FILE COPY

NBSIR 76-844 [__wm^m

RECEIVED

1 OT?

A MICROWAVE VECTOR VOLTMETER SYSTEM

Keith C. Roe

Cletus A. Hoer

Electromagnetic Division

Institute for Basic Standards

National Bureau of Standards

Boulder, Colorado 80302

August 1976

Sponsored by

Department of the Air Force

USAF School of Aerospace Medicine

Brooks Air Force Base, Texas 78235

NBSIR 76-844

A MICROWAVE VECTOR VOLTMETER SYSTEM

Keith C. Roe

Cletus A. Hoer

Electromagnetic Division

Institute for Basic Standards

National Bureau of Standards

Boulder, Colorado 80302

August 1976

Sponsored by

Department of the Air Force

USAF School of Aerospace Medicine

Brooks Air Force Base, Texas 78235

U.S. DEPARTMENT OF COMMERCE, Elliot L Richardson. Secretary

Edward 0. Vetter , Under Secretary

Dr. Betsy Ancker-Johnson . Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

Q

CONTENTS

Page

ABSTRACT 1

I. INTRODUCTION 1

II. DESCRIPTION 1

General 1

Seven-Port Junction 2 System Operation 4

III. SEVEN-PORT CALIBRATION 7 General 7 Broadband two-position insertion device 7 Broadband three-position phase shifter 10

IV. MEASUREMENT 12

Applications 12

Tasks 13

V. OPERATING PROCEDURE

.

14

Turn-on 14

Program 15

Operating 15

VI. ERRORS i 16

Detector nonlinearity 16

Step attenuator nonrepeatability 16

Frequency drift 17

Leakage signals 17

Signal level variation 18

VII. EVALUATION * 18

System repeatability 18

Intercomparison 18

VIII. TROUBLESHOOTING 20

IX. BIBLIOGRAPHY 21

APPENDIX A - USING AN ARBITRARY SIX-PORT JUNCTION TO MEASURE

COMPLEX VOLTAGE RATIOS 23

APPENDIX B - CONTROL COMMANDS USED IN THE COMPUTER

OPERATING PROGRAM 33

APPENDIX C - COMPUTER PROGRAM DESCRIPTION AND LISTING

WITH SAMPLE PRINTOUT 37

APPENDIX D - INTEREACE CABLE PIN CONNECTIONS 53

APPENDIX E - DIAGNOSTIC PROGRAM LISTING WITH SAMPLE PRINTOUTS . . 61

iii
LIST OF FIGURES

Figure Page

1. The microwave vector voltmeter system 2

2. A front view of the microwave vector voltmeter 2

3. The seven-port junction and isolators used in the MW ....... 3

4. The seven-port junction and its diode detectors 4

5. Circuit used for self-calibration, measurement and

diode linearity in the MW system 5

6. A view of the chassis containing the seven-port

junction and self-calibration circuitry 6

7. Using a quadrature hybrid (Q) and a power divider (D)

to make an insertion ratio of 3 dB with 45° phase shift .... 8

8. A two-position repeatable insertion device ............ 8

9. Insertion loss and phase shift of the broadband

two-position insertion device 9

10. A broadband three position phase shifter 10

11. Photograph of a broadband three-position phase shifter 10

12. Phase shift through the quadrature hybrid shown in figure 1

relative to the bottom coax line, measured on the NBS

automatic network analyzer 11

13. Some measurement configurations using the microwave vector

voltmeter. Device D may be either a power divider or a directional coupler 12

LIST OF TABLES

Table Page

I. Attenuation Measurement Difference (dB) 19

II. Phase Shift Measurement Difference (degrees) ... 19

IV
A MICROWAVE VECTOR VOLTMETER SYSTEM

Keith C. Roe and Cletus A. Hoer

This report presents a system description and operating

procedure for a vector voltmeter system which covers the

frequency range .5 to 12 GHz. The design is based upon

a seven-port junction where phase and amplitude information is obtained using only power detectors. The system

is computer controlled and self -calibrating for ratio

measurements

.

KEY WORDS: Amplitude; computer controlled; diode

detectors; microwave measurements; phase anqle; selfcalibration; seven-port junction; vector voltmeter.

I . INTRODUCTION

The theory for using six, seven, and eight-port junctions to measure

circuit parameters has developed rapidly at the National Bureau of Standards

in the past three years [1 - 7]. One of the applications of that theory is a microwave vector voltmeter (MW) used to make measurements of complex

substitution loss, or gain, ratios.

This report describes a complete MW system which includes a seven- port junction, computer, digital voltmeter, multiplexing unit, switching

circuits, and self -calibration devices.

II. DESCRIPTION

General

The MW system has two input ports or channels (labeled "reference" and

"test") for comparison of voltage level changes in the test channel while the

reference channel level is maintained constant. The complex ratio of the

voltage change in the test channel may be measured at any frequency in the

0.5 to 12 GHz range with power levels not exceeding +10 dBm at either of the

two input ports. The lower limit of nower at the reference port is -20 dBm

and at the test port is -70 dBM.

The basic design of the TTW is based upon the six-port concept [1 - 7]

where phase and amplitude information can be obtained from a set of amplitude

measurements. (In the MW, diode detectors whose outout voltages are very

nearly a linear function of the square of their respective input voltages are used to indicate amplitude levels.) The seven-port approach may be regarded

as an augmented version of the six-port technique. This was motivated by

preliminary experiments, which indicated an improvement in measurement precision with one additional power detector.

A block diagram in figure 1 shows the interrelationship between the

major parts of the complete system. All interconnecting lines in figure 1 represent interface cables for switching control or data transfer.
The computer is used for data storage and calculation as well as automatic control of the system to minimize operator involvement and reduce the

time required for the calibration and measurement processes. The switch

driver, multiplexer and DVM are necessary for automatic control and data

handling.

Seven-Port |^

and

Self

Calibration

Circuits

Switch

Driver

Multiplexer

DVM

Computer

Keyboard

Printer

and

Display

Figure 1. The microwave vector voltmeter system.

More detail is given in the following sections concerning the operation

and functions of the MW components shown in figure 1. Figure 2 shows the

assembled system where the multiplexer, DVM, switch driver, seven-port and

self-calibration circuits are contained within the cabinet on the right and

the computer and keyboard are in the cabinet at the left.

