 modes)

0.»S Cumulative distribution curve of the normalized 1/Q values in the 330 MHz to 350 MHz frequency band for the NBS chamber.

'a - 2.741II NBS chanber ( b - 3.05in

- 4.571

Figure 2.10 Cumulative distribution curve of the normalized 1/Q values in the 480 MHz to 500 MHz frequency band for the NBS chamber.

39
Figure 2.11 Photograph of interior of NBS reverberation chamber,

40
EMPTY CHAMBER LOSS, TRANSMIT TO RECEIVE flNTENM=lS

45

T I n 1 I I I I I I I 1I I I I I

se FREQUENCY (GMi)

Figure 2.12 Average and minimum losses between transmitted and received

powers measured at antennas' terminals inside NBS reverberation

chamber. Transmitting antennas are: log periodic (200 MHz - 1000 MHz), ridged horn (1.0 GHz - M.O GHz), double ridged

circular horn (M.O GHz - 18 GHz). Receiving antennas are: long

wire (200 MHz - 1000 MHz), ridged horn (1.0 GHz - l|.0 GHz),

double ridRed circular horn (>i.O GHz - 18 GHz).

41
u

9.E+5

7.E+5

CO 5.E+5

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].E+=

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cr

THEDRETICRL COMPOSITE Q and EXPERIMENTRL Q —I

1—I—I I I I I I r 1

\—r—r-r

(a)

45 -

35 -

25 -

15

FREQUENCY (GHz)

RRTIO OF THEORETICRL TO EXPERIMENTRL

~i 1—I—I—I I I I I r 1 1 VT'TT

(b)

..«w^

.2

J I L J I I I I I 2

FREQUENCY (GHz

J

Figure 2.13 Theoretical composite Q and experimental Q' determined for NBS

reverberation chamber, a) Theoretical and experimental values

of Q as a function of frequency. b) Ratio of the theoretical

composite Q to experimental Q' as a function of frequency.

42
Figure 2.14 Bulkhead panel used for accessing NBS reverberation chamber.

43
Figure 2.15a Photograph of field tuner/stirrer installed in McDonnell

Douglas Corporation 2.4 mx 3.0mx 7.6in TEMEC

(reverberation chamber) facility.

Figure 2.15b Photograph of field tuner/stirrer installed in NSWC

3. 5 m X 5. 2 m X 5. 9 m reverberation chamber.

44
Figure 2„15c Photograph of field tuner/stirrer installed in NBS

2.7mx3<.lmx4.6m reverberation chamber.

Figure 2.15. Tuner designs for use in reverberation chambers

a) McDonnell Douglas Corp. TEMEC tuner, b) NSWC

chamber tuner, c) NBS chamber tuner.

45
Figure 2.16 Photograph of tuner, log-periodic transmitting antenna and NBS

isotropic probes inside NBS reverberation chamber.

46
Finger Stock Material

^•^>^ wrapped around shaft

Chamber Wa I I Figure 2.17a. Details of collet for mounting tuner shaft to motor

through wall of reverberation chamber.

Figure 2.17b. Photograph of tuner shaft mounted through collet on ceiling of NBS reverberation chamber.

Figure 2.17 Details of tuner and stepping motor mounting for the NBS

reverberation chamber.

47
MAXIMUM TO MINIMUM RECEIVED POWER IN EMPTY CHRMBER

45 -

35

25

15

FREQUENCY (GHz)

MnXIMUM TO MINIMUM RECEIVED POWER WITH RBSORBER LORDING.

45 -

25

15 -

20

FREQUENCY (GHz)

Figure 2.18 Ratio of maximum to minimum received power obtained by rotating

tuner in the frequency range 200 MHz to 18 GHz. a) Empty

chamber, b) Four pieces of 66 cm rf absorber placed upright in

center of chamber, 0.5 m above floor.

48
TOP VIEW Bulkhead

3. Ota

[>!<]- -Tuner

3.74a

&<^Tuner

r-BBS Probes^

SIDE TICT IND TI«W

Cross sectional views of NBS reverberation chamber for use at frequencies

Figure 2.19a. g^ove 1.0 GHz showing location of antenna and NBS probes.

4.S7B

3. Ota

2.74a

P>'^J'«-Tuner

(-H.Oa

O

7 2i

Door L

8IDI Tin IND TIBV Figure 2.19b Cross sectional views of NBS reverberation chamber for use at frequencies

below 1.0 GHz showing location of antenna and array of NBS prdbes.

Figure 2.19 Cross sectional views of NBS reverberation chamber showing

placement of tuner, transmitting and receiving antennas, and

NBS probes.

49
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EMPTY CHAMBER LOSS, TRflNSMIT TO RECEIVE HNTEMIIRS

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HVERRGE LOS=

MINIHUn LOBE

J I \ I Mill I I I 1 I I I I 20

rPEOUENCY (GHz)

Figure 2.23 Average and minimum losses between transmitted and received

powers measured at antennas's terminals inside NBS

reverberation chamber. Long wire antenna transmitting (200 MKz

- 18 GHz), composite of three antenna receiving (log periodic

200 MHz - 1000 MHz, ridged horn, 1,0 GHz - i|.0 GHz, double

ridged circular horn, H.O GHz - 18 GHz).

CHAMBER LOSS WITH flBSORBEP, TPRN3 T8 REG RNTENNRS

se

40

38 -

se -

10

"I—I I I I I I

NIMUM LOSS

J I

I I I I I J l_L

20

FREQUENCY (GHz)

Figure 2.2iJ Average and minimum losses between transmitted and received

powers measured at antennas' terminals inside NBS chamber with

four pieces of 66 cm rf absorber upright in center of chamber,

0.5 m above floor. Composite of three antennas used for

transmitting and receiving.

53
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Frequency (MHz)

Figure 2.25 Magnitude of wave impedance inside NBS reverberation chamber.

E-riCLD IN CMPTY CHflMBCR (MODE TUtCD), I WATT INPUT

O

_J u

M

u.

I Ui

FREQUENCY (GHz)

Figure 2.26 Average and maximum E-field strengths inside empty NBS reverberation chamber for 1 W net input power determined from:

a) composite of 3 antennas received power measurements, and b) calibrated 1 cm dipole probe measurements.

54
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56
Ave: of :xrz ^ total rve e-field mersured with i ppoees

45 T T \—I I I

TC'TfiL E-FIELD **+*

*******W«?,V*-

TRRNS COMP (X) ****

VERT COMF I V ) 4+++

LONG COMP (2) XXXX

(a)

. 1 J I 1 I I I FREQUENCY (GHz

RVE OF >:\Z &- TOTAL MAX E-FIELD MEASURED WITH 7 PPOEES

T \ r

TOTAL E-FIELD ++++

(b)

"1 1

\—TT

TRfiNS COMP (X) »*•

VERT COMP (Y) ++++

LONG COMP (Z) XXXX

J L J L FREQUENCY (GHz)

Figure 2.28 Mean values of the E-field strength measured inside NBS

reverberation chamber using array of 7 NBS isotropic probes

with 1 W net input power: (a) average, and (b) maximum. Data

determined from maximum and average values of the 7 probes (7

locations) for the three orthogonal components and their sum

(total) using 200 tuner positions (1.8 degree increments).

57
Figure 3.1a Photograph showing 30 cm x 50 cm x 60 cm welded aluminum

box inside NBS reverberation chamber.

58
^ J(^

Figure 3.1b

Figure 3.1

Photograph showing rolling equipment rack inside NBS

reverberation chamber

„

Placement of metallic objects inside NBS reverberation

chamber to evaluate scattering effects upon E-field spatial

distribution. a) Photograph showing 30 cm x 50 cm x 60 cm welded aluminum box inside NBS reverberation chamber. b)

Photograph showing rolling equipment rack inside NBS

reverberation chamber.

59
^0 E-rrCLD MRX ^nd HVG V'HLLCS i n EMFTr 'THRU,

38

32

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4=flLUM. BOX flVG (a)

J I I I I 1 I I I . I I

I

. I 100 29a 480 670 360 105D 1240 1433 1620 1818 2900

FREQUENCY CMHiJ

190 29a 489 879 960 1B50 1249 1433 1629 1810 2000 FREQUENCY CHHl)

Figure 3-2 Comparison of the mean value of the average and maximum E-field

strength measured using array of probes placed inside

NBS reverberation chamber with chamber empty or with scattering

object placed at center of test zone, a) 30 cm x 50 cm x 60 cm aluminum box, b) Rolling equipment rack.

60
MflXIMUM E-riELD FOR 1 NHTT INPUT W/NO RB50RBER

45

1 1 1 1 1 1 III 1 1 1 1 1 1

EHPTY CHRMBER

rr

35

X

^

^^^^^^^^V^^v^j

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- \

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15

:

5

1 1 1 1 1 1 III 1 1 1 1 1 1 1 1 .2 se rREOUENCY (GHz)

Figure 3-3 Maximum E-field strength inside empty chamber and chamber

loaded with 4 pieces of 66 cm rf absorber for 1 W net input

power determined from composite of 3 antennas received power

measurements. Data obtained using mode stirring approach.

61
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62
miBBUiREmmB

mOE YUME

SHE^SUIMEMmS

mriR LEBIMIBl^Y

i I

Figure H .2 Major software tasks for performing and evaluation

susceptibility tests using a reverberation chamber.

63
nODE TUNE

tlERSUREMENT

CRLIBRRTE

METERS

SELECT PRRRMETER

VRLUES

INITIRLIZE SYSTEM

RF POWER OFF

ZERO MEIERS and

REFSD ZERO OFFSETS

SET FREQUENCY

HPPLY RF PO»ER

REDUCE POWER

RERD

INSTRUMENTS

NEXT FREQUENCY

GROUP DRTR by

FREQUENCY

PERFORM SIMPLE

STATISTICS

APPLY SYSTEM

CRLJBRRTIONS and ZERO OFFSET VRLUES

CRLCULRTE BRSIC 0URNTIT2ES

STORE RESULTS on MRSS STORRGE

LRST STEP o7 YES STORE DRTR on ,,^C FULLJ,,^ MFSS STORRGE

NO

GRRPH DRTR

END

Figure 4.3 Flow diagram for mode-tuned measurements.

64
nODE STIR

nERSUREnENT

CRLJBRRTE

METERS

SELECT PFRRMETER

VRLUES

INITJRLJZE

SYSTEM

RT POHER OTF ZERO MCTD?S and RERD ZERO OFFSETS

SET FREOUENCr

RESTPRT CONDITION

ERROR DETECTED

FIND POUER LEVEL to PRODUCE MINIMUM CUT

RESPONSE

SET POUER LEVEL to EXISTING VRLUE

RERD NET POUER IN START TUNC/? MOTION

TRIGGER INSTRUMENTS

SET ERROR FLAG

REDUCE POUER

SET ERROR FLRC RDJUST and RESET MO TO?

RDJUST PRRP^ETERS

RERD

INSTRUMENTS

flPPLr SYSTEM

CRLIBRRTIONS and ZERO OFFSET VRLUES

CRLCULRTC and TRBULRTE RESULTS

RF PONER OFF MCRSUREMENT

COI^LETE ANEXT FREQUENCY}-

Figure h .>^ Flow diagram for mode-stirred measurements.

65
c t—

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ononR'PlV'PPR

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35

25

CHAMBER

1 1 1 1 1 1 1 1 1 11 1 1 1 .2

FREQUENCY (GHz)

Figure 5.2 Comparison of 1 cm dipole probe's peak responses to EM field

established inside NBS reverberation and anechoic chambers.

Output normalized to E-field exposure of 37 dB V/m.

67
35

PCflK HOPN RESPONSE far ftfCCHOIC »nd REVEPB CHAMBERS

3e

25

20

15

IS

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DirrEPENCE .n RERf HOP^/ RESROMSE -for RNECHOIC ind PE'/ERB CHRMBERS

CO

208 2Beo

FREQUENCr (MHz

secdo

Figure 5.3 Comparison of ridged horn's peak responses to EM field

established inside NBS reverberation and anechoic chambers.

Output from horn normalized to exposure E-f ield of 37 dB V/m.

a) Antenna output versus frequency, b) Difference in output

responses of ridged horn measured in NBS reverberation and

anechoic chambers compared to calibrated gain of horn.

68
Figure 5.^ Photograph of 1 2 cm x 18 cm x 36 cm rectangular TEM cell with

5.1 cm X 5.1 cm aperture.

-30

-3^

IgvlBcm TEM CELL; gIMGLE ENDED

-bb

-7ri

-1

i <- 1

' T

Anechoic Chamber

Peak Response everb Peak

Reverb Average

Peak Exposure E-field is 37 dB V/m

188 £GQ 308 468 588 688 ?BD 888 9QQ 1888 1188

FREQUENCY f MHz J

Figure 5.5 Comparison of power coupled to one port of 1 2 cm x 1 8 cm x 36 cm TEM cell with 5.1 cm x 5.1 cm aperture placed inside NBS

reverberation and anechoic chambers.

69
Figure 5.6 Photograph of 1 2 cm x 12 cm x 24 cm rectangular TEM cell with

3.1 cm diameter aperture.

a:u

-^Q

-•A A

-A3

13. 13 cm TEM CELL, SINGLE ENOED

-5;

-56

-60

-6^

-68

-30

++++ M

irlTTi: M

Hxiriun

v'ERMGE

Theoretical Peak

Anechoic Chamber

Peak Response

Figure 5.7 Comparison of power coupled to one port of 1 2 cm x 12 cm x 21 cm TEM cell with 3.1 cm diameter aperture placed inside NBS reverberation and anechoic chambers.

70
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^neqhoic

Theoretical

Peak

Peak E-field = 37 dB V/ra

lee 500 998 1309 1799 2 1BD 2599 2900

FREQUENCY C MHz

3399 3799 4 199

Figure 5.9 Comparison of power coupled to one port of 3,0 cm x 6.0 cm x 11. iJ cm TEM cell with 1.4 cm diameter aperture placed inside

NBS reverberation and anechoic chambers.

72
oo

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73
Figure 5.11 Photograph of modified 7.0 em Folding Fin Aircraft Rocket

inside NBS anechoic chamber.

74
FFRP PERi: irJ fllJECHOIC MND REVERB. CHRtlBERS

90

70

59

3C-1 -

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16

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J I I I I I 1B000

Figure 5-12 Comparison of 7.0 cm modified FFAR thermocouple responses to EM field established inside NBS reverberation and anechoic

chambers. Data normalized to exposure power density of 10

2 mW/cm . a) Thermocouple output vs frequency, b) Difference in

thermocouple output measured in NBS reverberation and anechoic

chambers.

75
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PEHK RESPONSE of 1cm DIPOLE in VRRIOUS CHRMBERS

80

+ + + +

1 1 1 1 1 1 1

NBS Reverb

1 1 1 1 1 1 1 1

^kj

OO OO

NSWC Half Reverb

N5WC Fu 1 1 Reverb

TM"

G0 - Min

50 - Al K]\J\jM^f l._

40 - ^p^ -

30 - -

20 1 1 1 1 1 1 1 1 1 1 1 1 1 t 1 1 20

FREQUENCY CGHz)

Figure 5.15 Comparison of 1 cm dipole probe's peak response to normalized

E-field of 37 dB V/m using NBS and NSWC reverberation chambers.

PERK RESPONSE of RIDGED HORN in VRRIOUS CHRMBERS

30 1 1 1 1 ! ! 1 1 1 1 1 1 1 1 1 1

25 - -

20 - V. -

15 - ^Ik -

10 - ^%k -

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FREQUENCY (GHz)

Figure 5.16 Comparison of ridged horn's peak responses to normalized

exposure E-field of 37 dB V/m using NBS and NSWC reverberation

chambers.

78
NB5 REVERE. DRTH vs NSH C REVERB. DHTR I MODE-^.T IPPED

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25

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I 1B00

FREQUENCr itlHz ) 10000

DIFFERENCE in FFRR PEAK RESPONSE -for NBS »nd NSWC REVERB CHAMBERS

100 1000

FREQUENCY (MHz)

10000

Figure 5.17 Comparison of 7.0 cm modified FFAR thermocouple responses to EM field established inside NBS and NSWC half reverberation

chambers. Data normalized to exposure power density of 10

2 mW/cm . a) Thermocouple output vs frequency, b) Difference in

thermocouple output measured in NBS and NSWC reverberation

chambers.

79
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81
Table 6.1 Summary and estimates of measurement uncertainties for

determining field strength inside NBS reverberation chamber - Mode Tuned (200 MHz - 2.0 GHz)

Source of Error

1

)

Measuring Received Power

Cable Loss Attenuator Calibration

Antenna Efficiency

Power Meter Calibration

Total

2) Receiving Power Mismatch

(See Figure 6.1

)

3) Mixing/Sampling Efficiency

Spatial Field Uniformity

(see figure 2.27)

Limited Sample Size

(see Table 6.1)

Total

Error (dB)

200 MHz 500 MHz 1 .0 GHz 2.0 GHz Ave. Max. Ave. Max. Ave. Max. Ave. Max

+ 0..05 ±0.05 ± 0,.05 ± 0.,10

± 0,.10 ± 0.10 ± 0,.10 ± 0,.10

± 0,.05 ± 0.05 ± 0,.05 ± 0,.10

± 0,.20 ±0.20 ± 0..20 ± 0,.20

± 0.40 ± O.ilO O.lJO ±0.50

-2. -5.1 -1 .5 -S.'* -0.7 -1 .5 -0.3 -0.7

± 8.0 + 5.0 + 3.0 ± 2.0

±0.2 ±0.5 ±0.2 ±0.5 ±0.2 ±1.5 ±0.3 ±1.0

±8.2 ±8.5 ±5.2 ±5.5 ±3.2 ±4.5 ±2.3 ±3.0

4) Wave Impedance * 120Tr -2.8 -2.8 -2.0 -2.0 -2.0 -2.0 -2.0 -2.0

(see Figure 2.25) +2.0 +6.0 +2.0 +6.0 +2.0 +4.5 +2.0 +3-0

Total Worst Case Error

-14.2 -16.8

+10.6 +14.9

-9.1

+7.6

-11.3

+ 11 .9 -6.3 -8.4

+5.6 +9.4

-5.1 -6.2

1-4.8 +6.5

RSS Error

-9.1 -10.3 -5.8 -6.8

+8.5 +10.4 +5.6 +8.1 -3.9 -5.2+3.8 +6.4

-3.1 -3.7

+3.1 +4.3

I Failure to Correct for

Input Power Variations

(Transmit Mismatch Error]

-4.0 -3.0 -2.0 -1 .0

82
Error (dB)

2.0 GHz 4.0 GHz 8.0 GHz 12.0 GHz 18.0 GHz

Ave. Max. Ave. Max. Ave. Max. Ave. Max. Ave. Max.

± 0,.10 ± 0,.10 ± 0..15 + 0.15 ±0.20

± 0,,10 ± 0,.15 ± 0..15 ±0.20 ±0.20

± 0,,10 ± 0,.15 ± 0,.15 ± 0.20 ±0.20

± 1 .,50 ± 1 ..50 + 1 ..50 ± 1.50 ± 1 .50

Table 6.2 Summary and estimates of measurement uncertainties for

determining field strength inside NBS reverberation chamber - Mode Stirred (2.0 GHz - l8.0 GHz)

Source of Error

1 ) Measuring Received

Power

Cable Loss Attenuator Calibration

Antenna Efficiency

Spectrum Analyzer Cal.

Sub Total ±1.80 ± 1.90 ±1.95 ± 2.05 ± 2.10

2)Receiving Power

Mismatch

(see Figure 6.1) -0.8 -0.8 -0.8 -1.0 -1.8

3) Mixing/Sampling

Efficiency

Spatial Field Var. ±2.0 ±1.0 ± 0.5 ± 0.2 ± 0.2

Limited Sample Size

(see Table 6.4) ±0.1 ±0.3 ±0.2 ±0.5 ±0.3 ±0.7 ±0.3 ±1.0 ±0.3 ±1.5

Sub Total ±2.1 ±2.3 ±1.2 ±1.5 ±0.8 ±1.5 ±0.5 +1.2 ±0.5±1.7

4) Wave Imped * 120Tr Average i ±2.0, -2.0 i Maximum ^ +3.0

5) Failure to Correct

for Input Power Var. -0.8 -0.8 -0.8 -1.0 -1 .i

TotaKWorst Case)Error -7.5 -7.7 -6.7 -7.0 -6.4 -6.8 -6.6 -7.3 -8.2 -9.4

+5.9 +7.1 +5.1 +6.4 +4.8 +6.2 +4.6 +6.3 +4.6 +6.8

RSS Error -3.6 -3.7 -3.1 -3.3 -3.1 -3.2 -3.2 -3.4 -3.9 -4.2

+3.4 +4.2 +3.0 +3.9 +2.9 +3.8 +2.9 +3.8 +2.9 +4.0

83
Table 6.3 Estimates of impedance mismatch uncertainties for received power

measurements

VSWR Mismatch Error

Frequency Source Load (dB)

GHz Ave Max Max Ave Max

0.2 5.0 10.0 1 .10 -2.83 -5.15

0.5 3.0 6.0 1 .10 -1 .il6 -3.i<0

1 .0 2.0 3.0 1 .10 -0.66 -1 .16

2.0 1.5 2.0 1 .10 -0.27 -0.66

2.0 2.0 2.0 1 .20 -0.81 -0.81

4.0 2.0 2.0 1 .20 -0.81 -0.81

8.0 2.0 2.0 1 .20 -0.81 -0.81

12.0 2.0 2.0 1 .30 -0.95 -0.95

18.0 2.5 2.5 1.50 -1 .77 -1 .77

Table 6.4 Estimates of uncertainties due to limiting number of tuner

positions (sample size).

Error due to limiting Sample Size

Ave/Max (dB)

Frequency Number of Tuner Posi tions

GHz 50 100 200 400 800

0.2 0.2/0.8 0.2/0.5 — — —

0.5 0,6/3.6 0.5/2.0 0.2/0.5 — —

1 .0 — 1 .0/4.0 0.2/1 .5 0.2/0.5 0.1/0.2

2.0 — ~ 0.5/3.0 0.3/1.0 0.1/0.5

4.0 ~ — — 0.5/3.0 0.2/1 ,0

8.0 — — — — 0.5/3.0

84
APPENDIX

Computer Programs for

Reverberation Chamber Immunity Measurements

85
1 o<:) I 102

104

106

108

1 10

112

114

116

lis

120

122

124

126

128

130

132

134

136

138

140

142

144

146

148

150

152

154

156

158

160

162

164

166

lr68 170

172

174

176

178

ISO

182

184

186

1 88

190

192

194

196

193

2(1'0 202

204

206

208

2 1 212

214

216

KE-STOF';E "ModeTuneOl " Oriqinal: 5 May 1984 G. Koepke

Revision: 21 Feb 1936, 09:20

(303) 497-5766

ThiE measurement routine will operate the R'EVER'BEFxAT ION CHAMDER

using MODE TUNED techniques. The tuner is stepped in discrete:- steps

and measurements Are performed at each step. In this version ALL

•frequencies are measured at each tuner step be-fore proceeding

to the neKt step. Both the case o-f susceptabi 1 i ty (power suppiie^-d

by a signal generator) and emissions (power supplied by EUD can be

handled. This program will handle EUT emissions by not measuring

the net input power and recording the received power as detected

by the reference antenna. Duplicate measurements are required to

inject an 'equivalent' (will be normalized later) power to set

up the same response using the transmit antenna as was measured

with the EUT only. This method will determine the tote^l power

radiated by the EUT.