Figure 2. A front view of the microwave vector voltmeter.

Seven-Port Junction

The seven-port junction is constructed using quadrature hybrid 3 dB

couplers (Q) and 3 dB power dividers as shown in figures 3 and 4.

-2-
For incident waves ai and a 2 at ports 1 and 2 the ideal response at

each of the power detectors P 3/ P 5 , P 6 , P 7 and P 8 would be proportional to

the quantities indicated in figure 3, The ratio of the two incident waves

would be

a

( Ps ~ P?) + j (P 6 ~ Pe ) (1) ai P 3

Since non-ideal components are used resulting in reflections, losses

and uneven power division, the seven-port junction must be analyzed in a more general way. This is done in Appendix A for a six-port junction. A

minor extension of that analysis can be performed for a seven-port junction

resulting in equations (1) through (10), (Appendix A) where the summations

are taken over 5 detectors instead of 4. The result is (from (10),

Appendix A)

y z . P . * a— = K n , 1 = 3,5,6,7,8 (2) E w. P.

The terms K, z^, and w^ , are constants of proportionality that can be determined in calibration. For measurements of the ratio of two different values

of a 2 (a! remains constant) the complex constant, K, does not need to be known,

Since one of the z. =1 and one of the w. = 1, this leaves four complex z. and

1 l c x four real w^, to be determined by the calibration. The self calibration

process is described in Section III of this report.

P6 c»|a,-ja2

2

P 3 o|ai

J — Q

1

P8 a|a,+Da 2 | P5 o|a,+a 2 | 2 *** Q

T

» Q

_ Port 1

P7 o|ai-a 2 | Port 2

b 2 + A

Figure 3. The seven-port junction and

isolators used in the MW.

The subscripts are so labeled to be consistent with previous publications.

-3-
Figure 4. The seven-port junction and diode detectors.

System Operation

To make measurements the seven-port junction must first be calibrated,

and then switched into a measurement routine. Three routines are available

through software (Appendix C) supplied with the system. These routines are:

1. Self Calibration

2. Measurement

3. Diagnostic.

These routines contain control commands (Appendix B) which set the

switches shown in figures 5 and 6. The four outer switches (1, 3, 6, 7) are set to "M" to measure or position "C" to calibrate the seven-port junction. The three inner switches (2, 4, and 5) are set to "S" -for calibration

and measurement or to "D" for diagnostics and diode linearity.
1±±±1

SEVEN-PORT

JUNCTION

Isolator

.5-12 GHz

3-position

Dhase- shifter

T

7

Isolator

.5-12 GHz

Reoeatable

Insertion

Device

0 - 15 dB

5 dB steps

Isolator

.5-12 GHz

0 - 15 dB

1 dB steps

/\ REFERENCE A TEST

Figure 5. Circuit used for self -calibration , measurement

and diode linearity in the MW system.

-5-
Figure 6. A view of the chassis containing the seven-port

junction and self calibration circuitry.

-6-
III. SEVEN-PORT CALIBRATION

General

The self -calibration procedure is almost identical to the procedure outlined in [7] and reproduced in Appendix A. The only change is that i goes

from 3 to 7 instead of 3 to 6

.

Six independent measurements of the repeatable insertion device are obtained corresponding to these six nominal settings of <f> 0 (three-position

phase shifter) and a B (0 - 15 dB ; 1 dB step)

.

oio (dB) <p 0 (degrees)

t) 0°

0 120°

0 240°

3 240°

3 120°

3 0°

These values of attenuation and phase shift for a : and $ o were chosen to

obtain six symmetrically spaced points in the complex plane. The values are only approximate and need not be known for the self -calibration process. The

only requirement is that no two points coincide for any frequency in the range

0.5 to 12 GHz.

The attenuation change, a 0 , is easily obtained using commercially available equipment, however, the phase shifter (<j> 0 ) and the repeatable insertion

device (L) are specially constructed to obtain broadband operation. More detail is provided about those circuits and their operation in the following

sections

.

Broadband two-position insertion device

In calibrating the seven-port junction, the complex insertion ratio L

of the repeatable two-position insertion device must not have a phase angle

of 0° or multiples of 90°. A phase shift of 45° is probably optimum, but

doesn't need to be exact or known. One way of getting 45° phase shift over

a broad frequency range is shown in figure 7. The two outputs of the quadrature hybrid (Q) are equal in amplitude but 90° out of phase. Adding these

two signals with an in-phase power divider. (D) gives a signal that is shifted

45° relative to the input signal. In addition to this 45° there will be some phase shift B due to. the lengths of line through 0 and D. The length of the

lower path can be adjusted to give a phase shift equal to 9 . The phase difference in the two switch positions will be 45° over the complete frequency range

of the hybrid and divider, which is the same as the frequency range of the

-7-
seven-port. The amplitude of the insertion ratio will be approximately 3 dB.

The assembled two-position insertion device is shown in figure 8. Measurements of the phase and insertion ratio are shown in the graph of figure 9.

A/V

>

OUT

0 DB L§L

Figure 7. Using a quadrature hybrid (0) anc' a power divider (D)

to make an insertion ratio of 3 dB with 45° phase shift,

Figure 8. A two-position repeatable insertion device.
Figure 9

4 6 8 10

FREQEUNCY, GHz

Insertion loss and phase shift of the

broadband two-position insertion device,

12

-9-
Broadband three-position phase shifter

The phase shifter shown in figure 10 gives three different values of

phase over the usable frequency range of the quadrature hybrid (Q) .

open

Q

| ±90°* e"

o o

e°

Figure 10. A broadband three-position phase shifter.

Going through the hybrid (Q) the phase shift is theoretically either

0 - 90° or 0 + 90° depending on whether the outputs are shorted or open.

The phase shift 0 is a residual phase shift due to the length of line through

the hybrid. The electrical length of the lower path is adjusted to equal 0, so the three relative values of phase are 0°, -90° and +90° over the bandwidth at the hybrid coupler.

The center conductors at the two open circuited terminal planes were

recessed 1.65 mm to equalize the electrical lengths of the shorted and open

paths. The assembled three-position phase shifter is shown in figure 11.