The prograni will also handle the case where the tuner is not stepped,

as in a TEM cell or ANECHOIC chamber where a single measurement

is needed. The data is condensed for this case. Coupler, cable loss, and Power meter head corrections are applied

immediately to the measured data. These computations (nust be verified

by examining program lines that begin with the line label

Appl y_cal _,data , merely e;;ecute the? EDIT command as shown.

EDIT Apply_cal_data

The measuremerit data are saved on disk: for processing. It may also

be tabulated as the measurement proceeds by toggling a print flag

that is shown at the start of each tuner step.

Features: 1) NB3 multi probe system

2) HF' 436 and/or HP 438 power meters

3) HP 3456 or 3478 DVMs

4) HP 8566 Spectrum Analyzer (Power only)

5) HP relay actuator for RF switching

6) Superior Electric Stepping motor control

7) Either of HP8660A or HP3672A signal source. Current Configuration

F'erform preliminary emissions e;;perimerits in the chamber.

Standard items: 1) Incident F'ower to trar-ismit antenna

2) Reflected power from transmit anter^na

3> Received power from reference antenna

Me?ssure output o(:

Special Notes

Any number of NBS probes via system,

[not used for emission tests]

86
218

220

224

226

228

230

234

236

233

240

242

244

246

24G

250

252

254

256

258

260

262

264

266

268

270

272

274

276

278

230

282

234

286

283

290

292

294

296

298

300

302

304

306

308

310

314

316

318

320

324

326

328

*«»* x *)(****»(** -x * * MAIN F R: LJ G R AM * * * * * * )* f^- x- * * «- * * K-ith***)' k }( x- * * * * OPTION base: 1 DEG

OUTPUT 2 USIfJO "f;;,tt"; CALL Wipe_ clean

GOSUD Di m _ var i ab 1 es GOSUB Load_cal__data

New_measurement : I PRINTER IS CRT

DISP CHR*(129)

G03UB Ini tial_values

GOSUD S i g _g en _s u b s

'SCRATCH KEYX"

! Dimension all variables, set selec

! Load all calibration data foi" pads

ted val Lit-?;

?.: cables.

GOSUB

GDSUB

GOSUB

Fi 1 leal ibration

Do_measu.rements

Di e__ graceful 1 y PRINTER IS CRT

DISF :TIME*(TIMEDATE)

DISP " PAUSE

GOTO N STOP

F'reset all parameters and a Load selected Signal Genef"a

and selected coupler calibr

Fill lookup table for calib

< — read it again

Delete signal gen erator sub

"

; DATE:f ( T 1 MEDATE > ; " .... PR

cc ess m tor sub

a ton da

rati on

B from

OGRAM F

ta. val ues. memory

INI SHED,

'CONTINUE' to repeat."

w measurement

•X-**** »( *************- END cT MAIN FT\'OGRAM ************ * -x ** ***

/ / / / / / / / / / / / / / / / / *** D I ME:NS 1 ON VAF; I ABLES ***//// / / / / / / / / / / / /

Di m_var i ab 1 es : !

I COM /Parameters/ REAL Fstart , Fstop , Fstep

COM /Parameters/ F:£AL Mi n_eut , Max _eut , Mi n_pwr , Ma;; _pwr , Time_eut

COM /Parameters/ INTEGEFi Low dbm,High_dbm,Step_dbm

COM /Parameters/ INTEGER Seiirch_eut , Search_jDwr ,Re_run

COM /Parameters/ INTEGER Begi n_step , Total _3teps , Total _meters

COM /Parameters/ Run._id*C lOJ , Measmt_i dfC 160D , Ti me_date*C30]

COM /Parameters/ Meter_def nst- (40) [40^ , Operator_namet [ 283 , Test_,typetC20:

COM /Parameters/ Coupl er_ i d*[ 103 , Generator_i d*: 101

I COM /Probe_system/ INTEGER Sys_si ze , Total _chans , Probe._addr (30 , 3)

COM /Probesystem/ INTEGER Top_.probe , Fcal __pts ,F'r_avgs

COM /Probe .system/ INTEGER Pr obe _vol ts (30) , Overrange (30)

COM /Probe_system/ INTEGER Probe._zero ( 30) , REAL Probe._v_m (30)

COM /Probe system/ REAL Amplitude cal (11,3,5) ,Freq._cal (11,3,13,2)

COM /F'robe_system/ REAL Readt i me (30) , Freq._cr i b ( 13 , 2)

I COM /Interrupts/ INTEGER Intr_j.-.rty

COM /Motor_meni.i./ Mot i on type*r. 1 J , Rev_ rate , INTEGER Tuner _steps

COM /Bugs/ INTEGER Bug 1 , Bug2 , Bug3 , Pr i nter

COM /Fi ies/ Sourced i sk*C201 , Outd i sk:^ L 201 ,Fi lename^CSO]

Cable and etc- calibration -files.

DIM Baddata id*(15)[40:

INTEGER Calib. .items

I DIM Coup_ i nc (205 , 2) ,Coup_re-fl (205,2)

INTEGER Inc_pts,Re-f l_.pts

87
-.8 340

>42

344

346

343

350

352

554

?56

558

560

562

564

::66 568

570

572

37 4 376

573

380

382

3S4

386

533

390

592

394

^•6 393

400

402

404

406

408

410

412

414

416

413

420

422

424

426

42S

430

432

434

436

433

44

442

44 4 446

44B

450

452

454

456

REAI L'cupi nc , Ccupr e-f 1

DIM Cable6._i (130,2) , Cabl e6_6 ( 130 , 2) ,Cable4_2( 130,2) ,Cable4_4 '130,2)

INTEGER C6_lpts,C6__6pt,s,C4__2pt3,C4_4pts

REAL Ct._no=.5,C6_61o£S,C4_21o55,C4 _41o55

1 D I M Cab 1 e- 1 _ 3 ( 1 80 , 2 ) , Cab 1 e 1 0__5 ( 1 80 , 2 ) , Cab 1 e5._7 ( 1 SO , 2

)

I NT EGER C 1 0_3p t s , C 1 0_5p ts , C5_7pts

REAL C 1 0_31 c 55 , C 1 0_.51 oss , C5_7 1 oss

I DIM Cable_r4 (80,2) ,Cable^.rl2 (80,2)

INTEGER Cr4pt3,Crl2pts

REAL Cr41o5S,Crl21 oss

I DIM Pad. as6a (180,2) , Pad..s6770 ( ISO , 2) , Rad_f 5530 ( 180 , 2)

INTEGER R3.dc....pt3,Rad5_.p'ts ,Radf _pts

REAL Pada _I055 ,F'ads_loss , Padt _los5

I DIM hi .ict (77,2) 'Anrac Hybrid Junction

INTEGER Jct_pts

REAL Jet loss

! Other useful variables.

DIM Cal_id*i:403 , Pwr_.i d*i;2D ,Te5t*[ 160:

INTEGER E-iaddata,Dbm,R-f_on_o-f-f , Fi 1 esi ze , I , J ,K,P

INTEGER Valid, Ftotal , Fi 1 e20stBp5 , Begi nstep , Endstep

INTEGER Pri ntf I ag , Fcount , Too_hot , Pr i ntf 1 ag2 , Steps

INTEGER Local _prty, Probe

IINTEGER Pp436al , Fp436a2 , Fp438al , Fp438a2 , Fsae566b

INTEGER Fv3456al , Fv3456a2 , Fv3478al ,Fr59306a

REAL Z3456al , Z3456a2 , Z3473al

REAL V3456al ,V3456a2,V3473al

we need these initial values

or ": HP9 133, 700,0"

FTi nter = 701

Sourcedi5k.J:=": INTERNAL , 4 , 0"

Outdi5k:t=": INTERNAL, 4, 1" Intr_jDrty=6

Local _prty~lntr _prty

Bugs:

Ft 1 nt-f 1 aq=l I Print all setup parameters and calibration values.

Print+laq2=l ! Print raw data if both Printflag and PrintflaqZ

Buql-0

Bug 2=0

Bug 3=0

I RETURN

r

' ////////////////****INniALlZE VARIABLES ?•: I /Q****/ /////////// /

Ini ti al ^al ues: ! ASSIGN rsMotor TO 706

ASSIGrj (sPwrl TO 709

ASSIGN (5Rwr2 TO 710

ASSIGN ODual_p.wri TO 711

ASSIGN @Dual_pwr2 TO 712

Stepping motor

F'oi-jsr meters HF'436a

F'ower meters HP43&a
458

460

462

46 4

466

468

470

472

474

476

478

480

482

484

436

488

490

492

494

496

493

dOO

502

504

506

508

510

512

514

516

518

520

524

526

528

530

532

534

536

538

540

542

544

546

543

550

552

554

556

553

560

562

564

566

568

570

5^2

574

5 76

ASSIGrj (i:Siq_C5en 10 719

ASSIfJtJ wE;vinl AGSIErj 'l!Dvn,2 AS3IGM (aDvm3

ASSlGrj (ar-,pio

ASSIGM @R1 yl

ASSIGN eSpec

TO 722

TO 723

TO 724

TO 12

TO 717

al: r TO 18

Cal 1 b_i tems-lS

Ft _ ,avqs=3

Mot i on _t ype*= "STEP

'

Rev_ rate=l . Rf on of-f = l CALL lieasur

GOSUB Con-fi

CALL Multip

DISP CHRf'l

GOSUB D5ta_

GOSUB DiG__g

Dbin=Low_dbm

Tuner_step3

e_menLi

qure_instr

robe__frienu

29)

de-f ini ti on racef ul 1

y

^Total _5tep;

Signal generator HF'3&6r o. or HF'86/:

HP3456A Dvm,

HP3456A Dvm.

HP3473A Dvm.

NES Multi probe system

HP' relay actuator

HP 8566 Spectrum Analvzer

15 +ileB -for cables, coupler, and pad cals,

Read Multiprobe 3 times and average,

or "CONTINUOUS" -for MODE STIRRING,

used only ii MODE STIRRING operation.

I Go and set up rrieasureiiient parameters,

! Turn on /off instruments as per mer.u

! Set up the 30 probe system.

! Use above info to define data.

! To assure clean start.

! Initialize the Generator Level

! Initialise the motor control

Ftotal=INT(

IF Test._typ

Fi le205

ELSE

Fi le205

END IF ALLOCATE Ra

ALLOCATE THE RAW DATA MATRIX

(Fstop-Fstart) /f^step) +1

et="OTHER (NO STEPS)" THEN

teps=Ftotal

teps=20*Ftotal

wdata (Total _meter5+Total _chans+l , Fi 1 e20step = )

DISP "INSERT OUTPUl DATA DISK IN "; SELECT Outdisk:^

CASE ": INTERNAL, 4,0"

DISP "RIGHT DRIVE, "; CASE ": INTERNAL, 4, 1" DISP "LEFT DRIVE, "; END SELECT

DISP "and hit ' Conti nue-k5 ' .

BEEP

ON KEY 5 LABEL "Conti nue" , Local _prty GOTO Datasaver

Zippity:GOTO 7.ippity

DatasaveriOFF |:;;EY

GOSUB 3ave_conf igure

IF Pr inter OCRT THEN

PRINTER IS Printer

PRINT RPT*("_",80)

PRINT

PRINTER IS CRT

END IF G05UH Print_vital5

DISP CHRfa2)

RET URN

////////////////////////////////////////////////////////////

Conf iqure_ i rrstr : I

89
5/8

580

582

584

586

583

590

592

594

596

598

600

602

604

606

603

610

612

614

616

618

620

622

624

626

628

630

632

634

636

633

640

642

644

646

643

650

652

654

656

653

660

662

664

666

668

670

672

674

676

673

680

632

684

636

683

690

692

694

696

IriEtr ument read -flags, i -f Stepfjinq motor controlled by

Signal generator HPS660a or

NEiS Mi.ilti probe system control

SELECT T est _ type*

CASE "MUDE TUNE REijULAR"

Fp436al=0

Fp436a2=0

Fp43Sal=l

Fp 438*2=0

Fv3456al=0

Fs'3456a2=0

Fv3478al=0

Fr59306a=0

Fsa8566b=l

CASE "MODE TUNE EMISSIONS"

Fp 436 a 1=0

Fp436a2=0

Fp438al=0

Fp 438a 2=0

Fv3456al=0

Fv3456a2=0

Fv3478al=0

Fr59306a=0

Fsa8566b=l

CASE "OTHER (NO STEPS)"

Fp 4365 1=0

Fp436a2=0

Fp438al=l

Fp433a2=0

Fv3456al=l

Fv3456a2=0

Fv3478al=0

Fr59306a=0

F5a8566b=0

SELECT

set the meter wi 1 1 be read . .

Test._type*

HPSfc72a controlled by Test_typet

led by Total chans

Pc^^'er meter HP436a at add>- 09

F'ower meter HP436a at addr 10

F'ower meter Hr'43Sa at addr 1 j Power meter HP433a at addr 12

HP3456A Dvm at addr 22

HP3456A Dvm at addr 23

HP3478A Dvm at addr 24

HP relay actuator at addr 17

HP 8566 Spectrum Analyzer at addr 18

F'cwer meter HP436a at addr 09

Power meter HP436a a.t addr 10

Power meter Hr'438a at addr 1

Power meter HP438a at addr 12

HP3456A Dvm at addr 22

HP3456A Dvm at addr 23

HP3478A Dvm at addr 24

HP relay actuator at addr 17

HP 8566 Spectrum Analyzer at addr 18

Power meter HP436a at addr 09

F'ower meter HP436a at addr 10

F'ower meter HP433a at addr 11 F'ower meter HF'433a at addr 12

HP3456A Dvm at addr 22

HP3456A Dvm at addr 23

HP347BA Dvm at addr 24

HP relay actijator at addr 17

HP 85fc6 Spectrum Analyzer at addr 18

END

RETURN

/////////////////// /****DAT A DEF I N I T I ON****/ ////////////////

Data deFinition: Set up the definitions o-f each meter reading,

these are used later when processing

SO be sure these &rB correct.

The index corresponds to the Rawdata matrix rowH-1

Frequency is always in row 1 Meter 1 is in row 2, etc.

SELECT Test._type*

CASE "MODE TUNE REGULAR"

Total ._meter-s = 3

Metei' _de-f ns* ( 1 ) =" I nc i dent Power ^W

Meter def ns* (2) ="Ref 1 ected F'ower ',

Meter_de-f ns4 (3) ="F\'eci eved F'ower (W

CASE "MOOE TUNE EMISSIONS"

Total _meters=l

Meter defns* ( 1 ) ="Reci eved F'ower (W

CASE "OTHER (NO STEPS)"

Total _meter3=3

Meter de-f ns* ( 1 ) =" I nc i dent F'ower (Watts)

cT.tts; tts)

atts)

latts)

90
693 Mete?r def ns* (2) ="Re f 1 ected Power (Watts) " 700 MGter_.dG-f ns* (3)="Probe' Output (Volts)"

702 END SELECT

704 1 706 FriR P=l TO Total _chan5

708 Te5t*="A,Tip # "^-VAL* (Probe .addr (P , 1) )?<" , 5cm Probe #

" 710 Test-f=Testr?..Vh"-.L$ (Probe .addr (P,2) )?.:"-"

712 SELECT Probe addr(P,3)

714 CASE 1 716 le£;tt-Test*?'."X"

718 CASE 2

720 Testf = Te5t*?.'-"Y" 722 CASE 3

724 Test*=Te5tJ:?'."Z"

726 CASE 4 728 Te5t* = Test*?.:"Single"

730 CASE ELSE

732 Te5tf=Test*?'."Error I " 734 END SELECT

736 IF LEN(Test*) ;40 THEN

738 BEEP

740 DISP "ERROR in probe de-f i ni t i one " 742 PAUSE

744 Test*=Te5t*[l ,403

746 ELSE

748 Meter _de-fns4- (P+Total _meter5) =Te5t*

750 END IF 752 NEXT P 754 RETURN

756 ! 758 !///////////////////////// / /****D I E GRACEFULLY**** ////////////////

760 ! 762 Die_grace-f Lil 1 y: ! 764 IF Bugl THEM

766 PRINT TINE* (TIMEDATE)

763 PRINT RPT$(" : " , 15) ; " DIE GRACEFULLY " ; RPT* ( " >" , 15)

770 END IF 772 Ot^ ERROR GOTO Dc-let_donel

774 SELECT Gener ator_i d*

776 CASE "HP__8660A"

778 DELSUB Set _-f r eq , Set _db(Ti , FNDi g i 1 1 0* , FNDi g i 1 3* , FNRev*

730 CASE "HP_8672A"

782 DELSUB Set _-Fr eg , Set _dbm

784 END SELECT

786 Delet_donel: I 783 OFF ERROR

790 ON ERROR SOTO Delet_done2

792 DEALLOCATE Rawdata (*), Adjust (*)

794 Delet__dor,e2: ! 796 OFF ERROR

793 RETURN

300 I 802 ' /////////////////////// ////.W //////////////////////// ///////

804 • 806 Sig_gen subs: ! 808 PRINTER IS CRT

810 PRINT TABXY (1 , 18) ;RPTt ( "*" , 15)

812 PRINT " LOAD SUB PROGRAMS ?< Coupler Calibrations " ; RPT* ( "*" , 15)

814 Fi 1 ename*=Generator_i d-f ?<Sourcedi skf

816 DISP " Put 'CALIBRATION DATA ?< SUB Program' disk in ";

91
BIB

820

822

824

826

823

830

832

834

336

838

840

842

844

B46

848

850

852

854

856

858

860

862

864

866

863

870

372

874

876

878

830

882

884

886

833

890

892

894

896

893

900

902

904

906

903

910

912

914

9 1 6

918

920

922

924

926

928

930

932

934

936

SELECT SourcBdish*

CASE " : .LNTERNf^-L,4.0"

DIS=^' "RlBl-lT DRl'.'E, "; CASE ": IMTERNAL.4, 1" DISP "LEFT DRIVE. "; END SELECT

DISP "hit ' Cc.nt.inue-t-5 . " BEEP

ON KEY 5 LaE-:EL " Cont i nu.e" , Local _prty GOTO Subloacls

LOOP

END LOOP

SubloLdszOFF KEY

DISP CHR*(12)

DISP " Signal Generator SUB PROGRAMS NOW LOADING " ON ERROR CALL Err or trap

LOADSLIB ALL FROM Filename*

OFF ERROR

DISP " Signal Generator SUB PROGRAMS LOADED " WAIT 1

IF P IF P SELE

CASE

CASE

CASE

CASE

END

rint-f

r i n t f CT Co

"HP_

Fi 1 en CALL

Badda

IF Pr

Fi 1 en CALL

Badda

IF Pr

"HP

Fi 1 en CALL

Badda

IF Pr

Fi 1 en CALL

Badda

IF Pr

"CH._

Fi len

CALL

Badda

IF Pr

Fi 1 en CALL

Badda

IF Pr

ELBE

PRINT

BEEP

PAUSE

SELEC

lag THEN PRINTER IS Printer

lag THEN PRINT "CALIBRATION DATA FOR THE FOLLOWING IS LOADED:

upl er_i dt

778D" I 30 to 2000 MHz.

ame*="HP__778D_-f "5<Sourcedi sk*

Enter__caldata(Filename*,Coup_inc (*) ,Cal_id#, Inc_jDts)

ta _id.|-(l )=Cal_idf

intflag THEN PRINT Cal_.id*

ar(ie$="HP_77BD_r "?<Sourcedi sk*

£nter_caldata(Filename*.Coup_re-fl (*) ,Cal_id*,Retl_pts)

ta_id*(2)=Cal...id*

intflag THEN PRINT Cal_id*

11692D" I 2 to 18 GHz

aiT,e*="HPl 1692D_-f "?<SoLircedi sk-T Enter_cal data (Fi 1 enamef , Coup_i nc (*) ,Cal _i d*- , Inc_pts)

ta_idt(l)=Cal._id*

int-flag THEN PRINT Cal_id*

amet= " HP 1 1 692D._r " ?<3our ced i sk*

Enter_caldata (Fi 1 ename* ,Coup_re-f 1 (*) ,Cal _id* ,Ref 1 _pt5)

ta_idt (2) =Cal_id*

int-flag THEN PRINT Cal_idt

130._4" I 1 to 30 MHz Anzac bi-directional

anie*="CH130__4,_-f 1 "?/Sourcedi skiEnter cal data(Filename*,Coup_inc(*),Cal_id*,Inc_pts)

ta_idJF(l)=C3l_id:|

intflag THEN PRINT Cal_.id*

ame*="CH130_ 4__r 1 "SSourcedi si:;* Enter ._cal data (Fi 1 ename* , Coup_re f 1 (*) , Cal _i d* , Re-f 1 _pts ) ta ,id-t- (2)=Cal._id*

intflag THEN PRINT Cal._id:t^

"COUPLER CALIBRATION DATA ERROR NOT DEFINED. "

92
938

940

942

944

946

948

950

952

954

956

958

960

962

964

966

963

970

972

974

976 I 978

980

982

984

986

988

990

992

994

996

998

1000

1002

1004

1006

iOOS

1010

1012

1014

1016

1018

1020

1022

1024

1026

1 028

1030

1032

1 034

1036

1 038

1040

1042

1044

1046

1 048

1050

1052

1054

1056

FT<IN[ lABXYd , 18) ;FPT:f ( " ",80);

RETURN

/ / / / / / / / / / / / / / / / ////////////////////////////////////////////

oad cal _data:

PRir-JT TABXV (1 , 18) ;RPT:t ("*" ,20) ; " LOA[,> CALIBRATION DATA "; RPT^t^ ("*"', 20)

DISP " Put ' CALIBRATION DATA Zi SUB Program' disk in "

;

SELECT Scurcedisk*

CASE ": INTERNAL, 4,0"

DISP "RIGHT DRIVE, "; CASE ": INTERNAL, 4, 1" DISP "LEFT DRIVE, "; END SELECT

DISP "hut ' Cont i nue-k5 ' . " BEEP

ON KEY 5 LABEL " Cont i nue" , Local _prtv GOTO Calloads

LOOP

END LOOP

alloadsiOFF KEY

DISP " Calibration DATA -for Cables, Couplers, F'ads , etc. now LOADING '

Install new calibration -files herel

IF Print-flag THEN PRINTER IS Printer

IF Print-flag THEN PRINT "CALIBRATION DATA FOR THE FOLLOWING IS LOADED:

Fi 1 enamef=

CALL Enter

Baddata_ i d IF Printfl

I Fi lenafrie* = CALL Enter

Baddata_i d IF Print-fl

Fi 1 enafTie-$ = CALL Enter

Baddata_i

d

IF Printfl

Fi 1 ename*=

CALL Enter

Bsddata id

IF Printfl

Fi 1 ename*=

CALL Enter

Baddata_i d IF Printfl

Fi 1 ename-f = CALL Enter

Baddata__i d IF Printfl

"Cable6FT_l "?-Sourcedi si::* _caldata(Fil ename* ,Cable6_l (,*) ,Cal _idt-,C6_

$(3)=Cal_id*

ag THEN PRINT Cal_id*

.Ipts)

" Cab 1 e6FT_6 " ?<Sour c ed i sk*

_caldata (Fi 1 ename* ,Cabl e6_6 (*) ,Cal _i d* , C6_6pt5)

*(4)=Cal„idf

ag THEN PRINT Cal_id.J:

"Cable4FT_2"?<Sourcedi skf

_c al data (Filename*, Cab le4_2(*) ,Cal _id*, C4_2pts)

*(5)=Cal_id$

ag THEN PRINT Cal_id*

"Cable4FT_4"!5<Sourcedi5k*

_caldata(Fi lename*,CabIe4_4 (•*) ,Cal _id* ,C4_4pts)

•*(6)=Cal_id*

ag THEN PRINT Cal_id.t-

" Cab 1 e 1 0F_3 " ?<Sour cedi sk*

_caldata (Fi 1 ename* , Cabl el0._3 (*) , Cal __i d* , CI

*(7)=Cal_.idt

ag THEN PRINT Cal..id*

0_3pt5)

"Cabl el0F_5"S'.Sourcedi sl^

_ cal data (Fi 1 ename* , Cabl el0..5 (*) , Cal ._i d* , C10_5pt5)

t (8)=Cal_id$

ag THEhJ PRINT Cal_.id*

Fi lename*="Cable5FT 7"?<Eoar cedi sk'*

93
I OSS

1060

1062

1064

1066

1 063

1 070

1072

1074

1076

1073

1 080

1032

1084

10S6

1033

1090

1092

1094

1096

1098

100

1102

1104

1 1 06

IOS

1110

1112

1114

1116

1118

1120

1122

1124

1126

1123

1

30

1132

1134

1136

1138

1140

1142

1144

1146

1 143

1150

1 152

1 154

1156

1153

1 1 60

1 1 62

1164

1 166

1168

1170

1172

1174

1 176

CALL En tsr _ c ^ 1 d ? t a ( F 1 1 engine* , Cab 1 e5_7 ( * ) , Ca 1 _i d* ,

Baddata i d* '/v ) =Cal __id* IF Printflaq THEn PRINT Cal id*

.7pts)

F i 1 BnaiTiG'-t— " PAD _S 6770 " 'iSou.rcc'd i z\."i- CALL Enter_caidata(Fi 1 ename*: ,Pad_56770 (*) , Cal _i d4^ , Pad5_pts ) Baddata_i df i 10) =Cal _i d$

IF Print-flag THEN PRINT Cal_id*

I Fi 1 ename$="F'AD__5530"S'.Sou.rcedi sl:'^- CALL £nter_caldata(Fi 1 ename* , Pad._-f 5530 (*) , Cal _i d *: , Padf _p.t5)

Baddata._i d* ( 1 1 ) =Cal _i ds

IF Print flag THEN PRINT Cal_id*

I Fi lename*;="PdAS6A1466"wSourcedi sk*

CALL Enter_caldata (Fi 1 ename-f , Pad_a5 6a <*) ,Cal_ id* ,Pada_pts)

Baddata_id*(12)=Cal_id$

IF Print-flag THEN PRINT Cal_id*

I Filename*="ANZAC_JCT"?<3ourcedist :f CALL Enter_caldata(Filename*,H_jct (*) , Cal_i d* , Jct_pts)

Baddata_id*(13)=Cal_id*

IF Printflag THEN PRINT Cal_id*

1 Fi 1 ename$="Rcabl e4-f t "?'.Sourcedi sk-f CALL Enter_caldata(Filena-Tiet,Cable._r4 (-*-)

, Cal _i d* , Cr4pts)

Baddat a__i d* ( 1 4 ) =Cal _ i d*

IF Printflag THEN PRINT Cal_id-f

I Fi lenafrie*="Rcabl el2-f t "'-Sourcedi st:f- CALL Enter_caldata (Fi 1 ename* , Cabl e_r 12 (*) , Cal _i d* , Cr 12pts)

Baddata_id* (15.' =Cal_id$

IF Printflag THEN PRINT Ca l._id*

IF Printflag THEN

PRINT RPT*("_" ,30)

PRINT USING "4/"

END IF DI3P " Calibration DATA LOADED " WAIT 1 PRINTER IS CRT

CALL Wipe_clean

RETURN

////////////////////////////////////////////////////////////

Fi 1 1 cal i brat 1 on : ' Determine the cable, coup'" r and pad calibration

I values for each frequer.

! Save these in the adjust («) file for use by the

' measurement routine.

IF Buql THEN

PR INT T I ME:f ( T I MEDrn E ) ; PRINT RPT-t ("<" , 15) ; " FILL CALIBRATION MATRIX " ; RPT* ( " > "

, 15)

END IF DISP "NOW Filling Calibration matri;:."

ALLOCATE Ad just (Ftotal , Cal i b_i terns

Fcount=

FOR Frequency=Fstart JO Fstop STEP Fstep

CALL Get _cal_vaIue(F"req LI enc/,Cou Dine, Coup _inc(*),Baddata,Inc_pt5)

94
1173 IF Baddata THEN

1 ISO C'jl ._.i df =Baddata_.i dt ( 1) IISI' SGSUB Flaqbaddata

11S4 END IF

1 186 f4d jLiE-t (Fcount , 1 ) =Coupi nc use I 1190 CALL Get_cal _val ue (Frequency , Couipre-f 1 ,Coup re-fl (*) , Baddata , Rer 1 _ptB)

1192 IF Baddata THEN

1 194 Cal _ idt=E:addata id$ (2)

119.i GaSUB Flaqbaddata

1198 END IF 1200 Adjust (Fcount ,2) =Coupref

1

1202 I 1204 CALL Get_cal._v5lue(Frequency ,C6_llos5,Cable6_l (*> , Baddata , C6 1 pts ) 1206 IF Baddata THEN

1208 Cal__id*=Baddata__id* (3)

1210 GQSUB Flagbaddata

1212 END IF 1214 Adjust (Fcount, 3) =C6_11 OSS

1216 ! 1218 CALL Get _cal_.,value (Frequency, C6_61 OSS, Cable6.._6 (*) , Baddata , C6_6pt5)

1220 IF Baddata THEN

1222 Cal_id*=Baddata_id*(4)

1224 GOSUB Flagbaddata

1226 END IF 1223 Adjust (Fcount ,4)=C6_61os5

1230 I 1232 CALL Get_cal_value (Frequency ,C4_21oss,Cable4_2 (*) , Baddata , C4_2pt5)

1234 IF Baddata THEN

1236 Cal_id*=Baddata_id-t (5)

1233 GOSUB Flagbaddata

1240 END IF 1242 Adjust (Fcount ,5) ==C4_21o55

1 244 ! 1246 CALL Get_caI_value(Frequency,C4_41o5S,Cable4_4(*) , Baddata , C4_,4pt5 ) 1248 IF Baddata THEN

1250 Cal id*=Baddata_id*(6>

1252 GGSUB Flagbaddata

1254 END IF 1256 Adjust (Fcount ,6) =C4_41oss

1 258

1260 CALL Get_cal_value (Frequency , C10_3I oss , Cabl el0._3 ( > , Baddata , C 10_3pts ) 1262 IF Baddata THEN

1264 Cal _id*^Baddata..idt (7)

1266 GQSUB Flagbaddata

1268 EI-JD IF

1 270 Ad J u 5t ( Fc oun t , 7 ) =C 1 0_3 loss

1272 ! 1274 CALL Get_cal_value 'Frequency, C10_51oss, Cablel0__5 (*) , Baddata ,C10_,5pts ) 1276 IF Baddata THEN

1276 Cal__.id* = Baddata^>d4:: (S)

1280 GOSUB Flagbaddata

1202 END IF 1234 Adjust (Fcount ,8) =C10_5Ioss

1236 I 1288 CALL Get_cal_,value(Frequency ,C5. 71os5,CabIe5__7 (*) , Baddata , C5_7pts ) 1290 IF Baddata THEN

1292 Cal_.idt=Baddata__idf (9)

1294 GOSUB Flagbaddata

1296 END IF

95
i93

'00

' (") ^ ?04

;.06

? 1 :i2

r.i4 us

'.20

T »": ">

;.24 '•26 ?2a

>38

>40

'42

^44

546

'.48

54

356

358

360

3.62 364

366

363

370

372

:74

.'76 :;78 380

382

334

336

383

390

392

.394

.396

598

. 4 00

402

.404

.406

L 4oa

. 4 1 .412

,414

.416

Adjust (f-c-ount ,91 =C5._71 oss

I CALL Gct_cal va] ue (Frequency , F'ad5_l OEE ,F 'ad _b67 70 (*) , Esddata ,Fadz__ptt:'. IF Baadata THEN

Lai _id*=Baddata .Id* (10)

GQSUB Flagbaddata

END IF Ad .J List (Fcount , 10 ) =Pads_l OSS

CALL Get cal _valu.2 (Frequency , F'adt _ 1 oes, Pad _-f 5530 (* ) , Baddata , PadT_p.t£ i IF Baddata THEN

Cal _i df = Baddata_.i d$(l 1 > bOSLlB Flagbaddata

END IF Ad lust (Fcount ,11) =Pad-f _Ios5

I CALL Get_cal _val ue (Frequency , F'ada_l os= , F'ad_as6a (* ) , Bad 'data ^F'ada pts)

IF Baddata THEN

Cal_id*=Baddata._id* ( 12)

GOSUB Flagbaddata

END IF Adjust (Fcount ,12) =Pada_l os5

CALL Get_cal_value (Frequency , Jet __1 oss , H_jct () , Baddata ,.lct_pte)

IF Baddata THEN

Cal _id$=Baddata_ i d* (13)

GOSUB Flagbaddata

END IF Adjust (Fcount, 13 ) ^.Jct_l oss CALL Get.cal _val ue (Frequenc / , Cr41 oss , Cabl e__r4 (*) , Baddata , Cr4ptE)

IF Baddata THEN

Cal ...i d*--Baddata__i d* (14)

GOSUB Flagbaddata

END IF Adjust (Fcount ,14) =Cr41os5

CALL Get_cal _value (Frequency , Cr 121 oss , Cabl e_r 12 (*) , Baddata , Cr 1 2pts)

IF Baddata THEN

Cal_idf=Baddata_id* (15)

GOSUB Flagbaddata

END IF Ad just (Fcount , 15) =Cr 121 oss

I Fcount=Fcount+l

NEXT Frequency

DISF' "NOW Tabulating calibration values."

G03US Printcal values

DISP CHP:r(12)

RETURfJ

! //////////.' //«***FLAG BAD DATA****/ ////// V /////////////// //

I Fl agbci.ddata : ! In-f of^m the operator that there i e wrong data

! being brought back from Enter __cal __data

I PRINTER IS Printer

PRINT RPTf ( "*" ,5) ; " NO CAL DATA at ";Frequency;

PRINT " MHn : ";Cal_id*

BEEP

96
1413

1420

1422

1424

1426

1423

1430

1432

1434

143o

1433

1440

1442

1444

1446

1443

1450

1452

1454

1456

1458

1460

1462

1464

1466

1468

1470

1472

1474

1476

1473

14B0

1432

1484

1436

4488

1490

1492

1494

1496

1493

1500

1502

1 504

1506

1508

1510

1512

1514

1516

1513

1520

1522

1524

1526

1528

1530

1532

1534

1536

PRINTER

RETURN

IS CRT

I Pnntca lvalues: I MAKE LIST OF'

IS F-T inter

,24)

' / / ////// / / / / / / / / / / / / / / / / / / / / / /

/

CALIDRATIUN VALUES USED.

PRINTER

PRINT

PRINT RPTf(

PRINT

CALIBRATION / LOSS VALUES (dB) " ; RPT* ( "* " , 24

)

PRINT

PRINT

PRINT

PRINT

-first

"Frequency

hal-f of the

Coupl er

Re-f 1

val ues

.

MHz Fward

"10ft#5 5ft#7"

Loss-fmtl: IMAGE M5D. D , X , 2 (MDD. DD , X ) ,X,2(MD

Los5fmt2: IMAGE 5(MDD.DD,X)

Fcount=l

FDR Frequency-Fstart TO Fstop STEP Fste

Coupinc=10*LGT (Adjust (Fcount , 1 )

)

Coupre-f 1=10*LGT (Adjust (Fcount ,2) ) C6_.lloss=10*LGT (Adjust (Fcount ,3) ) C6_61oss=10*LGT (Adjust (Fcount ,4)

)

C4_21o55--10*LGT (Adjust (Fcount ,5) ) C4_41oss=10*LGT (Adjust (Fcount ,6)

)

C10_31oss=10*LGT (Adjust (Fcount ,7)

)

C10._51o5E=10*LGT (Adjust (Fcount ,8) ) C5._"71oss=10*LGT (Adjust (Fcount ,9) ) PRINT USING Lossfmtl ; Frequency , Coup

PRINT USING Lo5sfmt2;C4_21os5,C4__41

Fcount=Fcount+l

NEXT Frequency

PRINT RPT*("-" ,80)

BLUE CABLES

6-Ft#l 6tttt6 4ft#2 4tt#4 lOfttt'

D.DD,X) ,,#

! Coupler incident

! Coupler reflected

!6 foot BLUE cable

!6 foot BLUE cable

!4 foot BLUE cable

!4 foot BLUE cable

! 10 foot BLUE cable #3

110 foot BLUE cable #5

!4 foot BLUE cable #4

inc ,Coupref 1, C6_l 1 oss, C6_61 oss OSS , C 1 0_31 oss , C 1 0_51 oss , C5._71 <^55

#1

#6

tt2 #4

PRINT

last half of the values.

PRINT "Frequency S6770 F5530 ASA6A

PRINT " MHz pad pad pad

Lossf mt3: IMAGE M5D.D, X,2(MDD. DD , X) ,X,MDD.

Lo55fmt4: IMAGE 3(MDD.DD,X)

Fcount=l

FOR Frequency=Fstart TO Fstop STEP Fste

Pads_Ioss=10*LGT (Adjust (Fcount , 10)

)

Padf __loss=10*LGT (Adjust (Fcount ,11))

Pada Ioss=10*LGT (Adjust (Fcount , 12)

)

Jct_lo55=10*LGT (Adjust (Fcount, 13)

)

Cr 4 1 05S= 1 0*LGT ( Ad j ust ( Fc oun t , 1 4 ) ) Cr 121os5=10*LGT (Adjust (Fcount , 15)

)

PRINT USING Lossf rrit3: Frequency , Pads

PRINT USING Lossf mt

4

Fcount =F count +

1

NEXT Frequency

PRINT RPT*("*",30)

PRINT

PRINTER IS CRT

RETURN

HJct

loss

DD,X,tt

Semi -F"<i gi d

4ft 12ft"

Jct_loss,Cr41oi

IWeinschel S6770 lOdB pad

IWeinschel F5530 lOdB pad

IWeinschel AS6A-1466 lOdB

!Anz ac Hybrid Junction

! 4ft Rigid coax

! 12ft Rigid cc>a;;

1 oss , Padf _1 oss , F'ada_.l oss

i5,Crl21os5

97
1540

1542

1544

1546

1543

1 550

1552

1554

155<b

1 55S

1560

1 562

1564

1 566

156B

1 570

1572

1574

1576

1573

1580

1582

1584

1536

1583

1590

1592

1594

1596

1598

1600

1602

1604

1 606

1608

1610

1612

1614

1616

1613

1620

1622

1624

1626

1628

1630

1632

1634

1 636

163S

1640

1642

1644

1646

1648

1650

1652

1654

1656

! / / / / / / / ' / / ////////////////// / / / / / / / / / / ///////// / / / / / / / / / / / /

/

E;ctract_cald5t5: I Get all calibration data -For this

! "f r5~Lienc V . Calibration data -for all cables, probes, ?< power heeds.

Pw

Pv,

1 Co

C6

C6

C4

C4

CI

CI

C5

Pa

Pa

vJC Cr

Cr

RE

^-lT•trcal l=FMpwriTitrcal 1 ( (Frequency) ) rmtrcal2-=FNPwr'Titrcal 2 ' (Frequency) ) upinc=Adjust (Fcount

,

u.pre-f 1 =Ad just (Fcount

lloss=Adju5t (Fcount

61oss=Adjust (Fcount

21 oss=Md just (Fcount

_41 053=Ad just (Fcount

0_31 oss=Ad just (Fcoun

0_51 oss=Ad j ust ( Fcoun

_71 o£s=Ad just (Fcount

ds_l oss=Ad just (Fcoun

d-f _1 oss=Ad just (Fcoun

da_l 05==Ad just (Fcoun

t_l osE=Ad just (Fcount

41 o5==Ad just (Fcount

,

121 o = E=Ad just (Fcount

TiJRN

1)

,2)

,3)

,4)

,5)

,6)

t,7)

t,S)

-.9) t , 1 ) t, 11)

t , 12)

,13)

14)

,15)

I 18 GHz HEAD.

!26 GHz HEAD.

Coupler incident

Coupler re-flected

6 -foot BLUE cable #1

6 -foot BLUE cable #6 rcvr . 4 -Foot BLUE cable #2

4 -foot BLUE cable #4

10 -foot BLUE cable #3

10 -foot BLUE cable #5

5 foot BLUE cable #7

Weinschel S6770 lOdB pad

Weinschel F5530 lOdE pad

Weinschel A36A-1466 lOdB

Anzac Hybrid Junction

4-ft Semi-rigid coax lines

12-ft Semi-rigid coax lines

! ////////////////////////////////////////////////////////////

I Fl ip_pri nt-f 1 aq: ! DISP " Toggle PRINTING o-F measurement data. " Waittime=fiMEDATE

LOOP

IF Print-flaq2 THEN

ON KEY LABEL "P'-int is ON" , Local _prty GOSUB Togqleprint

ELSE

ON KEY LABEL "Print is OFF" , Local _prty BCSUE Toccleprint

END IF EXIT IF TIMEDATE-Waittime>4

END LOOP

DISP CHR*(12)

OFF KEY

RETURN

Toggleprint:

IF PrintTlag2 THEN

Printf lag2=0

ELSE

Printf lag2=l

END IF

RETURN

!/////////// / / / / / / / / / /****PERFDRM MEASUREMEN1 S**** ///////////////

I Do_rrieasurei'nerits : !

IF Bugl THEN

PRINT TIMEJ (TIMEDATE) ;RPT* t"<" ,20) ;

'" DO MEASUREMENTS "; RPT:t ('>", 20)

END IF

98
1 65B I Initialize insti^uments

1660 remote: §Siq_qen

1662 IF Fp436al OR Fp436a2 THEM CALL MBnu_jJwr43fca ' Set up 436A pwr mtrs

1664 IF Fv3456al THEN CALL Setdvm_3456a ((Sbvml)

1666 IF Fv3456a2 THEN CALL Setdvm_3456a (@Dv(7i2

)

1663 IF Fv3473al THEN CALL Setdvm_347aa ((2Dvfr,3) 1670 IF F5a8565b THEN CALL Special zr__5etup (©Spec _ al z r ) 1672 IF Test_type:t:: >"OTHER (NG STER3)" THEN

1674 CALL Initial i-emotor (©Motor

)

1676 CALL Zeromotor (©Motor)

1678 END IF 16S0 IF Test_type*="MODE TUNE EMISSIONS" THEN

1682 CALL Set__dbm (-140,0, @Sig_.gen) ! EUT is the source

1684 END IF 1686 ! 1683 ! 1690 ColLimn=l

1692 Beginstep=Begi n_step

1694 Steps=Begin_step -1 1696 REF'EAT I measureiTients -for all steps or once for non-steppinq type.

1693 Steps=Steps+l

1700 ! 1702 IF (Steps-l > /40.=INT( (Steps-l) /40. ) OR Steps=Begi n_5tep THEN

1704 IF Test_type*="MODE TUNE EMISSIONS" THEN

1706 GOSUB Fl ip_print-f lag I includes WAIT action.

L708 ELSE

1710 GOSUB Read_2er o_-F 1 el d I -for all enabled instruments.

L712 END IF 1714 ELSE

1716 GD3UB Flip_print-f lag

1718 END IF 1720 ! 1722 ! ZERO Readings or WAIT complete

1724 ! 1726 IF Total _chans< 1 THEN ! Print single header -for all -Frequencies

1728 IF Printflag AND Print-flag2 THEN GOSUB Pr i nt_headi nf o 1730 END IF 1732 IF Te5t_type*<>"M0DE TUNE EMISSIONS" THEN ! Restore power

1734 CALL Set_-freq ( (Frequency) ,eSig_gen)

1736 CALL Set_dbm(Dbm, 1 ,@Sig_gen)

1738 END IF 1740 I 1742 ! Measure all -frequencies

1744 ! 1746 Fcount=l

1748 FOR Frequency=F5tart TO Fstop STEP Fstep

1750 DISP CHR*(129)

1752 DISP " TIME: "

; TIME* ( T IMEDATE)

;

1754 IF Test_type#="OTHER (NO STEPS)" THEN

1756 DISP " Now Testinq: FREQUENCY ="; Frequency ; " MHz. " 1753 ELSE

1760 DISP " TUNER STEP ";Steps;", FREQUENCY ="; Frequency ; " MHz,

1762 END IF 1764 GOSUB E;;tract_caldata ' Get all calibration data for this

1766 ' -frequency.

1768 Rawdata ( 1 ,Col umn) =Frequency

1770 IF Te5t._type*<>"M0DE TUNE EMISSIONS" THEN

1772 CALL Set _-freq ( (Frequency) , (5Si g_gen ) 1774 END IF 1776 IF Search eut THEN GOSUB Level eut out

99
17 73

1780

1782

1734

1736

1788

1790

1792

1794

1796

1798

1800

1S02

1804

1806

1803

1810

1812

1814

1816

1818

1820

1822

1824

1B26

1828

1830

1832

1834

1836

1833

1840

1842

1844

1846

1848

1850

1352

1854

1856

1853

1860

1362

1864

1866

1868

1370

1872

1874

1876

1873

1880

1332

1884

1836

1838

1890

1892

1894

1896

IF Search_pwr THEN GQSUB

GOCUB Read meters

Level net i nput

Read all enabled i nstruiTi6?nts.

See Conf i gure_instr -for changes.

Calibration data is applied there

via AppI y_cal _data.

! FILL the DATA -file

Fi 1 1 _data -f i 1 e: I **<** Mal:;e sure this assignment matches de-fns.

SELECT Test_type*

CASE "MODE TUNE REGULAR"

Rawdata (2 , Col umn ) =P1

Rawdata (3 , Col umn ) =P2

Rawdata ( 4 , Col umn ) =Sa_pwr

CASE "MODE TUNE EMISSIONS"

Rawdata ( 1 ,Column ) =3a_pwr

CASE "OTHER (NO STEPS)"

Rawdata (2, Column ) =P1

Rawdata ( 3 , Coi umn > =P2

Rawdata (4 , Col umn ) =V1

END SELECT

IIF Total ..Chans; THEN

FOR P=Total_meters+2 TO Total _chans+Total _meters+l

Rawdata (P, Col umn ) =Probe_v_m (P-Total _meters- 1

NEXT P END IF

IF Print-flag AND Printtlag2 THEN

IF Total _chans>0 THEN 60SUB Print.

GOSUB Printrawdata

END IF Column=Col umn+l

Fcount=Fcount + 1 NEXT Frequency

headi n-Fo

ALL frequencies measured

IF Test_typet-="OTHER (NO STEPS)" THEN

GOSUB Save_data

ELSE

PRINT TIME* (TIMEDATE) ; " ...Step number "; St eps ; " completed....