Results of measurements for both the shorted and open conditions relative

to the bottom path are shown in figure 12.

Figure 11. Photograph of a broadband threeposition phase shifter.
-130 1

i : ' :

0 2 4 6 8 10 12

FREQUENCY, GHz

Figure 12. Phase shift through the quadrature hybrid

shown in figure 1 relative to the bottom coax line,

measured on the NBS automatic network analyzer.

-11-
IV . MEASUREMENT

Applications

Several types of measurement can be performed using the MW. Three

types are shown in figure 13. Some additional applications are described

in [8] and [9]

.

(a)

M V V 1 c

INSERTION

—o o

POINT

M V V

SOURCE

(b)

i— STANDARD

l I] SHORT

I AW UNKNOWN

HDOPEN

SOURCE

(c)

M V V 7z

X INSERTION —O o- POINT

Figure 13. Some measurement configurations using the microwave vector voltmeter. Device D may be either

a power divider or a directional coupler.

For the measurement shown in figure 13 (a) , the item under test must be

a two-port device or system connected at the insertion Doint. The measurement configuration shown in figure 13 (b) is for one-port devices and the

configuration of figure 13(c) may be used for either one-port or two-port

devices

.

-12-
Tasks

Appendix C contains a listing of the program used to calibrate the

seven-port junction and make measurements. This program contains a list of

eight tasks which can be performed individually or sequentially. These

tasks are:

1. Calibrate

2. Measure reference

3. Measure test device

4. Measure DVM offset voltages

5. Measure R 0 and C

6. Monitor reference diode voltage

7. Measure insertion step value

8 . To determine K for absolute ratio measurements

9. To measure and average ratios with test device

inserted

.

Tasks 1, 2, and 3 are intended to be used most frequently where task 1 (calibrate) must, of course, be used before any measurements are made. Task

2 establishes a reference voltage ratio and task 3 measures a test voltage

ratio relative to the reference voltage ratio. Any number of test voltage

ratios may be measured relative to a reference or the option exists to

reestablish a new reference ratio at any time by selecting task 2. Each

time a task is completed the system will pause and wait for a new task

selection which may be selected by entering the number of the task at the

keyboard followed by an execute command.

The reference ratio is the value

oz . P

a_2 = v 2-,_i ; E i i w

i p ^ i = 3 . . . 7 (3)

and the test ratio is the value

a 2 _ v 2- i i = K

p

t , i = 3 . . . 7 (4)

i a ! 2>i

The insertion ratio R is computed from these two ratios

R = . ( 5) a 2 /a.i

Tasks 4 (measure DVM offset voltages), 6 (monitor reference diode

voltage) , and 7 (measure insertion step value) are available for general

information about the complete system in case there is some question about

the measurement results.

-13-
Task 5 (measure R 0 ) is performed at the end of the calibration procedure

automatically, however it may also be performed at any other time when applicable. Its purpose is to establish a zero input reference at the terminal

plane of the test device insertion point. Establishing a zero reference

value increases the reliability of the measurements for high values of insertion ratio, 4 0 to 60 dB. The need for this measurement is due to non-ideal

isolation between input ports 1 and 2 which allows some of the signal at port

1 to go through the seven-port junction and appear at port 2. Portions of

this leakage signal are then reflected from discontinuities in the transmission line leading from port 2 to the insertion point. The effect of

this leakage signal is measured and cancelled out of the measurements of

the test signals.

Task 5 also allows the operator to input a value for the absolute power,

P , incident at the input reference terminal of the MW. Measurement of the

rincident power can be accomplished using a calibrated bolometer-coupler. The

program then calculates a value for C in

i=7

P = cVw. P. (6) r i x

i=3 so that the reference power can be monitored and printed by the calculator.

If this is not useful information, simply input P = 1 when the calculator

asks for P and then, ignore the P column. Ratio accuracy is not affected

by the value input for P . Task 8 allows K in (3) to be determined. The operator is instructed to

apply two signals equal in amplitude and phase to the test port and to the

reference port so that a 2 /ai = 1 + jo. Other reference ratios of a 2 /ai are then calculated relative to this first one. Task 9 is a special routine to be used where source power stability is a problem. This task changes the sequence of reading the diode output voltages

on the seven-port junction. All diode voltages are measured as fast as possible taking one reading from each diode. The voltage ratio a 2 /aj is

measured 2 to 25 times depending on the value of K6 in line 5140 of the MW

program. The average ratio is then computed. Results of the measurement

are calculated using (5).

V. OPERATING PROCEDURE

Turn-on

First make sure that excessive microwave power levels are not present

which could damage the diode detectors. Fifty milliwatts is considered

excessive, however power levels of 10 milliwatt or less are recommended.

-14-
Turn on the ac power switch on the front panel of the voltmeter chassis

and the computer and high-speed printer.

The front panel push button controls on the DVM should be set to "DC"

and "Auto". The multiplexer push button controls should be set at "PWR",

""REM" and "EXT". The multiplexer first ooint and last point thumbwheel

switches should be set to 0 and 3 0 respectively.

Procrarr. Load the program stored on file 2 of the cassette tape by pressing

consecutively

:

Load

2Execute

.

Cperarir.g

When the program has been loaded into computer memory it may be executed

by pressing "Run" and "Execute" . The computer will display or print questions

and instructions. Questions can be answered through the keyboard while instructions can be acknowledged after completion by pressing "Cont" (continue)

and "Execute". For example: The first question displayed when running the

program is "Frequency (GHz)?" The operator responds by typing the frequency

and pressing execute. The computer responds by setting the switches for the

correct isolators in the MW and then lists the eight available tasks on the

high-speed printer. Trie :;srar:r may then select the appropriate task by

typing the number of the task and pressing execute.

In general, it is desirable to set the power levels so that the test

and reference channel power levels are approximately the same magnitude.

The reference channel may be monitored by selecting task 6 and should be set

so that the reference diode output level is between 5 and 10 millivolts

.

When the frequency is changed the program should be started over (press

Run, Execute) so that the isolators will be reset. The system will need to

be recalibrated also. The system can be stopped at any time and returned to

the "Next Operation" question by pressing:

Stop

Cont 400

Execute

.