IF (Column+Ftotal-l >Fi le20steps) OR (Steps=Tuner _5teps ) THEN

Endstep=Steps

GOSUB Save _d at

Begi nstep=Endstep+

Col umn=l

MAT Rawdata= Rawdata* (0.)

END IF CALL Movemotor (©Motor

END IF UNTIL Steps > = Tuner_steps OR Te3t_type*=-"0THER (NO STEPS)"

rIF Test_typet<;"MODE TUNE EMISSIONS" THEN

CALL Set_dbm ( - 1 40 , , (§Si g_.gen ) END IF LOCAL 7

RETURN ! ALL Measurements complete.

I

' ////////////////////////////////////////////////////////////

100
1S9S

1 9(.")0 1902

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20 1

6

Readzero_t i el d : ! PRINT TIMEJr-dir-IEDATE) ; " Step number "; Steps; "

, zero metErs."

Measure all zero -field values

CALL Set.._dbm (-140 , , ©Si g._qen ) IF F'p436al AND Fp436a2 THEN

CALL Zero_pwr_mtrs (<3Si q _gen , ©Pwr 1 ,@Pi\(r2)

ELSE

IF Fp436al THEN CALL Zero_pwr_mtrs (feSi g_gen , ©Pwr 1

)

IF Fp436a2 THEN CALL Zero_pwr__mtrs (@Si g._gen , SPwrZ)

END IF IF Fp433al THEN

Ab*="AE-f"

CALL Zero_43Sa(@Dual._pwr 1 ,Ab*)

END IF

IF Fp433a2 THEN

Ab*="A"

CALL Zero_438a(@Dual_pwr2,Ab*)

END IF

IF Fv3456al THEN CALL Readdvm ( Z3456al , ©Dvml

)

IF Fv3456a2 THEN CALL Readdvn ( Z3456a2 , @Dvm2)

IF Fv3473al THEN CALL Readdvm ( Z3478al , @Dvm3)

IF Buql THEN

PRINTER IS Printer

PRINT "Zeros DVM1=" ; Z3456al ; "

, DVM2=" ; Z3456a2; " DVM3=" ; Z3473a

1

PRINTER IS CRT

END IF

Fill F'robe _vol ts (30) using Probe_addr (*) and Total_chans

IF Total __chans>0 THEN

MAT Probe_zero= <0)

CALL Read _pr obes (@Gpio)

MAT F'robe_zero= Probe_voIts

IF MAX (Probe_zero(*) ) >10 OR MIN (Probe_zero (*) ) <-10 THEN

PRINT TIME*(TIMEDATE) ; " ... "; PRINT " WARNING ... Check Multiprobe zero ******** " END IF END IF RETURN

///////////// APPLY CALIBRATION TO MEASUREMENT DATA ////////

Appl y_cal _data: I For listing o-f valid variable names

I see E;;tract_cal data. Values are in ratio -forni.

Ca. 1 jD ower 1 _2 : I Pl=Power l*Coupinc*Pwrmtrcal l*PadT _1 oss/ ( CI 31 oss*Pad5_l oss)

P2=Power2*Coupre-f 1 *F'wrmtrcal 1*C10_31 oss*Pads_l oss RETURN

Cal JD ower 34:

P3=Power3

P4=Power4

RETURN

Cal _power 5: P5=Power5

RETURN

101
2018 I 2020 Calpower 6:

2i;'22 F'6=F'ower6

2024 RETURhJ

2026 ! 2023 Cal _55_power :

2030 Sa_pwr=Sa_power-KC10 .51 055*C4_21 oss*C4_41 ose 2032 RETURN

2034 ! 2036 ! 2038 ! ///////////////////////////////////////////////./////////////

2040 ! 2042 R£?ad ^meters: I Control module -for all instrument reads.

2044 Too_hot=0

2046 P1=0

2048 P2=0

2050 Checl:time=TIMEDATE

2052 ! 2054 Hp438a_l :

2056 IF Fp43aal THEN

2058 GOSUE Power _1_2 I HP438A both channels

2060 ! returns Powerl, F'ower2 (watts)

2062 IF Toc_hot THEN GOTO Read_meter5

2064 GOSUB Cal _power_l_2 I correct for losses and return P1,P2

2066 Min_power:IF (Pl-P2)<Mi n_pwr THEN

2068 BEEP

2070 PRINTER IS Printer

2072 PRINT TIME*(TIMEDATE> ; " " 2074 PRINT RPT*("-" ,40) ; " INPUT IS TOO LOW ! " 2076 PRINT "Raw Pl = " ; Power 1 ; " * Cal P1 = ";P1

2078 PRINT "Raw P2=" ; Power 2; " ** Cal P2=";P2

2080 PRINT "N€jt input power (P1-P2) =";P1-P2

2082 PRINT RPT*("-",40)

2034 PRINTER IS CRT

2086 GOSUB Ad.iust_power

2033 GOTO Read_meters

2090 END IF 2092 END IF 2094 1 2096 Hp43aa_2:

2090 IF Fp438a2 THEN

2100 GOSUB Power_3_4 ! Set -for channel A (Power3) only, Power4=0

2102 ! returns Power3, Power4 (watts)

2104 IF Too__hot THEN GOTO Read_meters

2106 GOSUB Cal _power_3_4 I correct -for losses and return P3 , P4

2103 END IF 2110 ' 2112 Hp436a_l :

' 2114 IF Fp436al "I HEN

2116 GOSUB Power__5 ! HP 436A

2113 I returns Power

2120 IF Too_hot THEN GOTO Read_meters

2122 GOSUB Cal_power_5 ! correct -for losses and return P5

2124 END IF 2126 ! 2123 Hp436a__2: ' 2130 IF Fp'436a2 THEN

2132 GOSUB Power _6 ' HP 436

2134 I returns F'ower6

2136 IF Too hot THEN GOTO Read meters

102
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GDSUB Cal power _6

END IF correct tor losses and retLirn P6

223 O

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2250

2252

2254

2256

Mbs probes: I IF Total _chan5>0 THEN GOSUB Probe_rd

IF Too hot THEN GOTO Read meters

! Multi probe system

! returns corrected V/in,

Wai t_ 1 oop : ! LOOP

EXIT IF (TIMEDATE-Checktime) >Time„eut

END LOOP

Hp3456a_l: I ======

IF Fv3456al THEN

CALL Readdvm (Vol t 1 ,@Dvml

)

EUT connected to this dvm. ==

HP digital voltmeter

returns Volts (DC volts)

Vl=Voltl-Z3456al correct -for zero, yields VI

IF Vl>Ma;; .eut THEN

PRINTER IS Printer

PRINT TIME*(TIMEDATE) ; ". . .DVMl error / EUT overload. " PRINT "Set ma:; = " ;Ma;;_eut; "

, Readi ng=" ; Vol 1 1 ; ", Zero-" ; Z3456al

PRINT ", Adjusted reading=";Vl

PRINTER IS CRT

GOSUB Reduce_power

GOTO Read_meters

END IF END IF Hp3456a_2: ! IF Fv3456a2 THEN

CALL Readdvm(Volt2,©Dvm2)

V2=Volt2-Z3456a2

END IF

HP digital voltmeter

returns Volts (DC volts)

correct -for zero, yields v:;

Hp3478a_l:

IF Fv347Sal THEN

CALL Readdvm(Volt3,(aDvm3)

V3=Volt3-Z3478al

END IF

HP digital voltmeter

returns Volts (DC volts)

correct -for zero, yields V^

22 Hp59306a_relay:

:24

J26

;28

An example o-f using the relay to measure multiple

quantities. This requires additional instrument to

actually do the measurements, as the relay only controls

a systemi o-f rf switches.

In this example, turn o-f-f the Spectrum Analyzer -flag. IF Fr 59306a THEN

OUTPUT (^Rlyl; "A123" I Toggle to SUM port

CALL Spec al zr __start (Frequency , @Spec al zr ) CALL Special zr__read (Sapower , Frequericy ,(S3pec_ al zr ) Sa_power=10. 0-- ( (3a_power / 10. 0) -3„ 0) I dBm -> watts

GOSUE< Cal _sa_j:'Ower I correct tor losses and return Sa__pwr

Sum_j30wer=3a _pwr

OUTPUT (aplyl; "B123" ! Toggle to DIFFERENCE port

CALL Spec_al zr_start (Frequency , (2Spec._al zr ) CALL Spec_al zr_read (Sa_power , Frequency , (sSpecal z r ) Sa_power=10. O'^ ( (Sa_power/10. O) -3. 0) ' dBm -> watts

GOSUB Cal _sa_power I correct -for losses and return Sa_pwr

103
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235(1) 2352

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2370

2372

2374

2376

Di -f -f _power--Sa_jDwr

END IF Spec a 1 zr : ! IF Fsa8566b AND NOT Fr59306a THEN ! HP8566r3 Spectrum analyzer

CALL Spec _al zr_start (Frequency , @Spec_al zr

)

CALL Spec_ al zrread (Sa_ power , Frequency , ©Spec _al zr

)

Sa _power = 10. ( (Sa_power/ 10. O) -3. 0) ' dBm -> watts

GOSUB Cal sa_power I correct for losses and return Sa_pwr

END IF RETURN

//////////// Read instrument subroutines ///////////////////

HF' 43BA Dual power meter — @Dual_pwrl

Power_l ._2: Ab:f="AB"

CALL Read dual jjwr ( Ab^ , Apower , Bpower , Too _hot , Val i d , ©Dual _pwr 1

)

IF Too_hot THEN

GOSUB Reduce_power

RETURN

END IF IF NOT Valid AND NOT Too_hot THEN

GOSUB Dual _pwr _error

GOTO Power_l_2 I Repeat measurements

END IF

IF Ab*="AB" OR Ab*="A" THEN

IF Apower<0. THEN Apower=0.

Power 1=Apower

END IF

IF Ab*="AB" OR Ab*="B" THEN

IF Bpower<0. THEN Bpower=0-

F'ower 2=Bpower

END IF RETURN

Power detector; re not sources

HF' 438A Dual power meter - @Dual_pwr;

F'ower_3_4: Ab$="A" ! or Ab*="AB" i -f you want both channels.

CALL Read_dual _pwr (Ab* , Apower , Bpower , Too_hot , Val i d , ODual __pwr2) IF Too_hot THEN

GOSUB Reduce_power

RETURN

END IF IF ND\ Valid AND NOT Too _hot THEN

GOSUB Dual __pwr _err or GOTO Power 3 _4 I Repeat measurements

END IF

IF Ah|:=="AB" OR Ab4?="A" THEN

IF ApowGr<0. THEN Apower=0.

Power 3=Apower

END IF

IF Ab*="AB" OR Ab*="B" THEN

IF Bpower -O. THEN Bpower--0.

F'ower4 = E;power

END IF RETURN

I

! HP 436A Power meter - (sPwr 1

F'ower detectors are not sources

104
237S

2380

2382

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2496

F'ovier 5: ! F'wr i d-t="Pl " CALL Re£<d _pwr iTieter (Power , Pwr _i d* , Val i d , @Pwr 1 , ©Si q_ gen ) IF NOT Valid THEN

DISP "ERROR IN 436a POWER METER 1" BEEP

PAUSE

Power =0.

Too_hot=l

END IF IF Power<0. THEN Power=0.

Power 5=Power

RETURN

HP 436A F'ower meter @Pwr2

F'ower _6; ! Pwr__i d-t="F'6"

CALL Read_pwr meter (Power , Pwr _i dit , Val id , (SPwr2 , (SSi q_gen > IF NOT Valid THEN

DISP "ERROR IN 436a POWER METER 2"

BEEP

PAUSE

Power =0.

Too_hot=l

END IF IF Power ::0. THEN Power = 0. F'ower 6 =F'ower

RETURN

NBS Multi probe system

Probe _rd: I IF Total _chans>0 THEN

CALL Read _p robes (@Gpi o)

Too_hot=0

FOR P=l TO Total _chans

Too_hot=Too_hot OR Overrange(P)

NEXT P

IF Too._hot THEN

GOBUB Reduce_power

ELSE

CALL Appl y_probe_cal (Frequency)

END IF END IF RETURN

I Amplitude correction,

! Frequency correction,

! ////////////////////////////////////////////////////////////

I Level _eut_out :

This routine will adjust the signal generator

' output to cause the EUT output (tied to (iDvml)

I to -Fall within the limits of Miri_eut and Ma;;_eut.

! All the while within the bounds of Low_dbm to liigh_dbm,

RETURN

I

! ////////////////////////////////////////////////////////////

105
2498

250.2

2504

250i:- 2508

^.s ' n 2512

2514

25 1

6

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2520

2524

2526

2528

253C' 2532

2534

2536

2538

2540

2542

2544

2546

2548

2550

2552

2554

2556

255S

2560

2562

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2566

256B

2570

2572

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2576

2578

2580

2582

2534

2586

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26 1 1.) 2612

2614

2616

;1 _ne't_i nput : 1 This routine .11 adjust the siqna] qenerator

output to cause the corrected net input power

to tall within the limits o-F Min_pwr end ria::_pwr

All the while within the bounds o-f Low__dbiT. to High_dbfri

RETURN

////////////////////////////////////////////////////////////

Ad j u.5t__p ower : ! DISP " INPUT power is too low. Check system (Continue-k5) " QN KEY 5 LABEL "Continue" , Local _prty GOTO Tryitagain

ON KEY LABEL "Reduce Power ", Local _prty GOSUB Reduce_j:iOwer

QN KEY 2 LABEL "Increase Pwr ", Local _prty GOSUB Increa=e_pwr

LOOP

Myself :UN KEY 6 LABEL " dBm= " ^..VAL* ( Dbm ), Local _prty GOTO tiysel-f

END LOOP

Tryi tagai n : OFF KEY

DISP CHR*(12)

RETURN

1 Reduce_power :

!

Dbm=Dbm-l

CALL Set_dbfn (Db.rn , 1 , (gSi g_gen)

IF Print-flag THEN

PRINTER IS Printer

PRINT TIME:? (TIMEDATE) ; ": Step#" ; Steps; " Frea=" ; Frequency;

PRINT RPT:f ("*" , 10) ; " NEW GENERATOR LEVEL =";Db-.

PR INTER IS CRT

END IF RETURN

Incr ease_p wr :

I

Dbm=DbiTi+l

CALL Set_dbm(Dbm, 1 ,@Sig_qen)

IF Print-flag THEN

PRINTER IS Printer

PRINT TINE* (TINEDATE) ; " : Step# '; Steps ; " Freq=" ; Frequency;

PRINT RPT$ ("*", 10) ; " NEW GENERATOR LEVEL =";Dbm

PRINTER IS CRT

END IF

RETURN

////////////////////////////////////////////•//////////.//////

Dual __pi-vir _error : 1 CALL 3et_dbm (- 140 , , @3i g_gen ) I Kill power

IF Printflaq THEN

PRINTER IS Printer

PRINT TINE* (TIMEDATE) ; ": Step# " : St eps : " Freq=" ; Frequency

;

PRINT RPT*("*" , 10) ; " ERROR IN DUAL POWER METER !ll"

PRINTER IS CRT

END IF DISP " ERROR in DUAL POWER METER, correct and 'CONTINUE' " BEEP

106
26 IB

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2626

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2644

2646

2648

2650

2652

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2656

265S

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2672

2674

2676

2678

2630

2682

2684

2686

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2708

27 1 C) 2712

2714

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2718

27 20

2722

2724

2726

2728

2730

2732

2734

2736

PAUSE

CALL Set_dbfri (Dbm, 1 ,©31 g gen)

RETURN

I Re-store poi^er

.

////////////+ PRINT HEADING Ff,3R RAW DA f A*-x **'////////////

/

Print he5din-fc: f '^'alues in order o-f insei-""tion into matri;:.

PRINTER IS Printer

PRINT

SELECT Test_type*

CASE "MODE TUNE REGULAR"

PRINT RPT*("-" , 15) ; "Identifier: ";Run_id*;

PRINT " STEP NUMBER " ; Steps ; RPT* ( "-" , 1 5

)

PRINT "FREQUENCY INC-PWR REFL-PWR "; PRINT " REC-PWR"

PRINT " MHz Watts Watts "; PRINT " Watts"

CASE "MODE TUNE EMISSIONS"

PRINT RPT*("-" , 15) ; "Identi-f ier: ";Run_id:f;

PRINT " STEP NUMBER "; Steps ; RPT* ("-", 15)

PRINT "FREQUENCY REC-PWR " PRINT " MHz Watts

CASE "OTHER (NO STEPS)"

PRINT RPT*("=" ,80)

PRINT "Measurement Identifier: ";Run_id-T

PRINT Measmt_id*

PRINT RPT* (".

" ,80)

PRINT

PRINT "FREQUENCY INC-PWR REFL-PWR "; PRINT " Probe OUTPUT"

PRINT " MHz Watts Watts "; PRINT " Volts"

END SELECT

PRINTER IS CRT

RETURN

/////////////// / ****PR I NT RAW DA TA*^** /////////////////////

/

F'r i ntrawdata: I Rawimaqel: IMAGE 6D.2D,X,#

RawifT,age2: IMAGE #,MD.DDDE,X

PRINTER IS Printer

PRINT USING Rawimagel ; Rawdata ( 1 ,Cclu.mn)

FOR 1=2 TO Total _meters+l

F'RINT USING F.'awi mage2; Rai-jdat a ( I , Col umn ) NEXT I PRINT

IF Total.. Chans;! THEN GOSUB Print_probes

PRINTER IS CRT

RETURN

I-

' ////////////////////////////////////////////////////////// /

/

F'r i nt _pr obes : I PRINT RPT* ( "_" ,80)

PRINT "Amp# Probett A;: i s Zero Output Orng?";

PRINT " Volts/mtr"

Pi mage 1 : IMAGE M3D , 2X , M3D , 3X , A , 3X , 2 (M4D , 2X > , MDD , 2X , M4D. 2D

FOR 1=1 TO Total_chan5

Amp=Pr obe_addr (1,1)

107
2738

2740

2742

2744

2746

2748

2750

2752

2754

2756

2753

2760

2762

2764

2766

2768

2770

2772

2774

2776

2773

2780

2732

2784

2786

2788

2790

2792

2794

2796

2793

2800

2802

2804

2806

2808

28 1 28 1 2

2814

2816

2813

2820

2822

2B24

2326

2828

2830

2B32

2334

2836

2833

284

2342

284 4 2846

2840

2350

2852

2854

2556

FTobe-FTobe__addr (1,2)

SELECT Probe_3ddr ( I ,3)

CASE 1

, ^^ ,1 CAi

CA!

'Y"

A:.* =

5E 2

A;;*=

5E 3

A;;:f="Z"

CASE 4 A;.:*="3"

CASE ELSE

A;;:f="E"

END SELECT

Or q=OverrariqB ( I > Zer=Probe_zerG ( I

)

A_d=Probe_volts ( 1

)

V_m=Rawdat5 (Total _meter-s + PRINT U3IN6 Pimagel ; Amp ,P

NEXT I PFaNT RPT* ("_" ,80)

PRINT

PRINT

RETURN

I //////////// / / / / / / / /****SAVE DATA****/ //////////////////// / /

/

I + 1 , Col u.mn ) robe, A;;:f , Zer , A_d ,Org , V_

S c. V e _d t=i L c< : ! ON ERROR CALL Errortrap

IF Te5t_type*="aTHER (NO STEP

Fi 1 ename-t:=Run_i d$

ELSE

Fi 1 enamef="3".!A'AL$ (Begi ns END IF

Fi I E'nan"ie-f--Fi 1 ename$5<0utdi s !;::$ Fi lesize=INT ( ( (Total _chan5+To

CREATE BDAT Fi 1 ename* , Fi 1 esi

z

ASSIGN @Datapath TO Filename*

OUTPUT @Datapath;Rawdata (*)

ASSIGN (^Datapath TO * PRINTER IS Printer

IF Test __type$=" OTHER (NO STEP

PRINT TIME* (TIMEDATE) ; " . ELSE

F i 1 en ame-f= " S " ?.:VAL* ( Beg ins

PRINT TIME* (TIMEDATE) ; '

. .

S) " THEN

tep)?<"_"?.:VAL* (Endstep)

tal_meter5+l ) *Fi Ie20step5*3) /256' +2

e , 256

i) " THEN

... DATA STORED ON FIL

END

OFF

PRINT

IFERROR

PRINTER IS

RETURN

Begi nstep

;

CRT

TO " ; En

tep)?/"_"?<VAL* (Endstep)

DATA FOR STEP

dstep;" STORED ON FILE

E "

; Fi 1 enaiTie*

S

Fi 1 ename*

! //////////////////**** SAVE CONFIGURE ****//////////////////

Save_cori-F i gure: ! ON ERROR CALL Errortrap

Fi lenamef=" CONFIGURE"

Fi 1 ename*=Fi 1 ename*?-Ontdi sk*

CREATE BDAT Fi 1 ename* , 1 6 , 256

ASSIGN ^Datapath TO Filename*

OUTPUT ©Datapath; Ru,n_id*

108
2S53 OUrPUT ^Datapath; Me35mt_id*

2B60 OUTPUT ©Datspath; Ti me datet2862 OUTPUT ©Datapath ; F-start , Fstop , Fstep

2864 IF Test_ tvpe*=-"OTHER (tiD STEPS)" THEN

28a6 OUTPUT (2Datapath;l

2B63 ELSE

2370 OUTPUT ^Datapath ; Total _£tepB

2872 END IF 2374 OUTPUT ©Datapath ; Tot al .meters

2376 OUTPUT ©Datapath ; Total _chans

2373 OUTPUT ©Datapath ; Probc_addr (* > 2830 OUTPUT ©Cat ipath ; Meter__de-f ns* (*)

2832 OUTPUT ©Datapath ; Fi 1 e20steps

2834 ASSIGN ©Datapath TO * 2336 OFF ERROR

2833 PRINTER IS CRT

2890 PRINT TIME*(TIMEDATE) ; " CONFIGURE -file -for ";Run_id$;" SAVED."

2392 RETURN

2894 I 2396 I ////////.'///////////////////////////////////////////////////

2393 ' 2900 Pri nt_vi tals: ! 2902 PRINTER IS Printer

2904 PRINT RPT*("_",SO)

2906 PRINT "THIS DATA SET IS IDENTIFIED AS: ";Run_idt2908 PRINT "MEASUREMENT date: " ; Ti me_datet2910 PRINT RPT*("-",BO)

2912 PRINT Mea5mt_id*

2914 PRINT RPT*i"-",30)

2916 PRINT "FREQUENCIES ";Fst5rt;" TO "

2918 PRINT Fstcp;" STEP ";Fstep;" MHz,"

2920 PRINT "THE TUNER STEPPED "; Total _steps; " increments."

2922 PRINT Total __meters; " PWR METERS and DVMs , along with "; Total _char,5;

2924 PRINT " channels of the NBS multiprobe system."

2926 PRINT

2928 PRirjT "The measured DATA are de-fined as -follows:"

2930 PR I NT RPT* ( " -

"

, 30

2932 PRINT "Data slot # Description";

2934 PRINT TAB ( 40 ) ; " Data slot # Description"

2936 J = INT ( ( (Total _chan3 + Total_meters) /2)+l

2933 IF J-::;>( <Total_chan5H-Total_meters) /2) -t-1 THEN J=J-t-l 294 1=1

2942 K=J ! J is starting point of second column.

2944 REPEAT

2946 PRINT I;": "

; Mete!'_def nsf ( 1 ) ; 2943 IF K<=Total_chans-t-Total._meters THEN

2950 PR I NT T AB ( 40 ) ; K ; " : "

; Meter _d e+ n s:r ( K

)

2952 ELSE

2954 PRINT

2956 END IF 2953 1^1+

2960 K=I>1

2962 UNTIL I >=

2964 PRINT RPTt("-",SO)

2966 PRINT USING "2/"

2960 PRINTER IS CRT

2970 RETURN

2972 ' 2974 ' ////////////////////////////////////////////////////////////

2976 !