-15-
VI . ERRORS

The major sources of error are:

1. Detector nonlinearities

2. Step attenuator nonrepeatability

3. Frequency drift

4. Leakage signals

5. Signal level variation

The following is a description of these errors and of methods used to

reduce them.

Detector nonlinearity

This is the largest single source of error in the MW. Diode detectors

are used because of their small size, availability, simplicity, and ease of

instrumentation; however, the output voltage response is not proportional to

input power over a wide dynamic range. Some major factors affecting diode

response are diode loading impedance and ambient temperature.

To improve the diode response curve each diode detector has an output

loading resistor which was selected for the most optimum square-law response

by comparing the diode output with known input power levels measured using a bolometer bridge power meter.

In addition, the diodes are temperature controlled to within approximately ±0.1 degree Celsius using an aluminum block with a heater and

temperature sensor controlled by a proportional oven temperature control

circuit

.

Step attenuator nonrepeatability

Self calibration of the seven-port junction is a process where six equations are produced relating the step attenuator value to two groups of power

measurements. A basic assumption in solving the six simultaneous equations

is that the step attenuator value is the same for each equation. If this

is not true then the results may not fit to any lower value of precision

than the precision of repeatability of the step attenuator.

-16-
Repeatability tests on the step attenuator produced standard deviations

for groups of 10 steps of about 0.001 dB . A major factor which can increase

the nonrepeatability is connector loosening due to vibrations from repeated

switch closures. To reduce this effect a periodic check using the diagnostic routine (file 4 on cassette tape) is recommended which monitors the step

repeatability for groups of five step closures. The connectors on the step

may be retightened to improve the repeatability. Do not overtighten, since

excessive torque may ruin the connectors on the switches.

Frequency Drift

Frequency variations from a microwave source will affect any phase

measurement in a two-channel system if the two channels do not have equal

electrical lengths. For example, a path length difference (id) of one meter in air dielectric coaxial line will result in a phase change (AP) of

12 degrees when the frequency varies by 10 MHz. The relationship is

„ p = 360 :d If

c where If is the frequency variation during the measurement period and c is

the velocity of propagation.

Within the MW, electrical lengths have been equalized for both channels

in the measurement and calibration circuits; however, electrical path length

differences external to the MW can contribute to phase changes as well, so this effect must be considered. Both frequency control and equalization of

external path lengths are recommended to minimize this source of error. Leakage Signals

Isolation between the input ports 1 and 2 at the seven-port junction is

required so that any change in ~-, or 7 2 due to a change in a ; or a 2 is

negligible. (See Appendix A, eq . 18)

.

V, =

a- (1 + r 2 ) V x a x (1 + r,)

Isolation across the seven-port junction is greater than 40 dB, however

this small amount produces significant errors when the measured insertion

loss is 40 dB or greater. This effect has been reduced to approximately

60 dB by using the "measure R Q " routine described previously in Section IV.

-17-
Signal Level Variation

An error can appear in calibration of the seven-port junction if the

signal level varies during the time between measurements with the step in

and the step out. From Appendix A equation (20)

a' £Z i Pi

L = it

= £z7pt ' 1 = 3

• • • 7

' (7)

L is the insertion ratio of the two-position insertion step attenuator. A

change in signal level from the microwave source between measurements of

a 2 and a'2 will introduce an error in the calculation of L and therefore an error in the calculation of the seven-port constants. This error will have

the same effect as the previously described error from step attenuator non- repeatability .

VII. EVALUATION

System Repeatability

Measurement precision and accuracy may vary from time to time depending

on such factors as microwave source stability, step repeatability, and

operating power levels. A reliable check on measurement precision appears in

sigma of the self-calibration printout. Sigma is the standard deviation of

differences between the calculated and measured values of the step attenuator

for each of the six calibration measurements. If sigma is less than 0.03 dB

the calibration is good and measurements should repeat to about the same value for insertion ratios up to about 20 dB. Above 20 dB the errors should

increase approximately one order of magnitude for each 20 dB increment of

insertion change in the test channel.

Intercomparison

A measurement comparison between the MW and the NBS network analyzer

has been performed using a 0 - 70 dB (10 dB steps) attenuator. Isolators

were connected on both sides of the attenuator and measurements were made

in the octave frequency range between 4 and 8 GHz using both systems.

Results of that intercomparison are given in table I and table II.

-18-
Table I.

Attenuation Measurement Difference (dB)

ANA - MW

Frequency

J U QrJ A fi ATI U do D U urs

4.0 0.35 .07 .07 .49 1.7

4.5 0.27 .03 .31 .07 1.1

5.0 0.10 .08 .06 .15 0.2

5.5 0.05 .04 .13 . 06 0.5

6.0 0.02 .07 .14 .41 1.5

6.5 0.02 .01 .00 .26 0.8

7.0 0.01 .05 .31 .17 0.0

7.5 0. 01 .01 .01 .11 0.6

8.0 0.07 .04 .32 .42 1.3

Table II.

Phase Shift Measurement Difference (degrees)

ANA - MW

Frequency

GHz 10 dB 20 dB 30 dB 4 0 dB 50 dB

4.0 0.6 1.1 5.7 8.6 32.3

4.5 0.01 0.1 1.8 0.8 6.5

5.0 0.3 0.6 0.2 6.2 10.5

5.5 0.3 1.1 3.9 11.2 37.8

6.0 0.5 0.6 2.1 3.9 59.1

6.5 0.2 0 . 6 0.2 1.4 1.0

7 . 0 0.5 0.5 2.2 0.3 0.3

7.5 0.7 0.6 1.1 1.1 2 . 3

8.0 0 . 2 0.3 7.3 2.4 3 . 0

-19-
VIII. TROUBLESHOOTING

The following table lists some troubles that may occur during operation

of the MW system, their probable cause and cure. Those troubles due to malfunctioning commercial equipment contained

within the system should be referred to the respective manuals (supplied with

the system) covering that equipment.

Trouble Probable cause and/or cure Program won '

t

converge to

correct solution

in self-calibration

procedure

.

Bad data

CAUSE: 1. Data incorrect due to power level —too

high or too low.