109
297 S

29SO

29S2

2934

2986

2983

2990

2992

2994

2996

2998

300'J

3002

3004

3006

3008

30 1 30 1

2

3014

30 1

6

3013

3020

3024

3026

3023

3030

3032

3034

3036

303S

3040

3042

3044

3046

3048

3050

3052

3054

3056

3058

3060

3062

3064

3066

3068

30'70 3072

3074

3076

3073

3080

3082

3084

3086

3038

3090

3092

3094

3096

END

SUB tieasur e_/TienLi

MeasLir e_ menu

Or i q i n a 1 : 5 May 1984

Revision: 24 Jan 1986

This routine will facilitate setting up the

measurement by providing MENU access to the

parameters.

COM /Parameters/ REAL Fstart , Fstop , Fstep

COM /Parameters/ REAL Mi n_eut , MaK_eu.t , Mi n_pwr , Max _pwr , Ti me_eat

COM /Parameters/ INTEGER Low_dbm , Hi gh_dbm , Step_dbm

COM /Parameters/ INTEGER Search_eut , Search_pwr , Re_run

COM /Parameters/ INTEGER Beqi n^step , Total _Eteps , 7 otal _(TieterE

COM /Parameters/ F<un_i d* , Measmt_i d* , Time_date^

COM /Parameters/ Meter _de-fns:l^ ( ) , Opere.tor_name:|' , Te5t_type$

COM /Parameters/ Coupl er_i d* , Generator_i d*

I COM /Files/ Sourcedi sk* , Outdi s k* , Fi 1 ename*

COM /Bugs/ INTEGER Bug 1 , Bug2 , Bug3 , Pr i nter

COM /Interrupts/ INTEGER Intr_prty

DIM Test*: 160]

INTEGER Local _prty, I

, Asci i _ num , Interrupted

Local _prty=Intr_jDrty

DISP CHR*(129)

IF Printer =701 THEN

ON TIMEOUT 7,. 5 GOSUB Printerdead

PRINT

OFF TIMEOUT

END IF

IF Bugl THEN

PRINT TIME* (TIMEDATE) sRPTf ("*" , 10) ; " ENTER Mea5ure_menu"

END IF CALL Wipe_.clean I Clear the CRT.

PRINTER 13 CRT

GOSUB Write_backQnd

IF NOT Re_run THEN

GOSUB Start_up_values

ELSE

GOSUF: Fill _in_ values

END IF

! Format menu. area.

I Initial values

I Put initial values in menu

! Put current values in menu

I

lMah:e any changes or corrections.

I GOSUB Define _keys

PR 1 NT I AB X Y (56,3) ; DATE* ( T I MEDATE

)

LOOP

IF Interrupted THEN GOSUB Def i ne__.keys

ON KEY 5 LABEL "EXIT -RESET ", Local _prty GOTO E;cit_sub

ON KEY 15,LocaI_prty GOSUB St ar t _up__val ues PRINT TABXY(69,3) ; TIME* ( T I MEDATE

)

END LOOP

E>cit sub: I

110
297S

2980

2982

2984

2986

2983

2990

2992

2994

2996

2998

3>000

3002

3004

3006

3008

30 1 30 1 2

3014

3016

30 1 a 3020

3022

3024

3026

3028

3030

3032

3034

3036

3038

3040

3042

3044

3046

3048

3050

3052

3054

3056

3058

3060

3062

3064

3066

3068

3070

3072

3074

3076

3078

3080

3082

3084

3086

3038

3090

3092

3094

3096

END

******************** **->^*** ************************* *^^

SUB MeasL;re_meriLi

Measure, menu: !

' r i q i n a 1

5 M a v 1984

! Revision: 24 Jan 1986

I This routine will facilitate:;' setting up thie

! measurement by providing NE:NU access to the

! parameters.

COM /Parameters/ REAL Fstart , Fstop , Fstep

COM / F' a r a. (n e t e r s / REAL Mi ri _ e u t , ft a ; ; _ e i j. t , M i n _p w r , M a

;

'. p w r

- , T i i n e _b COM /Parameters/ INTEGER Low dbm,High dbm.Step _db,T, COM /F'arameters/ INTEGER Search__eLit , Search _pwr , fSe run

C M / F' a r a m e t er s / 1 N7 E GE R Begin ^ s t ep , T c t a 1 _ s t e p s , 1 o t a 1 _ jti e t e r s COM /F'arameters/ F;un_i &H , Measmt_i d$ , Ti me_ datef

C M / F' a r a ni et er s / Meter _ _d e f n s * ( * ) ,0 f) er a t o r _ n a m e 4 , T e s t _ t y p e f

•

COM /F'arameters/ Coup 1 er _i df , Generator _._i d-TI COM /Fi 1 es/ Sourcedi sk* , Outdi skt- , Fi 1 ename$

COM /Bugs/ INTEGER Bug 1 , Bug2 , Bug3 , Pr i nter

COM /Interrupts/ INTEGER Intr_.prty

DIM Test *C 160]

INTEGER Local_prty, 1 , Asci i_ num, Interrupted

Local __prty=Intr_jDrty

DISP CHR*(129)

IIF Printer =701 TFIEN ON TIMEOUT 7,. 5 GOSUB Printerdead

PRINT

OFF TIMEOUT

END IF

IIF Buql THEN

PRINT TIME* (TIMEDATE) ; RPT* ( "*" , 10) ;; " ENTER Measure_jTienu " END IF

CALL Wipe_clean ! Clear the CRT.

PRINTER IS CRT

GOSUB Write__taackQnd

IF NOT Re_run THEN

GO S U B Start _li p _v a 1 u. e s

! Format menti area.

I Initial values

) Put initial value in mer'iU. ELSE

GOSUB Fill __ i n _. va 1 ues END IF

I F'ut current values in meriu

IMal:e any changes or corrections.

G S U B D e f i n e _.k e y s PR I NT TAB X Y ( 56 , 3 ) ; DATE* < T 1 MEDATE

)

LOOP

IF Interrupted THEN GOSUB De-f i ne_ .keys

ON KEY 5 LABEL "EXIT -RESET ", Local _prty GOTO Exit, sub

ON KEY 15, Local prty GOSUB Start_ up...val ues PRINT TABXY(69,3) ;TIME* (TIMEDATE)

END LOOP

E;;it sub: !

Ill
OFF" KEY

DI3P CHR:t^(12)

Time _datet=1 IMtt (TIMEDA TE) .'r<" , "?-:DtiTE.t (T IMEDi'iTE)

PRINTER IS Printer

IF Printer^yOl THEN DUMP ALPHA

IF Buql THEN

PIvlNT TIMEt iTIMEDATE) ;RPTf C'-*^" , 10) ; " EXIT Mea5ure_m£nu"

END IF CALL Wipe_clean

PRINTER IS CRT

SUBEXIT

I

I /////////////////////////// / / ///////////////////////////////

309£>

3100

102

3104

3 1 06

ill 03

3110

112

3114

116

3118

120

3122

3124

126

3128

3 1 30

>132

3134

3 1 36

138

3140

3142

3144

3146

3148

3150

152

3154

3 1 56

3153

160

3162

3164

3166

5160

3170

3172

:i74

176

;i73 ! 313^> Start _up_val Lies: I Define the initial values -for all parameters.

Re run=l

! Frequency range in MHz.

Def i ne__key5: I OFF KEY

Interru

DISP RP

DISP " ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

ON KEY

IF Test

ON

ON

END IF ON KEY

RETURN

pted=0

T*("<" , 15) ; " SELECT PAR

(•shift key) ":RPT:3r(">"

LABEL "TEST ID -TYPE",L

10,L.ocal_prty GOSUB Change

1 LABEL "FREQs -SIG GEN",L

1 1 ,Local_jDrty GOSUB Change

2 LABEL "INPUT MIN MAX",L

12, Local _prty GOSUB Change

3 LABEL "LEVEL -SEARCH",

L

13,Lccal_prtv GOSUB Change

4 LABEL "EUT MIN •MAX"^L

14, Local jDrty GOSUB Change

6 LABEL "DATE •NAME",L

16,Local_prty GOSUB Enter_

7 LABEL "Response Time",Lo

_type*<>"OTHER (NO STEPS)"

KEY 8 LABEL "TUNER -BEG I KEY 18,Local _prty GOSUB Ch

AMETER TO CHANGE ";

, 15)

ocal_prty GOSUB Change_eLit i d

_type

ocal_prty GOSUB Change_-f reqs

1 evel

s

ocal_prty GOSUB Change__pwr_mi n _pwr__ma;;

ocal_prty GDSUEi Change_SBarch_p

search _e ocal_prty GOSUE: Change_eL(t_mi n eut_ma;-;

ocal_prty GOSUB Cal 1 _t i me__date name

cal_prt^/ GOSUB Change_re5ponse

THEN

t^l" , Local _prty GOSUB Change_tLiner

ange_beqi nstp

9 LABEL "DISK DR I VE "

, Local _pr t y GOSUB Change _di skdri

v

////////////////////////////////////////////////////////////

5132

>184

3186

3188

3190

3192

194

3196

3198

;.2C)0 >202

>204

'206

'.203

'•2 1 >212

F214

!;216

Fstart=100

Fstop=1000

Fstep=50

Low_dbm=--40

Hiqh_ dbrri=-10

Step.,dbm=l

Sear ch_eut=0

Search pwr=0

Min_eut-1 . OE6

Ma;;_eut = 10.

Min_pwr = l . OE-6

Ma;c_.pwr = 10.

Ti (Tie_eut"0.

Beg 1 n_step=

1

Total _steps=200

Signal generator level in dBm.

0= DO NOT auto search -for EUT response

1= DO

0- DO NOT auto level the Net Input poi-ier.

1= DO

Minimum output of EUT in volts.

Maximum output of EUT i ri volts.

Minimum net input power in watts.

Maximum net input powei^ in watts.

Time for EUT to respond after field is set.

An integer division of 3200

112
321G

3224

TL?st type*=="r-lGDE TUNE REGULAR" 'or "MODE TUME EMI3SI0IJS'

' or "OTHER (NO STEF'S) "

Fv'un _ I d'f = " Run __1 " Operator _ri£ifTief=''Gal eii f-^oepl e"

fieasmt _ i d'4-~"£val Liate tUa SL-.sceptab i 1 i ty of a device"

Mea5iTrt_ i d^f-Measmt _i d$S<'' in the NBS Reverberating Chamber.

CcLipl er _i d*-"HP 773D"

Generator idf="HF'' 8660A"

3233

3240

3242

3244

3246

3248

3250

32tj2

3254

3256

3253

3260

3262

3264

3266

3268

3270

3272

3274

3276

3278

3280

3232

3234

3236

3288

3290

7^29'^' 3294

3296

3293

3300

3302

3304

3306

3308

3310

3312

3314

3316

33 1

8

3320

3323

3330

3336

G03LIE; Fill

RETURN

in value; I F'ut initial values in menu

! ////////////////////////////////////////////////////////////

Fi 1 1 _i n_val ues : !

I GOSUB Change_eutid I Fill in the values

GOSUB Print_type

GOSUB Print_-freqs

GOSUB Print_gen_.level

GOSUB Print_beqinstp

GOSUB Print_tuner

GOSUB F'rint_naiT(e

GOSUB F'rint_=earch_p

GOSUE! Pr i rit_search_e

GOSUB Pr i nt_eut __mi n GOSUB Print_eut_ma;-!

GOSUB Pr i nt_pwr_ mi

n

GOSUB Pr i nt_p wr _ma;; GOSUB Print_wait

GOSUB Pr 1 nt_di sl::dr i ve RETURN

I

! ////////////////////////////////////////////////////////////

Wr i te_backgnd Format menu Sirea.

PRINT CHR*(129)

PRINT TABXY( 16,1);

PRINT TABXYd ,3) ; " PRINT TABXY(23,3)

;

PRINT TABXY(41 ,3)

MEASUREMENT PARAMETERS

TEST ID: " TYPE: " DATE / TIME: "

PRINT CHR*(132)

;

PRINT TABXY (1 ,5) ;RPT:J-- ( " ",160)

PRINT CHR*( 129)

;

PRINT TABXY ( 1,3); " FREQUENCY (MHz

)

PR 1 NT TAB X Y ( 1 , 9 ) ; " LOW : " PR 1 N

T

T f (B X Y ( 1 , 1 T' ) ; " HI GH : " PRINT TABXY (1,11);" STEP: " PRINT TABXy (21 ,8) ; " GENERATOR (dBm)

PRINI TABXy (41 ,3)

;

PRINT TABXY (41,9);

PRINT TABXY (41 , lH)) PRINT TABX/(41,11)

PRINT TABXY (65,3)

;

PRINT TABXY (65, 1 1 ) PRINT CHRt (123)

;

PRINT TABXY (62,9)

;

NET INPUT POWER (W) M I N : " MAX: "

' LEVEL INPUT? " EOT RESPONSE

' SEARCH? "

113
333a

;40 42

34 4 ?46

T.43

;.54

'53

;60

3362

3364

5366

J363

3374

3376

337B

3330

382

334

3336

;38a

>390

3394

3396

3398

3400

3402

3404

3406

3403

3410

3412

3414

3416

5418

5420

5422

5424

5426

3428

5430

5432

5434

3436

5438

5440

5442

3444

3446

3443

3450

3452

5454

3456

PF-IM1 TABXY (62, 10^ ; PRINT CHR* (129)

PRINT TABXY (1,13);"

PRINT TABXY (41 , 13> ; PRlhiT TABXY (41,15;;

PRINT 1 ABXY ; 1 , 15:> ; " PRINT TABXY (29, 15)

PR IN I TABXy (1.17);"

PRINT TABXY (41,17);

PRINT CHRir(123)

RETURN

ESTIMATE EUT RESPONSE TIME

' seconds. "

; RPT-t- ( " ",

' COUPLER/SID GEN: "; BEGIN TUNER POSITION

' END " OPERATOR: ";

' OUTPUT DISK DRIVE: '

30)

! / / / / ////////////////////////////////////// / /' / '///// / / / / / / / / /

I Printerde-ad: DISP "NO PRINTER et HPIB address 701 II"; DISP " Please? ccrrect situation and hit 'CONTINUE " BEEP

PAUSE

RETURN

I

I ////////////////////////////////////////////////////////////

I Cal 1 _t i me__date: Interrupted=l

CALL TiiTie_.date

RETURN

1

' ////////////////////////////////////////////////////////////

Change__eut_iTia;; : IntE-rrLipted= 1 IF Te5t_type*-="MaDE TUNE EMISSIONS" THEN RETURN

DISP " ENTER the UPPER LIMIT -for the EUT RESPONSE (your urats) "; INPUT Ma:;_eut

IF MaK_eu.t<Min_eut THEN

Mi n_eLit=Ma:: _..eLit G03UB Ft i nt__eut_min

END IF FTi nt_eu.t_ma;; : I PRINT TABXY (66, 10)

IF Test_typet="MODE TUNE EMISSIONS" THEN

PRINT USING "9A";" Not used"

ELSE

PRINT USING "MD.2DE";Ma;(_eut

END IF RETURN

I

! //////////////////////////////////////////////////// / / / / / / /

/

ChanqE_eut _friin: 1 nterrupt ed~l

IF NOT Search eut OR Test __type-r=" MODE TUNE EMISSIONS" THEN RETURN

DISP " ENTER the LOWER LIMIT ^or the EUT RESPONSE (your units) "

INPUT Min_eut

IF Min__eut>Ma;:_eu.t THEN Mi n_eut=Ma;; _eut

F-'r i r\t _eut n"!i n :

' PRINT TABXY (66,9)

IF NOT Search __eut OR Test _type*=" MODE TUNE EMISSIONS" THEN

PRINT USING "9A";" Not used"

ELSE

PRINT USING "MD. 2DE";Min_eut

END IF RET URN

114

i
3453 ! 346'.) ! ///'////////// / / / / / / / / ////// / / //////// / / ./ / /////////// / / / / / / / / 3462 I 3464 Chianqe_ pwt' _ ma.;; : InterruptBd=l

3466 IF NOT Search ..pwr OR Te3t_t vpe*=--"hODE lUtlE EMISSIONS" THEN R'ETURrJ 3468 DI3P " ENTER the Ma;; i mum NET Input Power "; 3470 INPUT Ma;;_pwr

3472 IF Ma;;_pwr<0. THEN Ma;; _p.wr=0.

34 74 IF Ma;;_pwr<Min_pwr THEN

3476 Mi n_.pwr=MaK_pwr

347S GOSUB Pr i nt_pwr_mi

n

3480 END IF 3482 Pri nt_pwr_maK :

!

3434 PRINT TABXY (50 , 10)

;

3486 IF NOT Search_pwr OR TeEt_typet="MDDE TUNE EMISSIONS" THEN

3438 PRINT USING "9A";" Not used"

3490 ELSE

3492 PRINT USING "MD. 2DE" ; Ma;;_pwr

3494 END IF 3496 RETURN

3498 ! 3500 1 ////////////////////////////////////////////////////////////

3502 I 3504 Changc_j:'wr_mi n : Interr upted1

3506 IF Test_type4;-"M0DE TUNE EMISSIONS" THEN RETURN

3508 DI3P " ENTER the Minimum NET Input Power "; 3510 INPUT Min_pwr

3512 IF Min_jDwr<0. THEN Min_jDwr=0.

3514 IF Mi n _pwr :>MaK_pwr THEN Mi n_pwr=Ma;;_pwr

3516 Pri nt_pwr_mi n :

1

3518 PRINT TABXY (50,9);

3520 IF Test_type*="MODE TUNE EMISEICNS" THEN

3522 PRINT USING "9A";" Not used"

3524 ELSE

3526 PRINT USING "MD. 2DE" ; Mi n_pwr

3523 END IF 3530 RETURN

3532 ! 3534 ! ////////////////////////////////////////////////////////////

3536 ! 3538 Change_search_p :

!

3540 IF Search_pwr=0 AND Search_eut=0 THEN

3542 Search_pwr=l

3544 ELSE

3546 Search_pwr=0

3543 END IF 3550 GOSUB Pr i nt_gen_ 1 evel

3552 GOSUB Pr i rit_pwr_iTia;;

3554 F-'rint search _p: ! 3556 PRINT TABX / ( 56 , 1 1 ) ; 3558 IF Test _type*=--" MODE TUNE EMISSIONS" THEN

3560 PRINT "OFF"

3562 ELSE

3564 IF Search._pwr THEN

3566 PRINT "ON " 3568 ELSE

3570 PRINT "OFF"

3572 END IF 3574 END IF 3576 RETURN

115
'.578 5580

55 S 4 3536

5588

J 5 90

5592

3594

?596

3593

5600

3602

3604

3606

3608

36 i 3612

3614

3616

3613

3620

3622

3624

3626

3623

3630

3632

3634

;.636 3633

3640

3642

3644

3646

:.64S 3650

3652

3654

3656

3658

3660

3662

5664

3666

3663

3670

3672

3674

3676

3678

3680

3682

3684

3636

3688

3690

3692

3694

3696

///// ' / /' / / / / / / / / / / / / / / //////////////////////// / / / / / / / / / Change search e-: I IF Search _c?ut=-0 Al'-'D Scarch__pwr=0 THEM

Search eul^l

ELSE

Search eut=0

END IF GDSlJB F'r i rit__q(?n_l e\ el

3O S U h P r 1 n t __e Li t _ m 1 n

F'r i nt_ sear ch e: ' PRINT TABXV (75, 11);

IF Te5t_type*=-"MaDE TUNE EMISSIONS" THEN

PRINT "OFF"

ELSE

IF Search_eu.t THEN

PRINT "ON " ELSE

PRINT "OFF"

END IF END IF RETURN

///////////////////////////////////////////////////////// / / / Uhanqetype:

!

Interru.pted = OFF KEY

SELECT MEASUREMENT TYPE.

LABEL "Source = ANT", Local

LABEL "Source = EUT", Local

LABEL "NO TUNER STP", Local

DISP " ON KEY

ON KEY

QN KEY

LOOP

END LOOP

Source_ant: ! Regular MODE TUNED TESTS wit

Te3t_type*="M0DE TUNE REGULAR"

Measmt__idt="EvaI uate the suBceptabi

MGa3mt_..id*=Measmt_id$?<" in the NBS

GOSUB Print__eutid

GOTO New_type

Source _eut: I Emissions using MODE TUNED

Test_.type*="MODE TUNE EMISSIONS"

Measfrit_i dt= "Measure the radiated em Measmt id*=MGa5ait__id*?;" in the NBS

GOSUB Print_eutid

GOTO New_typa

Notunerstep: ' Other measurements that req

Test. typet="OTHER (NO STEPS)"

Measmt_ i dt-"Measure the response oT

_prty+l GOTO Source_ant

_prty+l GOTO Source_eut

_prty+l GOTO Notunerstep

h transmitting antenna

1 i ty o-F a devi ce"

Reverberating Chamber.

sequence, EUT is source

issions o-f a device"

Reverber^tt i nq Chamber.'

Measmt _i d*=Mea 3.nt__i dt?

GOSUB F-rint_eutid

New__type: OFF KEY

' Update all the menu GOSUB Print_gen_l evel

GOSUB Print_begi nstp

GOSUB Print._tuner

GOSUB Print_search_e

GOSUB F'r i nt_search_p

GOSUB Print_qcn_id

in the NDS

uire no TUNER step pi rig

a device to a -field"

1 . 2 meter TEM CELL.

iteins af-fected by TYFE change.

116
3693 GQSUD FT i nt _pwr_i-ni n 3700 GOEUB Pr i nt_pwr_iTra;'

3702 GOSUB Pr i nt._eut_f7ii n

370-^ GOSLIb Pr-int_eLit jTia;! 3706 F'rint_type: I 3708 PR I NT CHR* (129) ; 37 1 PR I NT TABX Y ( 45 , 1 ^ ; 3712 SELECT Te5t_type*

3714 CASE "MCiDE TUNE REGULAR" , "MODE TUNE EMISSIONS"

3716 PRINT "MODE TUNED TESTS";

3718 CASE "OTHER (NO STEPS)"

3720 PRINT "TEM CELL TESTS "; 3722 CASE ELSE

3724 PRINT "T???????????"^???" ; 3726 END SELECT

3725 PRINT CHR*(128);

3730 PRINT T AB X Y ( 3 1

, 3 )

;

3732 SELECT Te5t_type*

3734 CASE "MODE TUNE REGULAR"

3736 PRINT "REGULAR " 3738 CASE "MODE TUNE EMISSIONS"

3740 PRINT "EMISSIONS"

3742 CASE "OTHER (NO STEPS)

3744 PRINT "OTHER

3746 CASE ELSE

3748 PRINT "?????????"

3750 END SELECT

3752 RETURN

3754 ! 3756 ! ////////////////////////////////////////////////////////////

3758 ' 3760 Change_begi n = tp : Iriterrupted = l 3762 IF fe3t_type*="0THER (NO STEPS)" THEN GOTO Pr i nt_beg] n=tp

3764 DISP " ENTER THE BEGINNING TUNER STEP NUMBER "; 3766 INPUT BGqin_step

3768 IP Beqi n_step >Total _5teps THEN Begi n_5tep=TotaI _Bteps

3770 Print_beqi nstp :

I

3772 PRINT TABXY (24 , 15)

;

3774 IF TeBt_type*<>"OTHER (NO STEPS)" THEN

3776 PRINT USING " 4D" ; Beg i n_step

3778 ELSE

3780 PRINT USING "4A";"N/A " 3782 END IF 3784 RETURN

3786 ! 3788 ! //////////////////////////////////////////'//////////////////

3790 ! 3792 Change_tLiner : ! 3794 IF Test_type*="OTHER (NO STEPS)" THEN GOTO Print_tuner

3796 SELECT Total _steps

3798 CASE 3200

3300 Total __5tep 5=1 00

3802 CASE 1600'

3304 Total _5teps=3200

3806 CASE 800

3803 Total _step5= 1600

3810 CASE 400

3812 Total _.steps=800

3814 CASE 200

3816 Total_5teps=400

117
-.818 CASE 100

.'820 Total _si.eps =200

'822 CASE ELBE

J324 Total _5tep5--=400

'826 END SELECT

3823 Pr i nt_tuner :

:.83(.> FR I NT TAB X Y (35,15);

;a32 IF Test_type-r-.> "OTHER (NO STEPS)" THEN

5834 PRINT USING "4D" ; Total _step5

r.836 ELSE

5838 PRINT USING "4A";"N/A " :.a40 END IF 5842 IF Beqin_5tep>Total__5tep5 THEN

5344 Ijeqi n__step = Total _5teps

5S46 GOSUB Pr i nt_beqi nstp

5843 END IF 5850 RETURN

5852 ! 5854 ! ////////////////////////////////////////////////////////////

5856 ! 5858 Change_eu.ti d: InterrLipted=l

5360 ' DI3P " ENTER the TEST ID+t (LEGAL FILE NAME) "; 5862 OUTPUT 2 USING "K , #" ; Run_i d*

5864 L INPUT Test*

5866 IF LEN(Test*)=0 THEN Change_eut i

5863 IF LEN (Tester) >10 THEN

5870 BEEP

5872 DISP " ERROR in NAME ENTRV —100 MANY CHARACTERS, TRY AGAIN. " 5874 WAIT 1.3

5876 OUTPUT 2 USING "K , tt " ; F i 1 ename*

5878 GOTO Change _eut id

5880 END IF 5882 FOR 1=1 TO LEN(Test*)

5884 Asci i_num=NUM(Test*[ I :

)

5836 SELECT Ascii...num

5888 CASE 65 TO 90,95,97 TO 122,48 TO 57

5890 ! All owed characters

5892 CASE ELSE

5894 BEEP

5896 DISP "ERROR in NAME ENTRY —ILLEGAL CHARACTERS, TRY AGAIN."

5898 WAIT 1.3

5900 GOTO Chanqe_eutid

5902 END SELECT

5904 NEXT I 5906 Run _i d*^ = Test*

5908 ! 5910 DISP " DESCRIPTION o-f the EUT and PURPOSE -for test?? (<2 lines) "; 5912 OUTPUT 2 USING "K , tt" ; Measmt_i d

'914 L INPUT Measmt_id*

5916 Print ..eutid: ' 5913 PRINl" TABXY( 12,3) ;RPT*(" ",10)

5920 PRINT TAOXY( 12,3) ;RLin_id-t:

5922 PRINT CHR*(132)

5924 PRirJT TABXYd ,5) ;RPTr (" ",160)

5926 PRINT T ABX Y ( 1

, 5 )

; Measmt_i dt

5928 PR I N T CHR* (123) ; 5930 RETURN

5932 ' 5934 I ////////////////////////////////////////////////////////////

5936 !

118
3938 Eriter_.f req_er: I 3940 DISF' " ERROr^ in numeric entry or ILLEbAL -.alue. " 3942 BEEF' 3944 WAIT 1.3

3946 Change__freqs : Interrupted-l

3948 DISP " ENTER Start, Stop, Step -frequencies (flHz). "; 3950 DISP' "CRanqes: 1-30, 30-2000, 2000-13000:";

3952 LINF-UT Test*

3954 ON ERROR GO FO Enter_-f r eq _er 3956 Fst art =VAL (Test*)

3953 Fstop=VAL ( Test* CPOS (Test*, "

, ')h-1])

3960 Te5t*=Test*CP0S(Te3t*, "

, " ) + 1 ,LEN(TeBt*)

3962 F5tep=VAL(Te5t*CPasn"est*, "

, ">-t-i:)

3964 OFF ERROR

3966 IF F5tGp<Fstart THEN GOTO Enter_-f req_er

3968 F5tart=MAX (MIN (Fstart , 18000) , 1

)

3970 Fstop=MAX (MIN(F5top, ISOOO) , 1)

3972 Fstep=MAX (MIN(Fstep, 18000) , .01)

3974 SELECT F5tart+ (Fstop-Fstart ) /2 IMid point in the range o-f -freq.

3976 CASE <=30 ! Set limits to 1-30 range

3978 IF F5top>30 THEN Fstop=30

3980 Generator_icl*="HP_8660A"

3982 Coup 1 er _i d*= "CH._1 30_4 " 3984 CASE O2000 ! Set limits to 30-2000 range

3986 IF F5tart<30 THEN Fstart=30

3933 IF F5top>2000 THEN F5top-2000

3990 Coupler_id*="HP...773D"

3992 Gen er at or _id*="HP__8660A"

3994 CASE >=2000 ! Set limits to 2000-18000 range

3996 IF Fstart<2000 THEN Fstart=2000

3993 Coupler_id*="HP_l 3 692D"

4000 Generator_id*="HP_3672A"

4002 END SELECT

4004 Print_-freq5: ' 4006 PRINT TABXV(9,9);

4008 PRINT USING "5D. 2D" ; Fstart

40 1 PR INT T AB X Y ( 9 , 1 (J ) ; 4012 PRINT USING "5D . 2D" ; Fstop

4014 PRINT TABXY(9,11);

4016 PRINT USING "5D. 2D" ; Fstep

4018 F'rint__gen _id: I 4020 PRINT TABXY(59, 15) ;RPT*(" ",21);

4022 IF Test _type*=" MODE TUNE EMISSIONS" THEN

4024 PRINT TABXY(59, 15) ; "Not used"

4026 ELSE

4028 PRINT TABXY (59, 15) ; Coupler_id*; "/"; Generator _i d*

4030 END IF 4032 RETURN

4034 I 4036 I ////////////////////////////////////////////////////////////

4033 • 4040 Change levels: Interrupted--!

4042 IF Test..type*="MODE TUNE EMISSIONS" THEN RETURN

4044 _ IF Search_eut OR Search. pwr THEN

4046 DISP " ENTER the LOW, HIGH, STEP Signal generator LEVEL (dDrri) "; 4048 DISP " ...integers only I "; 4050 INF'UT Low_dbm,High_dbm,Step_dbm

4052 IF Low_dbm>Hi gh_dbm THEN Low__dbfTi=Hi gh__dbm I capped by high_dbm

4054 IF Step_dbm<l THEN Step_dbm=l

4056 ELSE

119
4058

40.i.C» 4062

4064

4066

406B

407(I> 4072

4074

4076

4078

4080

4032

4034

4036

4033

4090

4092

4094

4096

4098

4 1 00

4102

4104

4 1 06

4103

4110

4112

4114

4116

4113

4 1 20

4122

4124

4126

4128

4130

4132

4134

4 1 36

4 1 38

4140

4142

4144

4146

4148

4150

4152

4154

4156

4153

4160

4162

4164

4166

4168

4 1 70

4172

4174

4176

Print

DIEF " ENTER Siqnal generator

DISP " ...integers only! "; irJPUl Lowdbm

IF Hi gh_ dbin<Low_dbm

END IF _qen _ 1 eve I : I 'print CHR:r(129) ; SELECT Te5t__.type*

LEVEL (dB.T,)

THEN Hiqh _dbm=LDW dbrn capped by lowdbm

CASE "MODE TUNE REGULAR "

, "OTHER (NO STEPS)

IF Search e^jt OR Se= arch jDwr THEN

PRINT TABXY(21

,

9);"' LOW: " PRINT TABXY (21

,

10);" HIGH: " PRINT TABXY (21

,

11);" STEP: " ELSE

PRINT TABXY (21

,

9) ; " FIXED: " PRINT TABXY (21, 10);"

PRINT TABXY (21

,

11);"

END IF CASE "MODE TUNE EMISSIONS"

PRINT TABXY (21 ,9) ;

NOT " PRINT TABXY (21 , 10)

USED " PRINT TABXY (21 ,11); " .... " CASE ELSE

PRINT TABXY (21 ,9) ;

ERROR " PRINT TABXY (21 , 10)

"DETECTED"

PRINT TABXY (21 , 11)

"IN TYPE!

END SELECT

PRINT CHR*(12a)

PRINT TABXY (30, 9)

PRINT USING "4A";

PRINT TABXY (30, 10)

PRINT USINQ "4A";

PRINT TABXY (30, 11)

PRINT USING "4A";

PRINT TABXY C

PRINT USING

PRINT TABXY

C

PRINT USING

END IF END IF RETURN

IF Test._type*<.>"riODE TUNE EMISSIONS" THEN

PRINT TABXY (30,9)

PRINT USING "4D";Low_dbm

IF Search_eut OR Search_pwr THEN

•0 ,10) ; '4D";High_dbm

>0 ,11);

"4D" ;Step_dbm

////////////////////////////////////////////////////////////

Change. response: I nt err up t ed=

DISP " ENTER time for EUT to respond a-fter field is set. (seconds)

INPUT Time__eut

Pr i nt wai t : ! ">R I N r TABXY ( 30 ,13);

IF Time_eut<9999 THEN

PRINT USING "X,5D.3D";Time_eut

ELSE

PRINT USING "MD. 3DE"; Time_eut

END IF RETURN

120
4178

4130

4182

4134

4186

4183

4190

4192

4194

4196

4193

4200

4202

4204

4206

4208

42 1 4212

4214

4216

4218

4220

4222

4224

4226

4228

4230

4234

4236

4233

4240

4242

4244

4246

4248

4250

4252

4254

4256

4253

! ////////////////////////////////////////////////////////////

Enter_name: Iriterrupted=l

DISP " PLEASE TYPE IN YOUR NAME "; L INPUT Test*

Operator_riame*=Test*II 1 , 23 J Pr i nt_narrie: I PRINT TABXY(13, 17) ;RPT*( " ",28);

PRINT TABXV ( 13, 17) ; Operator_na(De-f

RETURN

////////////////////////////////////////////////////////////

Change_ di skdri v:

OFF KEY

Iriterrupted=l

DISP " SELECT DISK DRIVE -for DATA OUTPUT. " ON KEY LABEL "LEFT Internal ", Local _prty+l GOTO Lef t_i nternal

ON KEY 2 LABEL "9133 HARD DISK" , Local _prty+l GOTO Hard9133

ON KEY 4 LABEL "RIGHT Internal ", Local _prty+-l GOTO Ri ght__i nternal

ON KEY 7 LABEL "9133 -f 1 oppy" , Local _prty+l GOTO Floppy9133

LOOP

END LOOP

Lef t_i nternal :Outdisk*=": INTERNAL, 4, 1"

GOTO Disk_selected

Ri ght_i nternal : Outdi sk$= " : INTERNAL , 4 , 0"

GOTO Disk_selected

Hard91 33 :0Litdisk* = ":HP9 133, 700,0"

GOTO Di5k_5elected

Fl oppy9 1 33 : Out d i sk.t= " : HP9 1 33 , 702 , 0"

Disk_selected:OFF KEY

Print_di skdri ve: ! PRINT TABXY(62, 17) ;Outdisk*

RETURN

////////////////////////////////////////////////////////////

SUBEND

121
1 Oil) 102

104

106

108

1 1 112

114

116

IIB

120

124

126

128

130

132

134

136

138

140

142

144

146

148

150

152

154

156

153

160

162

164

166

163

170

172

174

176

178

180

132

184

186

188

190

192

194

196

193

20^' 202

204

2<J'-> 203

210

2 1 2

214

2 1 6

218

RF-STOF<fi "MODE BTIR"

Oriqinal: 22 May 19B4, G. Revision: 02 Oct 1985

Koep|::€?, NBG (303) 497-5766

The program is ciurrently con f i q(.ire(J as -follows:

1) Read diode detector on DV'M 1 [7223 (Horn antenna)

Calibr-ate this re^T^.ding via diode calibration

and nornialize to 10 mW/cfn'"2 re-ferenced to the

energy calculated via re-ference antenna as read

on the spectrum analyzer.

2) Read 1cm dipole output on DVM 2 i:723D and DVM 3 C724J

This is the EUT -for the measure?ment

.

Calibrate via calibration curve and

normalize to 37 dEi V/m as calculated from

reference received power.

3) In the event of failure to complete revolution

the program will modify sample count to comparisate.

4) Parameters set for NBS chamber.

5) Save dat£i is disabled, needs to be updated for Gf-;API-I_DAT

A

^-=== CHECI;; ALL CABLES AND PAD PLACEMEN"! S ===-.-.=.-====-r-.:=.

This measurement routine-? will operate the REVERBERATION CHAMBER

using MODE STIRED techniques. The tuner is stepped continuously

iind measurements ars performed asyr.cronusl y . In this S'ersion eacri

frequency is measured corripletely before proceeding

to thie ne;;t frequency.

Coupler, cable loss, and Power meter head corrections e^re applied

immediately to the mtjasured data.

The statistical results are saved for qraphiing.

OPTION BASE 1 DEC

PRINTER IS 1 OUTPUT 2 USING

DISP CHRt(129)

.#' "SCRATCH KEYX'

GOBUD Die graceful ly

G03UB Dim variables

G S U B Initial _v a 1 li es G03UB Fi Ileal ibration

GDGUB Do nieasurements

G G S U B D 1 e ^ g r a c: e f u 1 1 v D I S F' " F

• F-: O G \< A li F I rO 1 S H E D

' STOP

For a cleari slate.

/ / / / ////////// /

/

Dini ^variables: ! COM /Parameters/

COM /Parameters/

COM /Parameters/

/ ///*»( * *D 1 MENS J ON ^v^iR 1 AL:LES**x -x ///////////////

I Startf ,Stopf ,Stepf , SI ow_ down , Coupl er __i d$C 103

Generator_ i d t l 103 , Dvm_i ntegrat*C3

3

INTEGER Low dtam , Hi gh dbin , Eitep _dbm , Dvm_.sampl es COM /Parameters/ Upper 1 i mi t , Thireshol d , Rev_ t i me

122
21*0

-"» '-. '-> ^. •.A. 224

226

228

230

^-' j^ 234

236

23B

240

242

244

246

248

250

252

254

256

25B

260

262

264

266

268

270

272

274

276

278

280

2B2

284

286

283

290

292

294

296

298

300

302

304

306

308

310

312

314

316

318

320

324

326

328

330

332

334

336

338

Cnn .'Motor T'enu/ Mot i on_type*L lOD , INTEGER Jog_wait

COti /Ei(iq<=/ INTEGER Bug 1 , Buq2 . Liug3 , Pr i nter

Cum /Interrupts/ INTEGER lntr_prty

COM. /Fi iGs/ Sourcedi sl::f C20: , Outdi 5k:i-C20: ,Fi 1 enamefCSOD

I DIM Coup inc ( 100,2) ,CouD._rG-fl (100,2) , E^addat a_ i d* ( 10) [ BOD

DIM Cable6a(180,2) ,Cable6b ( 130,2) ,Cable4 ( 180,2) ,CablelOf t (180,2)

DIM Pad_aE6a(ie0,2) , Pad_56770 ( 180 , 2) ,Pad...-f 5530 ( 180 ,2)

DIM N=wc (180,2) !NSWC CABLE DATA

I DIM Cal _i dt-LBO: ,P:htL21 , Pwr_i d*L2D ,Te5t*[40 J INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

RETURN

Baddata ,Dbm,R-f _on_o-f -f Fail -flag

Val i d , Total -freqs. Total curves, Ser_pol 1 Ft i nt f- 1 ag , Read 1 -f 1 ag , Read2f 1 ag , Movi ngf 1 ag , F'ad lOdb

N5WC_pt5

Inc_pts,ReFl_pt5 ,C6a_pts

C6b_pts,C4_ptB,C10_pts,Pada_j:t5,Pad_pts,Pad-f_pts

Fcount ,Too_hot ,Print-f 1 ag2

Local __prty,F'_sams ,P,Dvml_sams ,Dvm2_5afn5

! ////////////////****INITIALIZE VARIABLES Z'. 1/0****/////////////

Ini ti al _val ues: ! ASSIGN ©Motor TO 706

ASSIGN <apwrl TO 709

ASSIGN (apwr2 TO 710

ASSIGN @Dual._pwrl TO 711

ASSIGN (SSpectrum TO 718

ASSIGN ©Dvml TO 722

ASSIGN @Dvm2 TO 723

ASSIGN (lDvm3 TO 724

ASSIGN (aSig.gen TO 719

IIntr _prty=6

Local ._prty=Intr_prty

Printer=701

Sourcedisk*=": INTERNAL , 4 ,0"

Outdisk*=": INTERNAL, 4, 1"

Pri nt-f 1 aq = Bug 1=0

Dug 2=0

Buq3--0

I Mot i on_t ype-T = " CONT I NUOUS

Rr.on o( 1=1

CALL Measure _menu

D vm 1 __sams=:Dvm_5amp 1 es

Dv/Ti2_ san-iS=Dvm_sanip 1 es CALL Menu_pwr436a

GOSUB Die _Qrace-f ul ly

lor "STEP" -For MODE TUNED.

) l=on, O=off

! Go and set up the measurement parameters.

! Set up all power meters

! For a clean slate.

123
;.40 I- - ALLOCATE THE RAW DATA MATRIX-

'•42 Tota:K-reqs=INT ( tStopf --Startf ) /Stspf ) +1

'44 Total cur veo=6

>46 ALLuCAl E Savedata ( Total fre-qs , Total CLirvcE+l ) 543 ALLOCATE Ad just ( Total f reqs , 10

)

3&4

356

353

3fc0 362

364

366

'.68 ;70

372

374

376

37B

380

382

384

386

383

390

392

394

396

398

40C> 402

404

406

4 OS

410

412

414

416

418

420

422

424

426

428

430

432

434

436

438

440

442

444

4 46

443

450

452

4b4

456

458

PRINIER 13 CRT

PR 1 NT T ABX V (1,18); RPT* ( " * "

, 20 ) ; " LOAD SUP. PROGRAMS

Fi lename-f =Generator__i d*?<Sourcedi sk*

DISP "Insert 'SUB Program/Support DATA' disk in "; SELECT Sourcedisk*

CASE •': INTERNAL, 4,0"

DISP "RIGHT DRIVE, "; CASE " : I NTERNAL ,4,1"

DISP "LEFT

END SELECT

;RPT*("*" ,20)

DISP "and hit

BEEP

ON KEY 5 LABEL

Zippy: BGTO Zippy

SLibload5:0FF KEY

DISP CHR*(12)

DISP " Signal

ON ERROR CALL

DRIVE, "; CONTINUE

"CONTINUE" ,Local_prty GOTO Subloads

Generator SUB

Errortrap

PROGRAMS NOW LOADING

LOADSUB ALL FROM Filename*

OFF ERROR

DISP " Signal Generator SUB PROGRAMS LOADED " WAIT 1

I PRINT TABXYd , IS) ;RPTf:("*" ,20) ; " LOAD CALIBRATION DATA "

; RPT*

DISP " Calibration DATA -for Cables, Couplers, Pads, etc. now

( "*" ,20)

LOADING

Iristall cal -f 1 Install new calibration -files here.

IF Printfl

IF Printfl

SELECT Cou

CASE "HP_7

Fi lena

Enter_

Bad d at

IF Pri

Fi 1 ena Enter_

Bad d at

IF Pri

CASE "HP_1

f^i 1 ena Enter ._ Baddat

IF Pri

f-i 1 eria

Enter _ Baddat

IF Pri

CASE ELSE

PRINT

BEEP

PAUSE

ag THEN

aq THEN

pl er_i d

73D"

me*="HP

cal data

a_id* (1 n t f 1 ag

nr,e*="HP

cal data

a_id$ (2

ntr lag

1692D"

lTiP*="HP

c a 1 d a t a

a__id.$ ( 1 n t T lag

me:t^="HP

c a 1 d a t a a_.id* (2

ntf 1 ag

PRINTER IS Printer

PRINT "CALIBRATION DATA FOR THE FOLLOWING IS LOADED:

_773D_-f "JiSourcedisi:*

(Fi lename* ,Coup_i nc (*) , Cal _i d$ , Inc_pt5

)

)=Cal_id*

THEN PRINT Cal_id*

_778D_r "?<Sourcedi sk$

(Fi Iename*,Coup_ref 1 (*) , Cal _i d* , Ref 1 _pts)

)=Cal_idt

THEN PRINT Cal._id*

1 1692D..f "?.Gourcedi3k*

(Fi 1 ename-f: ,Coup_i nc (*) ,Cal _ i d$ , lnc_pts)

*=Cal_id*

THEN PRINT Cal_id$

1 1692D_r"?<SourcBdi5k*

(Fi lenanie*,Coup_ref 1 <*) , Cal i d-T , Ref 1 _pt5)

)=Cal_.id*

THEN PRINT Cal id*

"COUPLER CALIBRATIOrj DATA ERROR NOT DEFINED.

124
460

462

464

466

46B

4/0

472

474

476

478

480

482

484

486

488

490

492

494

496

498

500

502

504

506

508

510

512

514

516

518

520

522

524

526

528

530

532

534

536

538

540

542

544

546

548

550

552

554

556

558

560

562

564

566

563

570

572

574

576

578

END SELECT

Fi lBname*="Csbl£?6FT_l "?<Sourcedi skit

Enter__cal data (Fi 1 ename*^ , Cabl e6a < *) , Cal _i dt , C6a_j)t5)

Eiaddata.J d* (3) =Cal _,i d-t- IF Pnntflaq THEN PRINT Cal_.id*

I Fi 1 enairie-t="Cabl e6FT _6"?<Sour cedi sk'f- Enter_caldata (Fi I ename* , Cab 1 e6b <*) , Cal _.i d* , C6b_.pt5)

niaddata_id* (4)=Cal_id*

IF Print-flag THEN PRINT Cal_id*

I Fi 1 ename*="Cabl e4FT _2"?<SoLircedi slr-f- Enter._caldata (Fi 1 ename* ,Cabl e4 (*) ,Cal_id f ,C4_..pts)

Baddata_id* (5)=Cal_id*

IF PrintFlag THEN PRINT Cal_id*

I Fi 1 ename*="Cabl elOF_5"?<Sourcedi sk*

Enter _cal data (Fi 1 ename* , Cabl elO-f t (*) , Cal _i d* , C10_pt5)

Baddata_id*(6)=Cal_id$

IF Print-flag THEN PRINT Cal_id*

I Fi lenan-ie*="PAD_S6770"?.;Sourcedi5k*

Enter._.caldata(Fi lename* ,Pad_s6770 (*) ,Cal __id* ,Pad_pt5)

Baddata_i d* (7) =Cal _i d*

IF Printflag THEN PRINT Cal_id*

I Fi lename*-"PAD_5530"?<Sourcedi 5k*

Enter._caldata (Fi 1 ename-f , Pad_-f 5530 (*) ,Cal _i d* , Pad-f _pts)

Baddata_idf-(8>=Cal_id*

IF Printflag THEN PRINT Cal_id*

1 Fi lenaiTie-*="PdAS6A1466"¥'.Sou.rcedi 5kt- Enter _cal data (Fi 1 enamet , Pad__a56a (•*) ,Cal_id* ,Pada_pts)

Baddata_id* (9) =Cal _id*

IF Print -flag THEN PRINT Cal_idt

I Fi lename*="PdAS6A1466"

Fi 1 e5riaiTie-f--=Fi 1 ename.t^'<Sou.rcedi sk'-f Enter _.cal data (Fil ename* , Nswc (-*) , Cal _i d* , NswcjDts)

Baddata_id*(10)=Cal..id*

IF Print-flag THEN PRINT Cal_.id*

DISP " Calibration DATA LOADED " WAIT 1 PRINTER IS CRT

CALL Wipe_ clean

DISP "INSERT OUTPUT DATA DISK IN SELECT 0utdi5k*

CASE ": INTERNAL, 4,0"

DISP "RIGHT DRIVE, "; CASE ": INTERNAL, 4, 1" DISP "LEFT DRIVE, "; END SELECT

DISP "and hit 'CONTINUE'."