2. Switches not functioning.

3. Data transfer error caused by transient

noise or interface cable trouble.

CURE: 1. Compare data with samples of good data

that did converge.

2. Check switches by running diagnostic program to measure step repeatability and

cycle the switches.

3. Check for adequate signal level in both

the reference and test channels in the

calibration and measurement modes.

4. Rerun the self -calibration routine.

CAUSE: 1. Equipment not on.

2. Interface cables loose.

3. Scanner not setting correctly.

4. DVM malfunction or controls at wrong

setting

5. Attenuators not switching correctly.

6. Switches sticking on phase shifter or repeatable step.

CURE: 1. Check equipment and cables.

2. Cycle switches.

3. Watch scanner during self-calibration

routine to see if the scanner is

changing channels properly.

4. Check data from the DVM, display data

transferred to the computer and make

sure it is the same as that displayed

on the DVM.

5. Monitor diode voltage levels to see if

there is sufficient signal present in

both channels in the measurement and

calibration modes.

-20-
Trouble Probable cause and/or cure Improper Switching

Program won't load

CAUSE: 1. Switch sticking

2. Switch driver malfunctioning

3. Interface cable disconnected.

CURE: 1. Cycle switches several times using the

diagnostic routines and listen for audible

switching noise. If no switches work,

check the switch driver, interface cables,

and statements in the program which control

the switching functions. See Appendix C.

If some switches work but others do not

the switches may be bad or the driver output power level may be low. If possible

substitute switches.

1 . Bad tape

2. Dirt or residue on tape reader

3 . Computer out

1. Clean the tape reader then reload the

program.

2. Load program from another tape.

3 . Check computer manual

.

CAUSE;

CURE

IX. BIBLIOGRAPHY

1. Hoer, C. A., Theory and application of a six-port coupler, NBS report

(unpublished)

.

2. Hoer, C. A., The six-port coupler: A new approach to measuring voltage,

current, power, impedance, and phase, IEEE Trans. Instrum. Meas .

,

Vol. IM-21, Nov. 1972, p 466-470.

3. Engen, G. F. and C. A. Hoer, Application of an arbitrary six-port

junction to power measurement problems, IEEE Trans. Instrum. Meas.,

Vol. IM-21, Nov. 1972, p 470-474.

4. Hoer, C. A. and G. F. Engen, Analysis of a six-port junction for measuring

v, i, a, b, z, 7, and phase, presented at the Proc . IMEKO Symp.

Acquisition and Processing of Measurement Data for Automation,

Dresden, Germany, June 17-23, 1973.

5. Engen, G. F., Calibration of an arbitrary six-port junction for measurement of active and passive circuit parameters, IEEE Trans. Instrum.

Meas., Vol. IM-22, Dec. 1973, p 295-299.

6. Hoer, C. A., Using six-port and eight-port junctions to measure active

and passive circuit parameters, National Bureau of Standards (U.S.),

Tech. Note 673, Sept. 1975, 23 pages.

7. Hoer, C. A. and K. C. Roe, Using an arbitrary six-port junction to measure complex voltage ratios, IEEE Trans. Microwave Theory and

Techniques, Vol. MTT-23, No. 12, Dec. 1975, p 978-984.

8. How vector measurements expand design capabilities, Application note 91,

Hewlett-Packard Company, January 1968.

9. Vector voltmeter measurement techniques, Application note 22, PRD Electronics, Inc., May 1971.

-21-

APPENDIX A

USING AN ARBITRARY SIX-PORT JUNCTION

TO MEASURE COMPLEX VOLTAGE RATIOS

The following report is reproduced in its entirety because it

provides the theoretical background for the MW system. All

work in this Appendix and in the main body of the report

represents the same effort, therefore repetition can be avoided

by referral to portions of this Appendix which cover the applicable subject.

-23-

978 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. MTT-23, NO. 12, DECEMBER 1975

Using an Arbitrary Six-Port Junction to

Measure Complex Voltage Ratios

CLETUS A. HOEK, member, ieee, and KEITH C. ROE, member, ieee

Abstract—An arbitrary six-port junction is analyzed as a micro- wave vector voltmeter, measuring the amplitudes and phase differ- ences of two input signals in terms of power readings taken at the remaining four ports. The junction may be calibrated for measuring

the complex ratio of these two signals using a self-calibration proce- dure which requires no attenuation or phase standards.

Manuscript received April 14, 1975. This work was partially supported by the Naval Sea Systems Command, USAFSAM, and

the Army Metrology and Calibration Center. This is a contribution

of the National Bureau of Standards not subject to copyright.

The authors are with the National Bureau of Standards, Boulder,

Colo. 80302.

INTRODUCTION

PERHAPS the greatest impact in the field of CHI"

and microwave measurement in recent years has been

the introduction of the automatic network amil\ zer (ANA). In contrast with the prior art where the key to improved accuracy was usually an improved hardware

item, the procedure now is to measure the hardware imperfections and adjust the measurement results in such a way as to account for them. The key to this correction process is in the measurement of the phase as well as

Copyright ©1975 by The Institute of Electrical and Electronics Engineers, Inc. or Printed in U.S.A. Annals No. 512MT004
HOER AND ROE: COMPLEX VOLTAGE RATIOS

amplitude of the complex parameters involved. The meas- urement of this phase has generally involved conversion

to a lower frequency which complicates the detection

process. Although phase detection circuits which operate

at microwave frequencies are well known, these have generally assumed ideal components, and are not particularly

suitable for automation.

Recent theoretical studies of an arbitrary six-port have

provided an alternative method of obtaining the phase

information without requiring either frequency conversion

or ideal components. [1], [2], [7]. One of the unexpected

results of this study is that most of the earlier six-port

designs for getting phase information provide a set of data which is ill conditioned from the viewpoint of the more general theory. Fortunately, the theory also suggests

how to design the six-port junction to eliminate this condition. This paper shows how the ratio of two complex volt- ages or two complex wave amplitudes can be measured

using an arbitrary six-port junction where four of the

ports are terminated with power meters. If two coherent

signals of the same frequency are applied to the remaining

two ports, the junction gives the phase angle between

the two signals as well as the amplitude of both in terms

of the four power meter readings. The six-port junction

thus becomes a vector voltmeter in which phase and

amplitude information are calculated from power measurements. The six-port junction can be calibrated for making

complex ratio measurements without using any standards.