BEEP

125
580

582

5B4

586

583

590

592

594

596

598

600

602

604

606

608

610

612

614

616

618

620

622

624

626

623

630

632

634

636

638

640

642

644

646

643

650

652

654

656

653

660

662

664

666

663

670

672

674

676

678

680

682

684

686

683

690

692

694

696

698

OtJ KEY 5 LADEL " CDtJl IMUE '\ Local ._pr ty GOTO DatasEO'er

Zippity:GOIO Zippity

DstaEaverrUFF KEY

DIGP CHR*(12)

RETUF.tJ

/ / / / / / / / / / / / / / / / / / / / / / /////*->.->< «D I E GRACEFULLY+i * *« / ///////////////

Di e gracerul 1 y : ! IF Bugl THEN

PRINT TIt1E*(TiriEDATE) ; PR I NT RPT* ( " <

"

, 1 5 )

; " DIE GRACEFULLY " ; RPT* < " > ",15)

END IF ON ERROR GOTO Del et_.clonel

SELECT Generator ._idi

CASE "HP„8660A"

DELSUB Set_f req , Set_dbm , FNDi gi 1 1 0* , F NDi gi t3* , FNRev*

CASE "HP._8672A"

DELSUB Set_.-freq,Set_clbm

END SELECT

Del et _donel : ! OFF ERROR

ON ERROR GOTO Del et__dorie2

DEALLOCATE Savedata (*) , Adjust (*)

Delet_done2: ! OFF ERROR

RETURN

////////////////////////////////////////////////////////////

2 Fi 1 1 cal i brat i on : IDetermine the cable, coupler and pad calibration

lvalues -for each -frequency.

ISave these in the adjust (*) -file -for use by the

! measurement routine.

IF Bugl THEN

PRINT TIME*(T1MEDATE) ; PRINT RPT*(" <" , 15) ; " FILL CALIBRATION MATRIX " ; RPT* ( " >" , 15)

END IF Fcount=l

FOR Frequency=Start-f TO Stop-f STEP Step-f

Get _cal _value (Frequency ,Coupi nc ,Coup_i nc(*) , Bad data, Inc_pt5)

IF Baddata THEN

Cal _i d*=Baddata_i d* (1

)

GOSUB Flagbaddata

END IF Adjust (Fcount, l)=Coupinc

Get__cal _ val ue (Frequ€?ncy ,Coupre-f- 1 ,Coup_re-fl (•*> , E>'addata , Re-f 1 _pts ) IF Baddata THEN

Ca 1 _.i d :f = Bad d a t a _i d f ( 2

)

GOSUB Flagbaddata

END IF Ad just (Fcount ,2) =Couprefl

Get_cal _va] ue (Frequency , C6a_l oss ,Cabl e6a ( » ) , Baddata ,C6a__pts>

IF Baddata THEN

Cal__id*--=Baddata_idf(3)

GOSUB Flagbaddata

126
700

702

704

706

70B

710

712

714

716

713

720

722

724

726

728

730

732

734

736

738

740

742

744

746

748

750

752

754

756

753

760

762

764

766

763

770

772

774

776

778

780

782

784

786

788

790

792

794

796

798

8<:i0 802

804

806

808

810

812

814

816

818

END IF Adjust (FcoLint , 3) =C6a .1 oss

Get__cal ._val ue (Frequency, C6b_losB,Cable6b () ,Eiaddata,C6b_ptE)

IF Baddata ThlCM

Cal idt = £iaddata_id* (4)

GOSUB Flaqbaddata

END IF Adjust (Fcount ^ 4) =C6b__l OSS

Get_cal_value (Frequency , C4_l oss,Cable4 («) , Baddat a , C4_.pt s) IF Baddata THEN

Cal _i d*=Baddata_i df (5)

GOSUB Flagbaddata

END IF Adjust (Fcount ,5) =C4_1 oss

Get _cal_value(Frequency,C10_l OSS, Cable 10ft (*) ,Baddata,C10_pts)

IF Baddata THEN

Cal _i d*=Baddata_i d* (6)

GOSUB Flagbaddata

END IF Adjust (Fcount ,6)=C10_loss

I Get._cal _val ue (Frequency , Pad_l oss ,Pad_s6770 (*) , Baddata, Pad _pts)

IF Baddata THEN

Cal_.id*=Baddata._idt (7)

GOSUB Flagbaddata

END IF Adjust (Fcount ,7) =F'ad__l oss Get_cal _val ue (Frequency , F'adf_l oss , Pad _-f 5530 (*) , Baddata , Pad-f_pts)

IF Baddata THEN

Cal J dit=-Baddata_.i d* (8)

GOSUB Flagbaddata

END IF

Adjust (Fcount ,8) =Padf_loss

I Get_cal _.val ue (Frequency , Pada_l oss , Pad_as6a (><> , Baddata , F'ada_pts)

IF Baddata THEN

Cal_id*=Baddata_idt(9)

GOSUB Flagbaddata

END IF Adjust (Fcount ,9) =Pada_l oss

Get cal _ val ue (Frequency , Nswc_.l ose,Nswc (*) ,Baddata , N5wc.jjt5)

IF Baddata THEN

Cal __id*=Baddata._id:f ( 10)

GOSUB Flagbaddata

END IF Adjust (Fcount ,10) =Mswc_lcss

I Fcount=Fcount+l

NEXT Frequency

GOSUB FT in tea lvalues

RETURN

////// ///////»***FLAG BAD DATA**** /////// ///////////////////

Flagbaddata: ! In-form the operator that there is wrong data

127
820

822

824

826

828

830

832

834

836

833

S-'IO 842

844

846

843

850

852

854

856

858

860

862

864

866

363

870

872

874

876

878

880

882

834

886

88S

890

892

894

896

893

900

902

904

906

908

910

912

914

916

913

920

922

924

926

928

930

932

934

936

933

Ibeinq brought bact^ from Enter _cal __data

I PRINTER IS CRT

PRIUr rALiXY (1,18);

PRINT RP (*("*", 10) ; " CALIBRATION DATA out o-f range -for "; Frequency

PR I NT " liHz "

; RPT* ( " * "

, 1 ) DISP Cal _ idf- BEEP

PAUSE

PRINT TADXr (1,13);

PRINT RPT*("*" , 10) ; " CALIBRATION VALUE OF dE WILL BE USED "; PRINT RPT* ( "*" ,10)

WAIT 3

PRINT TABXYd , 18) ;RPT*(" ",80)

DISP CHR* (12)

RETURN

////////////////////////////////////////////////////////////

Pr i ntcal val Lies: IMAKE LIST OF CALIBRATION VALUES USED.

PRINTER IS Printer

PRINT

PRINT RPT*("*" ,24) ; " CALIBRATI

PRINT

PRINT

PRINT

PRINT

PRINT

LoB5+rrit 1

ON / LOSS VALUES (dB) " ; RPT* ( "*" , 24

)

BLUE CABLES "; 5T" 6ft#l 6+t#6 4-ft lO-ft";

bl " #

,X) ,#

"Frequency Coupler

" S6770 F5530 ASA6A TE

MHz Inc Refl

" pad pad pad C

IMAGE M5D. D,X,4 (MDD. DD)

Lossf mt2: IMAGE 3(MDD.DD) ,2(MDD.DD

Los5fmt3: IMAGE MDD.DD

Fcount=l

FOR Frequency=Start-f TO Stop-f

Coupinc=10*LGT (Ad just (Fcou

Coupre-f 1 = 10«LGT (Adjust (Fco

C6a_.los5--10*LGT (Adjust (Fco

C6b_lo5S=10*LGT (Adjust (Fco

C4_loss=10*LGT (Ad just (Fcou

C10._los5=10*LGT (Adjust (Fco

Pad_lo5s=10*LGT (Adjust (Fco

Fad-f_lo5s=10*LGT (Adjust (Fc

Pada_l os5=10*LGT (Adjust (Fc

Nswc _1 OE5=10*LGT (Adjust (Fc

PRINT USING LossFmtljFrequ

PRINT USING Lo5S-fmt2; C4_lo

PRINT USING Lo5S-fmt3;N5wc_

Fcount=Fccunt+l

MEIXT Frequency

PRINT

PRINT RPTr ( "*" ,80)

PRINT USING "4/"

PRINTER IS CRT

RE r URN

I /////////////////////****PERFDRM MEASUREMENTS****///////////////

Do measurements: I

STEP Step-F

nt,l)

)

unt ,2)

)

unt,3)

unt ,4) ) nt ,5)

)

unt ,6)

)

unt, 7)

ount ,8)

)

ount ,9)

ount ,10)

)

Coupler incident

Coupler re-flected

6 foot BLUE cable #1

6 -foot BLUE cable #6

4 foot BLUE cables

10 foot BLUE cables

Weinschel S6770 lOdB pad

Weinschel F5530 lOdB pad

Weinschel AS6A-1466 lOdB

NSWC input cable

ency ,Coupi nc , Coup refl ,C6a_l oss ,C6b_I oss

ss , C10_l oss , Pad_l oss , Padf _1 oss , Pada_I oss

1 oss

128
940

942

944

946

948

950

952

954

956

958

960

962

964

966

968

970

972

974

976

978

980

982

984

986

988

990

992

994

996

998

1000

1 002

1 004

1 006

iooa

101

1012

1014

1016

1018

1020

1022

1024

1026-

1 023

1030

1032

1 034

1 036

1033

1040

1042

1044

1046

1043

1050

1 052

1054

1 056

1053

PRINTER IS 1 Fcount=l

DbiTi=Low_dbm

Frequency=Startf

BEEF- INPUT "ENTER THE RANGE

D I SP CHR* (12)

Plcm_scal e=. 1 Initial izemotor (SMotor)

Zeromotor ((SMotor)

Initialise the Generator Level

Initialise -first -frequency.

SET ON THE 1 cm D I POLE AMPL IFIER" , Plcm^scal e

REPEAT

! Initial valu£:-s and zeroing

IICalibration data for all cables,

I Pwrmtrcal l=FNPwrmtrcal 1 ( (Frequenc

Pwrmtrcal 2=FNPwrintrcal 2 ( (Frequenc

I Coupi nc=Ad just (Fcount , 1

)

Coupref 1 = Ad just (Fcount ,2)

C6a_l 055=Ad just (Fcount ,3)

C6b_l oss=Ad just (Fcount ,4)

C4_.loss=Ad just (Fcount ,5)

C10_l oss=Ad just (Fcount ,6)

Pad_loss=Ad just (Fcount , 7)

Pad-f _1 oss=Ad just (Fcount ,8)

F'ada__I oss=Ad just (Fcount , 9)

Nswc__l oss=Ad just (Fcount ,10)

probes, ?< power heads.

y>

)

! 18 GHz HEAD.

V)

)

!26 GHz HEAD.

Coupler incident

Coupler reflected

6 foot BLUE cable #1

6 foot BLUE cable #6 rcvr

4 foot BLUE cable

10 foot BLUE cable

Weinschel S6770 lOdB pad

Weinschel F5530 lOdB pad

Weinschel A56A-1466 lOdB

NSWC input cable

Dvml_5ams=Dvm_sampl es Dvm2_5am3=Dvm_safnpl es

Fai If lag=0

! The measurement will be attempted at

! the predicted number of samples first.

! These will be adjusted if failure occurs.

Restart: ! Any failure on this measurement causes branch to here.

Set_dbm (-140 ,Rf _on_of f ,@Sig_gen)

Set_-f req (Frequency , @Si g_gen ) Initial izemotor (©Motor

)

DISP CHR$(12)

I Setdcv3456a (@Dvml

)

Readdvm (Eut_zero ,(lDvml ) Setdcv3456a ((gDvm2)

Readdvm (Plcm_zero , (§Dvm2)

I Setdvm_3456a (@Dvml , Dvm_ i nteg'-at* ,Dvml_Eams)

Setdvm _3456a ((aDvm2 , Dvm_i ntegrat:*: ^ Dvm2_sams)

Setdvm 3478a (SDvm3)

Spec_ al zr__setup ((sSpectrum)

Zero _pwr_mtrs ( ©Pwr 1 , diPwr 2)

Ab*="AB'"

CALL Zero_438a((aDual _pwrl ,Ab*)

IIF NOT Fai If lag THEN

Dbm=Low dbm

129
l060

1062

1 064

L 066

l06S

L 070

.072

74

L076

.078

L080

:0B2

1084

.086

.088

. 090

: 092

.094

l096

L09B

1 00

102

104

106

108

110

112

1 14

116

US

1 20

122

124

126

128

130

134

136

138

140

142

144

146

148

150

152

154

156

153

160

162

164

166

168

1 70

172

174

176

178

Movemotcr ( i^Motor > PR I N r CUR* (12)

PRINT TABXV ( 1 ,3) ;TIME* (TIMEDATE) ; "*********«*****";

PRINT " FREQUENCY "; Frequency ; " MHz. **********»**"

PRINT TABXYd ,51 ; "FINDING THRESHOLD VALUE dBm="

PRINT TABXY (36,5) ; " Average EUT RE5P0NSE= " LOOP

Set_dbm ( Dbm , R-F _on_o-F -f , ©Si g__Qen ) Vave=0

,

FDR SamE=l TO 30

Readdvm 347aa (@Dvm3, V)

V'=V-F'lcm_ zero Vave=Vave+V

NEXT Sams

Vave=Vave/40

PRINT TAbXY(30,5)

;

PRINT USING "5D";Dbm

PRINT TABXY (60,5)

;

PRINT USING "3D.3D";Vave

EXIT IF Vave>=Thre-£hold OR Dbm>=Hi gh_dbm

Db(n=DbiTi+Step__dbfri

END LOOP

Stop_motor ( ©Motor

)

ELSE

Set_db;Ti (Dbm ,R-F_on_o-f f ,(aBig_gen)

END IF Fail-flag=l

Trigger measurement

DISP CHR-f(12)

Restart_jDoi nt2: ! Ab*="AB"

CALL Read_dLial _pwr ( Ab* , Apower , E-ipower , Too_hot , Val i d , ©Dual _pi-Jr 1

)

IF Too_hot THEN

GOBUB Redu.ce_power

GOTO Restart_point2

END IF

IF NOT Valid AND NOT Too_hot THEN GOSUB Dual _pwr_error

IF Apower<0. THEN Apcwer=0.

IF Bpower<0. THEN Bpower=0.

Incpwr_raw=Apower

Re-f pwr _raw=EpoiMer

. . . Sequence -for reading 436a Power meters..

F'wr__idt="rl " Read_pwr_meter (Power , F'wr _i d* , Val i d , (SPwr 1 , (5Si g_gen > IF NOT Valid THEN

DISP "ERROR IN 436a POWER METER 1" BEEP

PAUSE

END IF Incpwr=Incpwr _raw

Incp wr =Incpwr Coupi nc*Pwr mtr cal 1 / (C6b_l oss) line power at ANT

Re-f pwr=Ref pwr_raw*Coupre-f 1 *F'wrmtrcal l*C6b_l OSS !Refl pwr at AMT

Netpower= ( Incpwr-Re-fpwr)

I PRINT TIME* (TIMEDATE)

;

PRINT "*** START NEW MEASURMENT AT FREQUENCY = "; Frequency

i

130
1180 ON INTR 7 GOSUB Chc-ck_dvm_done

1182 ENABLE INTR 7;

lie^ Movemot or (©Motor)

1186 IF Buql THEN PRINT "DVMl trigger " ; T I MEt ( T I MEDATE )

; " "; 1188 Trigl._time^TIMEDATE

1 190 Tri qger _ 3456a ( ©Dvml

1192 IF Bugl THEN PRINT "DVM2 trigger " ; TIME* (T IMEDATE) ; " "; 1194 Trig2_,time=TIMEDATE

1196 Trigger_3456a (@Dvm2)

1 193 Spec_ al zr start (Frequency , ©Spectrum)

1200 IF Bugl THEN PRINT "TRIGGER ANALYZER " ; TIME* (T IMEDATE)

1202 Readlflag=0

1204 Read2-flag=0

1206 Vpeak=0

1208 LOOP

1210 Readdvm._3478a(©Dvm3,V)

1212 V=V-Plcm_zero

1214 IF V>=Upperlimit THEN

1216 Stop_niotor (©Motor

1218 REPEAT

1220 Dbm-Dbm-Step_.dbm

1 222 Set_dbm ( Dbm , R-f _on_of -f , @Si g_gen ) 1224 WAIT Slow_down

1226 Readdvm_3478a ((aDvm3,V)

1223 V=V-Plcm_zero

1230 BEEP

1232 PRINT "EUT MAXIMUM EXCEEDED **** POWER DECREASED TO "; 1234 PRINT Dbm;" dBm.

1236 UNTIL V<Upperlimit

1238 OFF INTR 7

1240 GOTO Restart

1242 END IF 1244 Check mot or (^Mot or, Mo ving-flag)

1246 IF NOT Movingflaq THEN

1248 PRINT "MOTOR NOT MOVING********DATA BAD"

1250 GOTO Restart

1252 END IF 1254 IF V>Vpeak THEN Vpeak=V

1256 Countdown=Rev_time- (TIMEDATE-Tr igl_ti me)

1253 Spy: IMAGE M4D.D," Seconds left, EUT mV=" ,M6D. 2D , " / ",M6D.2D,"

1260 DISP USING Spy ; Countdown , V*1000 , Vpeak*1000

1262 EXIT IF Readlflag AND Read2-flag

1264 END LOOP

1266 ! ================= === = ======== = ============:.= 1268 ! Make sure that the correct voltmeters are connected for this test

1270 ! IF (Vpeak+Eut_zero) >Hiqh2 THEN Hi qh2=Vpeak+Eut ._zer o 1272 ! ========= = = = ==:^=: = = = = = = = = = = = = =.=r ==: = = = r: = =:. = :=: = = 1274 OFF INTR 7 12:^6 FailfIan=0

1278 I 1280 ) InsLire successful (syncronized tuner and dvms) measurement.

1232 ! 1284 IF (Rcadl t i me :; . 93»Rev_t i me) OR (Read 1 . t i me>l . 02*Rev_t i me) THEN

1286 Dvml sams-INT ( (Rev_ t i me/Read l._ti me) *Dvml_5ams)

12G8 F'RINT "Dvm 1 NOT syncronized with TUNER REVOLUTION. "; 1290 PRINT "Changing samples to ";Dvml_5ams

1292 Failflag=l

1294 END IF 1296 IF (Read2_time<.98*Rev_timG) OR (Read2_t i me>l . 02*Rev_t i me) THEN

1293 Dvm2 5am5=INT ( (Rev time/Read2 time)*Dvm2 sams)

131
302

304

306

308

3 1 '.) 312

314

316

318

320

322

324

326

328

330

332

334

336

338

340

342

344

346

348

350

3&2

354

356

358

360

362

364

366

368

370

372

374

376

378

380

382

384

336

388

390

392

394

396

393

1400

1 402

1 404

1 406

1408

1410

1412

1414

1416

1418

PRINT "Dvm 2 NOT syncron i z e>d with TUNER REVOLUTION. "; PRINT "Changing samples to ";Dvm2_sanns

Fail-flaq=l

END IF

IF Fail -flag THEN

Stop_motor (OMotor)

GOTO Restart

END IF Spec_al zr_read (F'ower , Frequency , (iiSpectrum)

PRINT "SPECTRUM ANALYZER READS "; Power;" AT FREQUENCY "; Frequency

Stop_motor (©Notor

)

Set_dbm (-140 ,Rf _on _of -f , 03i g_qen >

I GOSUB Prccess._data

GOSUB Print_alldata

Frequency=Frequency + Step-f

Fcount=FcountH-l

UNTIL Frequency >Stop-f

I Set_dbm (-140,0 ,@Si g_gen

)

! GOSUB Save_dat5

RETURN

I

! ////////////////////////////////////////////////////////////

I Reduce_F'Ower : ! Dbm=Dbm-l

Set_dbm (Dbm , 1 ,@Si g_gen)

IF Printflag THEN

PRINTER IS Printer

PRINT TIME*(TIMEDATE) ; ": Freq=" ; Frequency

;

PRINT RPT$("*" , iO) ; " NEW GENERATOR LEVEL =";Dbm

END IF

RETURN

////////////////////////////////////////////////////////////

Dual _pwr_error : ! Set_.dbm (-140 ,0,@Sig_gen)

IF Frint-flag THEN

PRINTER IS Printer

PRINT TIMEI^(TIMEDATE) ; ": Freq=" ; Frequency;

PRINT RPT*("*" , 10) ; " ERROR IN DUAL POWER METER '!!"

END IF STOP ! F'rogram dies here!

RETURN

////////////////// / SERV I CE DVM ' S I NTERUPT / /////////////////////////

Check _dvn-i_done: IIR'espond to an INTERUPT on the HPIB generated by one o-f

I two HP3456a DVMs. Meaning that the data is ready.

Ser_pol 1=5P0LL ((aOvml)

ENABLE INTR 7 IF Ser_polI=66 THEN

Read 1 _t i me=T I MEDATE-Tr i g 1 _t i me

IF Bugl THEN PRINT "DVMl total sample time = " ; Read l_t i me; " "; IF Bugl THEN PRINT T I ME* ( T I MEDATE

)

132
1 420 ! 1 422 ! 1424 ! Si nee the output of the c/etepctor is negative, Low and High &re

1426 ! swapped.

1428 Readdvm__5tat (@Dvml ,Highl ,Lowl ,Meanl ^Varl ,Saml) ! Low and High swapped

1430 !