The only precision component needed in the calibration

or measurement setup is a two-position step attenuator whose change in insertion ratio must be highly repeatable,

but need not be known. Its value is determined in the

calibration process along with other unknown constants

describing the six-port. The complete calibration process

is readily automated, requiring no operator involvement.

Accuracy of ratio measurements is determined primarily

by the linearity of the four detectors. Precision components are not required to make precise ratio measurements.

The analysis of a six-port junction as a vector volt- meter is similar to that of a six-port junction used for power [1] or impedance [2] measurements.

GENERAL THEORY

Consider an arbitrary six-port junction shown in Fig. 1, where four ports are terminated with power meters. If the junction is linear and only one mode is present at

Fig. 1. An arbitrary six-port junction with power meters on four

of the six ports.

979

each port, the scattering equations for the junction can be written

6 b. = £ S«aj, i = 1..-6 (1)

where a, and b t are the complex incident and emergent wave amplitudes and the Sij are the scattering parameters of the junction. Assuming that the power meters on arms 3 —6 are permanently connected

o, = bjTj, j = 3-.-6 (2)

where Ty is the reflection coefficient of the power meter on port j. Equations (1) and (2) represent a collection of ten linear equations in terms of the twelye variables

di,bi, i = 1* "6. This system of equations may be solved '

for any ten of these variables as functions of the remaining two. In particular, it is possible to write

bi = Aiai + BiOi, i = 3- --6 (3)

where A t and 5, are functions of the scattering param- ij eters of the junction and the reflection coefficients of the

power meters. Multiplying (3) by its complex conjugate j yields

| 6, | 2 = | A, | 2

| ax | 2 + AiBfaiOz* + AfBtvfa*

+ | £, | 2

| a, | 2

, i = 3- • -6 (4)

where (*) indicates complex conjugate.

If the phase angles fa, fa, and <t> are defined such that

Oi = | Oi | exp ( jfa) , (h = \ (h\ exp ( jfa) (5) L and

<t> = fa — fa then (4) becomes

p. — = I Ai | 2

| ai I 2 + (AiBi* + Ai*B,) I ai(h I cos <t> Ki

+ | Bi | 2

| (h I 2 + j(Ai*Bi - AiBi*) | <n<h | sin fa

i — 3 • • • 6 (6)

where Pi = K{ | 5, | 2 is the power indicated by the meter on the iih port, and /C, is a constant. This expression

represents a linear system of four equations in the four

unknowns | ax | 2

, j «2 | 2, | ajOj | cos fa and | a\Oi | sin fa If these equations are independent1 they may be inverted

to obtain each of the four unknowns as a linear function

of the four P, {i — 3 —6). The result is

I o, | 2 = E PiPi (7a)

I <h I 2 = X *<Pi, i = 3- "6 (7b)

y

| a\Oi | cos 4> = XiPi (7c)

!

| ai(h | sin <f> = Z ViPi (7d)

1 It is this condition that is not satisfied by most older six-port

designs used for getting phase information from amplitude measurements. See the section on "Six-Port Design Criteria." -26-
980 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, DECEMBER 1975

where each sum in (7) and throughout this paper is over

the four sidearm power readings, i = 3 —6. The coeffi- cients of Pi are real numbers which are functions of the

! parameters 5tJ and r,-. Equations (7) constitute the dei sired result and are valid for any linear six-port junction

subject to the conditions mentioned. The ratio 02/01 can

be written

Oi

O2 exp ( j(j>)

tti

I di

Using (7) this becomes

(h £ fa + jUijPi

- (cos <t> + j sin <(>) .

. (8)

ai £ PiPi

(9)

A more useful form of (9) for calibration purposes is obtained by factoring xm + jym out of the top sum and

factoring pn out of the bottom sum to get

a2 £ ZiP — = K

ai where

K =

Zi =

£ WiPi

Jm + jym

Pn

x< + jyi xm + jym

(10)

(11)

(12)

IVi Pi

Pn and where m and n can each be either 3, 4, 5, or 0. For

many applications the complex constant K does not need

to be known. Since zt = 1 when i = m, and wl = 1 when

i = n, this leaves only three complex z, and three real w{ to be determined.

COMPLEX VOLTAGE RATIOS

The voltage at the two input ports can be written

Vi = Oi + b„ i = 1,2 = o.a + r<)

where I\ is the complex ratio 6,/a, at port i

Oi

Yi — S22 + S21

Oi

02

(14)

(15)

(10)

(17)

The scattering parameters in (16) and (17) are those of the equivalent two-port which results when the four side- arms of the six-port junction are terminated with power

meters. The ratio of the two input voltages is

02(1 + r,)

(18)

that there is sufficient isolation between input ports 1 and

2 so that any change in Tj or T2 due to a change in ax or

02 is negligible.

SELF-CALIBRATION PROCEDURE

All of the constants in (10) except A' can be determined

by a self-calibration technique which does not require any

standards. The technique is based on earlier work described by Allred and Manney [3]. A calibration circuit such as shown in Fig. 2 ir, used. A signal is divided into

two channels which are connected to the inputs of the

six-port junction. The signal Oi in one channel is held constant by internally leveling the generator and isolating

it from the signal 02 in the other channel which contains a level set attenuator a0 , phase shifter <t>0 , and a twoposition insertion device. Data for calibrating the six-port

junction are obtained by noting the value of all Pi for the

two positions of the insertion device at different settings of a0 and 4>o. The value of the insertion device does not need to be known, but it must be highly reproducible

and independent of signal level. The initial value of at relative to ax is determined by

the setting of a0 and <j>o, which also need not be known.

When the insertion device is switched to its second position, a2 changes to a2

' and the power readings change

from Pi to P/. Assuming that Oi is constant during the

time it takes to read the Pi and P/, (7a) and (13) give

£ wtPi = £ WiP/.

(13) The ratio of 02'/o2 obtained from (10) is

a2 £ ZiP/

£ ZiPi

(19)

:20)

This L is the change in insertion ratio of the two-position

insertion device. The ratio of | 02'

| 2 /| a? \ 2 obtained from

(7b) is

L I 2 = £ UjP/

£ UiPi

(21)

where Ui = tr./o-/ and I is either 3, 4, 5, or 6. Since Ui = 1, there are only three u, to be determined in (21)

.

The measurements of P,- and P/ are repeated fur four

aid + ro

The voltage ratio will be proportional to 02/01 provided

-27-

Setup for calibrating and using a six-port junction to measure complex voltage ratios.
HOER AND ROE: COMPLEX VOLTAGE RATIOS 981

or more different settings of a0 and <j>o. Each different

setting gives additional equations like (19) -(21), where

L is the same for each measurement. These three sets of equations can be solved for the calibration constants z,-, Wi, and Ui and also for L. To assure that L remains constant when ao and <j>o are changed, and that Oi remains constant at the two positions

of L, isolators are added as shown in Fig. 2. Further

analysis may show that not all of the isolators are needed.

CALCULATING SIX-PORT CONSTANTS

When the complex insertion ratio L is known, it can be

thought of as a ratio standard in calibrating the six-port

junction to obtain the constants ziy Wi, and However,

it is not necessary that L be known; L can be treated as simply one more unknown constant to be determined.

When L is not known, (20) is a nonlinear equation which

can be solved by writing it in the form

/ = T.zdLPi - Pi') = 0 (22)

and expanding /in a Taylor series about the best estimates

of Zi and L

S^U+H— A2i- + -'4 Ah = 0 (23)

ifLm dZi dL

where fQ is the value of/ calculated from (22) using best

estimates of Zi and L. The partial derivatives

dZi

BROAD-BAND TWO-POSITION INSERTION

DEVICE

In calibrating the six-port junction, the complex inser- tion ratio L of the repeatable two-position insertion device must not have a phase angle of 0° or multiples of 90°. A phase shift of 45° is probably optimum. One way of getting 45° phase shift over a broad frequency range is shown in Fig. 3. The two outputs of the quadrature

hybrid (Q) are equal in amplitude but 90° out of phase.

Adding these two signals with an in-phase power divider

(D) gives a signal that is shifted 45° relative to the input

signal. In addition to this 45° there will be some phase

shift 0 due to the lengths of line. The length of the lower

path can be adjusted to give a phase shift equal to 0. The

phase difference in the two switch positions will be 45° over the complete frequency range of the hybrid and

divider, which can be the same as the frequency range

of the six-port. The amplitude of the insertion ratio will be -3 dB.

The optimum value of | L | has not been determined.

Values near 3 and 8 dB have been used with no noticeable

difference in results.

\f 3 dB /45° + 9

°

OUT

= LPi - Pi' (24)

Fig. 3. Using a quadrature hybrid (Q) and a power divider (D)

to make an insertion ratio of 3 dB with 45° phase shift.

dL £ ziPi (25)

are also calculated using best estimates of Zi and L.

Initial estimates of 3% to use in (25) and in calculating

fo can be determined by solving (22) for the Zi using an

estimate of L as a known value. A set of four or more

equations like (23), which is linear in the unknowns Azt and A/y, is solved for these four unknowns which are then

used to improve the estimates of Zi and L

new Zi = old new L = old

Zi + AZi

L + AL.

(26)

(27)

These new estimates of z { and L are used in (23) and the

iteration repeated until the A's become insignificant. Once

L is determined, (21) becomes linear in the three un- known Ui so that three or more equations like (21) can be solved directly for the

The constants p„, a u and xm + jym cannot be deter- mined by this calibration process. However, for measuring

complex insertion ratios, these constants are not needed.

Complex insertion ratios of 02/02 can now be measured

using the known 2, in (20). If only the amplitude of L is desired, it is somewhat simpler to calculate [ L | 2 using

the real ul in (21) rather than the complex 2, in (20).

Using the Zi and in (10), ratios of 02/01 can be measured

to within a constant K.

SIX-PORT DESIGN CRITERIA

As one might expect, not all six-port junctions are equally useful in making measurements of | ai |, | ai \, and

<j>. One useful design is an extension of the phase discrimi- nator or correlator circuit which is a six-port device often

used to get phase information from amplitude measure- ments [4]. Fig. 4 shows a correlator constructed from

three quadrature hybrids and one in-phase power divider.

If the components are ideal, the phase angle is calculated

from Pb

• • • Ps using

4 I Oi02 I COS <f> = I Oi + O2 I 2 = k(P6 - P7 )

4 I 0102 I sin <t> = \ ax — JO2

=- k(P6 - Ps )

ai — 02 (28)

2 _

(29)

ai + J02 I 2 (30)

(31)

i'GWS 1 "-

J L

0 D n r

1*1 - J' •G>'

: J @1*1 * j»> r

Fig. 4. A correlator constructed from one power divider (D) and

three quadrature hybrids (Q). Ideal components would give out- puts proportional to the values shown.

-28-
982 IEEE TI

where k is a constant. Although the correlator is a six-port

device, the equations in (7) do not apply in the limit when

the correlator becomes ideal because the four outputs are not linearly independent. The identity

| Oi + 02 | 2 + ! di - (h ! 2 = | Oi — jai ; 2 + | ai + ja2 | 2

(32)

shows that the correlator has only three independent out- puts since any one output can be obtained from the other

three. In a sense, the correlator by itself is only a five- port junction. One more independent output must be

added to the correlator to have (7) apply. Since the

correlator alone cannot give | ai | 2 and | 02

1

2 which do come out of (7) , we might expect that adding an output

proportional to ] ai | 2 or ] aj | 2 would make a valid set of four independent outputs. This is indeed the case. Fig. 5 shows a correlator with two power dividers and two more

detectors added to make | a.\

j 2 and j 0% | 2 available. The

six outputs are listed in Table I. It can be shown

that a set of four independent outputs is obtained by

choosing one from each group in Table I, plus a fourth

output which can be any one of the six not already

chosen. For example, if ] a\ | ~ | 0% j, a six-port vector voltmeter could have outputs approximately proportional to

I 0.1 I 2

, I CLl + 02 j 2, I Oi — jd2 | 2

, I Oi | 2

. (33)

Or if I 02 I <3C I ai I one might design the outputs to ap- proximate

I ai | 2

, [ d + 02 | 2

, \ ai — ja^ | 2 and

I ai — 02 | 2 or \a1 +jai \\ (34)

Here \ ai — j 2 or I ax + jch \ 2 is used instead of ] 02 | 2 because | 02 | 2 might be too small to measure, but ' ai — ~ or j a.\ + ja2 ; 2 would still contain useful information

about 02. As with other six-port applications, the outputs listed

Fig. 5. Adding two power dividers (D) to a correlator to make an

eight-port junction having several combinations of four inde- pendent outputs.