', . 1432

1434 Lowl=-l*Lowl iCrystal detector has negative output

1436 Highl = --l*Highl ! 1438 Meanl=-l*Meenl ! 1440 PRINT " DVM 1 = = = =", Low 1 , Hi gh 1

, Mean 1 , Var 1

, Sam 1 1442 Readl-flag = l 1444 END IF

1446 Ser_poll=SPOLL (@Dvm2)

1443 ENABLE INTR 7 1450 IF Ser_poll=66 THEN

1452 Read2_time=TIMEDATE-Trig2_time

1454 IF Bugl THEN PRINT "DVM2 total sample time = " ; Read2_t i me; " "; 1456 IF Bugl THEN PRINT TIME* (TIMEDATE)

1458 Read dvm_s tat (@Dvm2,Low2 ,Hi gh2 ,Mean2, Var2 , Sam2)

1460 PRINT ' DVM 2=====" , Low2 , Hi gh2 , Mean2 , Var2 , 3am2

1462 Read2flag=l

1464 END IF 1466 RETURN

1468 ! 1470 ! /////////////////****PROCESS DATA****/////////////////////////////

1472 ! 1474 Process .data: ! 1476 ! 1478 ! Cal cul at i ons -for power read -from spectrum analyzer.

1 400 ! 1482 Power= (. 001) *10-- (Power/10. > IConvert dBm to watts.

1484 Cor_power=Power*C10_loss«C6a_loss*Pada_loss

1486 I 1488 lALSQ EDIT PRINT STATEMENT IN LINE 1620

1490 ! 1492 ! Normalize to 10 mW/cm''^2

1494 ! 1496 Re-f _pwr_den= ( . 4*PI«Frequency*Frequency*Cor_power > /9. OE+4

1498 Normal _pwr=SaR (10/Ref pwr_den)

1 500 ! 7

1502 [Normalize to 37 dB V/m

1504 ! 1506 Re-f _e_-f iel d= (4*Pl*Frequency/300) *SQR (Cor_power»30)

1508 Normal f ld= (( (10. O- (37/20) ) /Re-f _e _f i eld) ) 1510 i 1512 '.Calculations for CRYSTAL detector with 6 ft cable,

1514 ! 1516 Cor _high 1= (Hi ghl-Eut _zero)

1518 Cor_mean 1= (Mean l-Eut_zero)

1520 IF Cor_highl<1.0E--50 THEN Cor_hi gh 1 = 1 . OE-50

1522 IF Cor mean 1 C 1 . OE-50 THEN Cor_mean 1 = 1 . OE-50

1 524 ! 1526 IF Cor_hiqhl<. = . 1 THEN

1528 Cor_hiqhl = .00304939*Cor_highl--(l. 1 195) 'Convert to WATTS

1530 ELSE

1532 Cor_highl = . 0135056*Cor_highl-(l .7488) I Convert to WATTS

1534 END IF 1536 ! 1538 Cor_hi gh l=Cor_hi qh 1*C10_1 oss

133
1540 Corjni qh l=CQr-_hi gh 1 *Norfnal _pwr*Normal _pwr

1542 Cor_ hiqhl=10*LGT (Cor_hi ghl /I . OE-3) IConvert to dBm

1544 I 1546 IF Cor meanl=.l THEN

1548 Cor_ meanl=.00304939*Cor meanl-(l. 1 195) IConvert to WATTS

1550 ELSE

1552 Cor_meanl = . 0135056*Cor_frieanl-- (1 . 7488) ! Convert to WATTS

1554 END IF 1556 I 1553 Cor mean l=Ccr__inean 1 *C1 0___1 055

1560 Cor_mean l-Cor__mean l*NorfTial _pwr*Normal _jDwr

1562 Cor__meanl = 10*LGT (Cor_meanl/l . OE-3) IConvert to dBm

1564 I 1566 I Cal cul at i ons -for 1 cm DIF'OLE with super amp.

1563 I 1570 Cor_high2= (Hi gh2-F'lcm_zero)

1572 RetLirn_-f ield (Cor_high2,Plcm_-f 1 d_high)

1574 Plcm_-f ld_high = Plcm_-f ld_t-iigh*Normal_-f Id

1576 New_vol ts (Plcm__-f 1 d _hi gh ,Cor_high2)

1578 ! 1580 Cor_(Tiean2= (Mean2-F'lcm_zsro)

1532 Return_-F ield ( Cor _mean 2 , Plcm_-f ld_mean)

15B4 F'lcm_-f 1 d_mean=Plcm_-f 1 d_mean*Normal _-f 1 d

1586 New_vol ts (Plcm___f ld_mean ,Cor_mean2)

1588 I 1590 IF Cor_high2<1.0E-50 THEN Cor __hi gh2=l . OE-50

1592 IF Cor_mean2 < 1 . OE-50 THEN Cor_mean2=l . OE-50

1 594 Cor _h i gh2=20*LGT ( Cor _h i gh2* 1 000

)

1596 Cor__mean2=20*LGT (Cor_mean2*1000)

1598 I 1 600 Savedata (Fccunt , 1

) =Frequency

1602 Savedata (FcoLint , 2) ==Net power

1604 Savedata (Fcount ,3) =Ref _e._-f i el d

1606 Savedata (Fcount ,4) =Cor _highl

1608 Savedata (Fcount ,5) =Cor_mean

1610 Savedata (Fcount ,6) =Cor_high2

1612 Savedata (Fcount , 7) =Cor_mean2 I dB mV

1614 I 1616 RETURN

1618 I 1620 I ///////////////////////****PRINT RAW DATA //////////////////////

1622 I 1624 Print_alldata: I 1626 PRINTER IS Printer

1628 PRINT

1630 PRINT RPT:f ("-" ,80)

1632 F'FcINT "**  if ************************" ; 1634 PRINT USING "2X , 6D. DD , 6A , 2X ,#"; Frequency ; " MHz " 1636 PRINT "*********>(***»'.****************"

1 633 PR I NT RPT* ( " - " , 80

)

1640 PRINT RPT*("_",80)

1642 PRINT "Measured RAW data:"

1644 PRINT

1646 PRINT " PWR IN MAX REC PWR HORN ZERO HORN PEAK";

1648 PRINT " HORN MEAN"

1650 PRINT " INC—Watts —REF Watts mV mV "; 1652 PRINT " mV"

1654 Spyrawl: IMAGE MD. 4DE , X , MD. 4DE , X X , MD. 4DE , XX , 6D. 2D , 3X , tt 1656 Spyraw2: IMAGE 70. 2D , X , 7D. 2D

165G PRI^JT USING Spyr awl ; Incpwr _r aw , Re-f pwr _r aw , Power , Eut_z er o k 1 0C)0

134

1 dB mV

1 dB mV

MHz

Watt:s V/m

dBm

dBm

dB mV
1660 PRINT USING Spyraw2; Hi gh 1 *1000 ,Mean 1 *1000

1662 I 1664 PRINT

1666 PRINT "1cm PRB ZERO 1cm PRB PEAK Icm PRB MEAN Signal Gen Level

1668 PRINT " mV mV mV dBm"

1670 Spyraw3: IMAGE 60. 2D , 6X , 7D. 2D , 6X , 7D. 2D , 1 OX , 5D

1 672 PR I NT US I NG Spyraw3 ; P 1 CfTi_.z ero* 1 000 , Hi gh2* 1 000 , Mean2* 1 000 , Dbn-, 1674 PRINT

1676 PRINT RPT* ("_" ,30)

1678 PRINT "PROCESSED DATA:"

1680 PRINT "HORN normalized to 10 mW/cm--2, 1cm DIPOLE normalized to 37";

1682 PRINT " dB V/m.

1684 PRINT

1686 PRINT "REC PWR CORR. HORN PEAK HORN MEAN "; 16S3 PRINT "1cm PRB PK 1cm PRB MEAN"

1690 PRINT " Watts dBm dBm "; 1692 PRINT " dB mV dB mV"

1694 Spyraw6: IMAGE MD. 4DE , 5X , M4D. 2D , 3X ,

#

1696 Spyraw7: IMAGE M6D. 2D , 2X , M4D. 2D , 4X , M4D. 2D

1698 ! 1700 PRINT USING Spyr aw6; Cor_power , Cor_hi gh

1702 PRINT USING Spyraw7; Cor_mean 1, Cor_hi gh2 , Cor_mean2

1704 PRINT TAB(41) ;RPT*("_" ,25)

1706 PRINT TAB (41 ); "Field V/m Field V/m"

1703 PRINT USING "39X , M4D. 2D , 4X , M4D. 2D" ; PI cm_-f 1 d_hi gh , Plcm _-f 1 d_mean

1710 PRINT

1712 PRINT RPT*("-",65)

1714 PRINT "REC PWR CORR. NET INPUT POWER REF PWR DENSITY REF FIELD"

1716 PRINT " dBm Watts mW/cm-2 V/m"

1713 SpyrawB: IMAGE X , M4D. 2D

,

lOX , MD. 4DE , 6X , M2D. 4D , 5X , M4D. 4D

1720 PowGr_dbm=10*LGT ( 1000*Cor__power ) 1722 PRINT USING SpyrawS; Power_dbm , Netpower , Re-f _pwr__den , Re-f _e_-f i el d

1724 PRINT RPT*("_",80)

1726 PRINT RPT*("*",80)

1728 PRINT RPTt<"_",80)

1730 PRINT

1732 PRINTER IS CRT

1734 RETURN

1736 ! 1738 ! /////////////////// ///****SAVE DATA****//////////////////////////

1740 ! 1742 Save__data: ! 1744 RETURN

1746 DISP "ENTER FILE NAME FOR THIS DATA (<=10 CHRS/NUMS ONLY) "; 1743 BEEP

1750 L INPUT Filename*

1752 IF LEN(Filename*) >10 THEN Save__data

1754 Pi 1 ename-f =F i 1 enameif ?(OLitdi skt- 1756 ON ERROR CALL Err or trap

1758 CREATE BDAT Fi 1 ename* , (7*Total -f regs+ 1 2B) , 8

1760 ASSIGN ^Datapath TO Filename*

1762 OUTPUT @Datapath;TotalcLirves

1764 OUTPUT ©Datapath; Total freqs

1766 OUTPUT ©Datapath; Total-freqs

1768 OUTPUT ©Datapath ;Savedata(*)

1770 ASSIGN ©Datapath TO * 1772 ! 1774 PRINTER IS Printer

1776 PRINT TIME*(TIMEDATE) ; " DATA STORED ON FILE "; 1773 PRINT Filename* LI ,POS (Fi 1 ename* , " : ")-ll; " "

135
1780

1732

1784

1786

1788

1790

1792

1794

1796

1798

1800

1802

1804

1806

1808

1810

1812

1814

1816

1818

1820

1822

1824

1826

1828

1 830

1832

1B34

1836

1838

1840

1842

1844

1846

1848

1850

1352

1854

1356

1853

1860

1862

1864

1866

1868

1870

1372

1874

1876

1878

1880

1882

1884

1SB6

1833

1 890

1892

1894

1896

1898

PR1NTEF< IS 1 OFF ERROR

RETURN

END

SUt< Measure menu. This routine will -facilitate setting up the

measurement

COM /Parameters/ Start-f ,Stop-f ,Stepf ,Slow_ciown , Coupl er_i d*C lO:

COM /F'arameters/ Generator _i d*C 10] , Dvm i ntegrat* C 3]

COM /Parameters/ INTEGER Low ._dbm , Hi gh_ dbm , Step_dbm , Dvm_sampl es COM /Parameters/ Upper 1 i mi t , Threshol d , Rev_t i me COM /Motor_menu/ Mot i on_type*L 103 , INTEGER Jog_wait

COM /Bugs/ INTEGER Bug 1 , Bug2 , Bug3 , Pr i nter

I DIM Eut__i denti ty*C 1603 , Operator_name*C603

1 PRINTER IS 1 Wipe_clean IClear the CRT.

Define the choices at start-up.

Operator_namBi^="Mi ke Craw-ford"

I Start-f =2000 I Frequency range in MHz.

St op f =4000

Step-f=200

Low_dbm=-30

Hi gh_dbm=-10

Step_dbm=l

! Signal generator level in dBm.

Eut_ident i ty*="Eval uate use of NSWC Reverberating Chamber " Eut_identi ty*=Eut_identi ty$?'."f or measuring response of EUT. "

Threshol d=50.

Upper 1 imi t = 1200.

I SI ow _down= . 02

Joq_ wai t = 10

!EUT LOWER THRESHOLD VOLTAGE. mV.

!EUT FAILURE VOLTAGE. mV.

!Time for EUT to respond after field is set.

'.Wait .10 seconds between each of 3200 Jogs,

Coupler._id*="HP_l 1692D"

Genorator__id*="HP__8672A"

Display the above parameters.

PRINT CHR-r(129)

PRINI TABXY(16. 1) ; " MEASUREMENT PARAMETERS FOR MODE STIRRED TESTS.

PRINT TABXY(1,3);" TEST DESCRIPTION: " PRINT TABXY(1,7);" FREQUENCY RANGE " PRINT TABXY(30,7) ; "TO"

PRINT TABXY (42,7) ; "STEP"

PRINT TABXY (56,7) ; "MHz .

PRINT TABXY(1,9);" SI6-GEN RANGE "

136
1 900

1902

1904

1906

190B

1910

1912

1914

1916

191B

1920

1922

1924

1926

1923

1930

1932

1934

1936

1938

1940

1942

1944

1946

1948

1950

1952

1954

1956

1958

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1930

1982

1934

1936

1988

1990

1992

19*^4 1996

1998

2000

2002

2004

2006

2008

201<1> 2012

2014

2016

20 1

Sp i n

Exit

PRINT TABXY(22,9) ; 'TO"

PR I NT TABXY (29,9)

, / M PRINT TABXV (37,9)

'dBm. " PRINr TAF:XY (44,9) ;

' EUT RESPONSE TIME " PRINT TABXY (70, 9)

' Sec. " PRINT TABXY (45, 11) ; " FAIL LIMIT mV " PR I NT TABXV (1,11); ' EUT LOWER THRESHOLD RESPONSE mV

PRINT TABXY (1 , 13)

' EST. TIMt/Tuner rev " PRINT TABXY (33, 13) ; " D'v'M SAMPLES " PRINT TABXY (53, 13) ;" LINE CYCLES/SAMPLE " PRINT TABXY (40, 15) ; " COUPLER/SIG GEN " PRINT TABXY ( 1,15); ' DATE/TIME " PRINT TABXY (1 , 17)

' OPERATOR'S NAME " PRINT

t CHR* (128)

IFill in the de-fau It choices.

GOSUB Print_eutid

GOSUB Print_-freqs

GOSUB Print_gen_level

GOSUB Print_eutf ail

GOSUB Print_5lowdown

GOSUB Print_thre5h

GOSUB Print_tuner

GOSUB Print_name

Make any changes or corrections.

OFF KEY

ON KEY LABEL "TEST ID",

ON KEY 1 LABEL "Frequency"

ON KEY 2 LABEL "GEN Levels

ON KEY ."T LABEL "THRESHOLD"

ON KEY 4 LABEL "FAIL LIMIT

ON KEY 8 LABEL "TUNER REVs

ON KEY 5 LABEL "CONTINUE"

ON KEY 6 LABEL "YOUR NAME"

ON KEY 7 LABEL "RESPONSE t ON KEY 8 LABEL "TUNER REVs

ON KEY 5 LABEL "CONTINUE"

ON KEY 9 LABEL " DATE ",5

BEEP

PRINT TABXY (14, 15) ;DATEf (T

D I SF' " < < < < < < < < PRINT TABXY (23,

GOTO Spin

5u.b : ' Up p er 1 i m i t =Up p

Thresh.ol d=Thre5

OFF KEY

DISP CHR-*(12)

PRINTER IS Prin

IF Printer=701

CALL Wipeclean

SUBEXIT

GOSUB Change_eutid

,5 GOSUB Change_-f reqs

",5 GOSUB Change_I evel 5

,5 GOSUB Change_thre5h

",5 GOSUB Change__eutf ail

",5 GOSUB Change_tuner

5 GOSUB E;:it_sub

,5 GOSUB Enter_name

m",5 GOSUB Change_respond

",5 GOSUB Change_tuner

5 GOSUB E>;it_SLib

CALL Time date

<< SELECT PARAMETER TO CHANGE

15) ;TIME± (TIMEDATE)

rl i mi t/ 1000 ' Convert to volti

hold/ 1000 I Convert to volts

ter

THEN DUMP ALPHA

I Change_tuner : I

137
202<.' 2022

2024

2026

2028

2030

2032

2034

2036

2033

2040

2042

2044

2046

2048

2050

2052

2054

2056

2058

2060

2062

2064

2066

206G

2070

2072

2074

2076

2073

2080

2082

2084

2086

2088

209(11

2092

2094

2096

2098

2 100

2102

2104

2 1 06

2108

2110

2112

2114

2116

2118

2 1 20

2122

2124

2126

2128

2130

2132

2134

2136

2138

Jog_wai t=Jog _wai t+1

Ft i nt_ tuner : I Rev_ti me=3a. 3706S*Joq_wai t+4 . 92406

I Dvm sampl es=INT ( 1 . 15* (38. 9729+23. 60333* (Rev_time) ) ) DviTi 1 ntegr"at*=" . 1"

1 cycle

IF Dvm_5ample=;- 9999 THEN

Dvm__samplE-5=INT (1.15* (3. 970653+1 2. 8621757* (Rev_ti me) > ) I 1 cycle

Dvm_i nteqrat-f =" 1 " END IF IF Dvm_5ample5>9999 THEN

Joq_wai t=0

GGTO Change_tuner

END IF Hh=Rev_time DIV 3600

Mm= (Rev_time-Hh*3600) DIV 60

Ss=INT(Rev_time-Hh*3600) MOD 60

PRINT TABXY(23, 13)

PRINT USING "DD,A,ZZ,A,ZZ";Hh,": " ,Mm,": " ,Ss

PRINT TABXY(47, 13) ; Dvm_sa,Tipl es PRINT TABXY(74, 13) ;

PRINT TABXY(74, 13) ;Dvm_integrat*

RETURN

I

Change^eut i d : ! DISP "DESCRIPTION o-F the EUT and PURPOSE -for test?? (<2 lines)";

OUTPUT 2 USING "K , #" ; Eut_i dent i ty*

L INPUT Eut_.identity*

Print_eutid: I PRINT TABXY (1 ,4) ;RPT.|:(" ",160)

PRINT TABXY ( 1 ,4) ;Eut_identity*

RETURN

/////////////////////////////////////////////////////////

Change_-f reqs: ! DISP "ENTER the START, STOP, and STEP -frequencies (MHz) "; INPUT Start-f ,Stopf ,Step-f IF Start-f < 100 THEN Start-f = 100

IF Startf>18000 THEN Startf =18000

SELECT Startf

CASE <2000

IF Stop-f:;2000 THEN Stop-f=2000

Coupler _.id*="HP_778D"

Gener at or _i d *= " HP _ 8660A

CASE ::=2000

IF Stopf. 18000 THEN Stop-f = 18000

Coupler._idr="HP_l 1692D"

Generator_id*="HP._8672A"

EfJD SELECT

Print_-freq5: ! PRINT TABXY (21,7);

PRINT USING "5D. 2D"; Start-f

PRINT TABXY (33,7)

PRINT USING "5D.2D";Sto'j-f

PRINT TABXY (47,7)

PRINT USING "5D.2D";Step-f

138
2140

2142

2144

2146

2143

2150

2152

2154

2156

215B

2160

2162

2164

2166

2168

2 1 70

2172

2174

2176

2178

2180

2132

2184

2186

2188

2190

2192

2194

2196

2193

2200

2202

2204

2206

2203

2210

2212

2214

2216

2218

2220

2224

2226

2228

2230

2234

2236

2238

2240

2242

2244

2246

2243

2250

2252

2254

2256

2253

2260

2262

2264

2266

2268

2270

2272

PRINT TABXY(58, 15) : RPT* ( " ",10)

PRINT TAEXY(69, 15) ;RPT*(" ",10)

PRINT TABXY(58, 15) ; Coup 1 er _i dt

PRINT TABXV (69, 15) ; Generator_i d*

RETURN

I

1 Change_l evel s : !

i DISP "ENTER Signal generator LEVEL (dBm) ";

I INPUT Dbm

1 Lo^J_dbm=INT (DbiT.) DISP "LOW, HISH, STEP Signal generator LEVEL (dBm) "; INPUT Low_dbm , Hi gh_dbm , Step_dbm

Pri nt_gen_l evel : ! PRINT TABXY(17,9)

PRINT USING "4D";Low_dbm

PRINT TABXY(24,9)

PRINT USING "4D";High_dbm

PRINT TABXY(32,9)

PRINT USING "4D";Step_dbm

RETURN

I

Change_eut-f ai 1 : ! DISP "ENTER the UPPER LIMIT -for the EUT RESPONSE (mV)";

INPUT Upperlimit

Pri nt_eLttf ai 1 : ! PRINT TABXY(60, 11) jUpperl imit

RETURN

Chanqe_thresh: ! DISP "LOWER LIMIT EUT RESPONSE -for initially setting -field. (mV)

INPUT Threshold"

Pri nt_thresh: ! PRINT TABXY(35, 11) ;Thre5hold

RETURN

I

I Change_respond : I DISP "WAIT TIME FOR EUT TO RESPOND AFTER FIELD IS SET.";

INPUT Slow_down

F'r i nt_sl owdown : I PRINT TABXY(64,9) ;RPT*(" ",6)

PRINT 1 ABXY(64,9) ;Slow_down

RETURN

I!////////////////////////////////////////////////////

I Enter_name: I DISP "PLEASE TYPE IN YOUR NAME "; LINPUT Operator-_name.f

Pri nt_name: I PRINT TABXY(20, 17) ; CI ear ^opname*

PRINT TABXY(20, 17) ; Operator_name*

RETURN

////////////////////////////////////////////////////////////

SUBEND

I

139
NBS-n4A iREv. 2-80) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions;

1. PUBLICATION OR

REPORT NO.

NBS/TN-1092

2. Performing Organ. Report No 3. Publication Date

April 1986

4. TITLE AND SUBTITLE

Design, Evaluation, and Use of a Reverberation Chamber for Performing

Electromagnetic Susceptibility/Vulnerability Measurements

5. AUTHOR(S)

M. L. Crawford and G. H. Koepke

6. PERFORMING ORGANIZATION f/f joint or other than N 6S, see in struct /on sj

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9, SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS fStreet. City. State. ZIP)

Naval Surface Weapons Center (NSWC) , Dahlgren, Virginia

and

Rome Air Development Center (RADC) , Griffiss Air Force Base, Rome, New York

10. SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or /ess factual summary of most significant information. If document includes a significant

bi bliography or literature survey, mention it he-'ej This report presents the results of work at the National Bureau of Standards,

Boulder, Colorado, to carefully evaluate, document, develop (when necessary),

and describe the methodology for performing radiated susceptibility/vulnerability

measurements using a reverberation chamber. The report describes the reverberation

chamber theory of operation, construction, evaluation, functional operation, and use for performing immunity measurements. It includes an estimate of measurement

uncertainties derived empirically from test results and from comparisons with

anechoic chamber measurements. Finally, it discusses the limitations and

advantages of the measurement technique to assist potential users in determining

the applicability for this technique to their electromagnetic compatibility

(EMC) measurement needs.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

electromagnetic susceptibility/vulnerability; estimated uncertainty;

evaluation; measurement procedures; reverberabtion chamber

13. AVAILABILITY

[2Q Unlimited

I I For Official Distribution. Do Not Release to NTIS

[X] Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.

[]3j Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

146

15. Price

irU.S. GOVERNMENT PRINTING OFFICE:1986- 671-453/45156 USCOMM-DC 6043-P80


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