TABLE I

Group 1 Group 2 Group 3

I a i ( 1 la, - ja 2|

|ai * ja,| J

Note: A set of four independent outputs is obtained by choosing

one from each group plus a fourth which can be any one of the six not already chosen.

ISACrrir ^s ON MICROWAVE THEORY AND TECHNIQUES, DECEMBER 1975

in Table I are only design goals. The actual outputs of a

six-port junction can depart considerably from these val- ues and still be quite useful. For example, the output

I d\ + j(h | 2 indicates that ideally ai and 02 would be 90°

apart at detector 8. But the output is still useful even though the phase difference is ±60° from the ideal 90°. When the outputs depart greatly from those in Table I, the coefficients of P, in (7) become large so that the

desired information is obtained from the difference between large terms in the r<am. As the individual terms in the sum become significantly larger than the quantity on the left of the corresponding equa*sign in (7), greater

precision is required in measuring each P, to obtain a

given accuracy.EXPERIMENTAL SETUP

An eight-port junction following the design shown in

Fig. 5 was constructed from commercially available miniature coaxial X-band components with SMA connectors. This was converted to a six-port by terminating ports 7

and 8 with loads so that the remaining four outputs

are approximately proportional to those in (33). A photograph of the junction is shown in Fig. 6. The components

in the photograph are identified in Fig. 7 which also shows

how the signals are combined to get the desired outputs.

Four diode-type power meters having a linearity of ±1

percent from 10 nW to 10 ftW were used as detectors. The

power level into each diode was kept less than 10 nW to assure square-law operation.

Fig. 6. Experimental six-port junction and power detector mounts.

CORRELATOR

Fig. 7. Identifying the components in Fig. 6, where Q indicates quadrature hybrids, and D indicates an in-phase power divider. The signals labeled at different parts of the circuits are those obtained from ideal components if the two input signals are 2v2ai and 2V2~a2 . -29-
HOBR AND ROE: COMPLEX VOLTAGE RATIOS 983

Fig. 8. Experimental six-port X-band vector voltmeter setup. From left to right: programmable calculator, input/output

expander, DVM and scanner, four-power meters, six-port junction (on white paper), and two-input signal lines.

Since the six-port calibration and measurement process

requires taking many sidearm power measurements, it is most desirable to have the data read directly into a computer which can then process the data. A programmable

calculator is capable of taking the necessary sidearm power

readings under program control, and then processing the

data to give the calibration constants and measurement

results. Basic language programs have been written for calibrat- ing the junction as a microwave vector voltmeter, and

also for using it to measure complex insertion ratio. After

calibrating the six-port junction using the setup in Fig. 2, the same setup is used to measure complex insertion ratios by either changing or inserting something in the test (lower) channel, and using (20) to calculate the ratio. A picture of the setup is shown in Fig. 8. The same

setup can be used with any type power detectors that

have an output dc voltage which is a known function of the input power level. RESULTS

Preliminary measurements have been made on this setup

at 8-12 GHz. The complex insertion ratio of the twoposition step attenuator L, was measured with the six- port junction and then measured by the National Bureau

of Standards ANA. The results are shown in Table II. The agreement is within what one would expect using

detectors linear to only 1 percent. Better power detectors

should give greater accuracy. The comparison shows that

the theory of using an arbitrary six-port junction as a TABLE II Amplitude and Phase Change in the Two-Position Step Attenuator as Measured by the Six-Port with Diode

Power Meters and by the National Bureau of Standards ANA

FREQUENCY, GHz. 8 9 10 11 12

SIX-PORT 7.82 7.58 7.52 7.91 8.53

ANA 7.75 7.57 7.<48 7.92 8.36

ATTE DIFFERENCE .07 .01 .Oh -.01 .17

sTx-PORT ».B 33.19 31.19 31.00

1

PHASf DEC ANA 38.09 31.81 32.15 31.73 30.91 DIFFERENCE .06 -.68 .71 -.21 .09

vector voltmeter is correct. It also shows that the six- port junction can be calibrated without using any standards. The only precision component in the setup is the

two-position step attenuator whose change in insertion

ratio is repeatable to ±0.001 dB.

OTHER APPLICATIONS

Once the six-port vector voltmeter has been calibrated,

it can be used to measure the complex reflection coeffi- cient of a one-port device by using it on the sidearms of a reflectometer. The setup in Fig. 2 can be converted to a

reflectometer by inserting a directional coupler at the

"insertion point" as shown in Fig. 9. The resulting re- flectometer can be calibrated to measure T at the reference plane using established techniques [5], [6]. If it is desired to measure only T with the setup, the six-port vector voltmeter can be calibrated as before with the directional

coupler permanently fixed at the insertion point. A sliding

short at the reference plane could then take the place of

</>o. The reflection coefficient is calculated from

A (02/01) + B

1 + C(o2 /o1 ) (35)

where A, B, and C are complex constants. Note that al- though K in (10) is not known, it can be thought of as being part of A and C which are determined in calibrating

the reflectometer. It is, therefore, not necessary to know

K for this application. If the only application of the six- port junction is to measure T, it is probably better to

calibrate the junction directly as a reflectometer using

other techniques which do not require isolators [7].

DISCUSSION

The experimental system described here could be simplified to make a relatively inexpensive automatic measure- ment system of moderate accuracy. The six-port component and diode detectors could be fabricated in one

stripline package. Since measurements are made directly at the test frequency, no local oscillator (LO) or phaselocked sources are required to heterodyne the signal to some lower frequency. The six-port concepts should be

useful into the millimeter-wave region where it becomes

difficult to measure phase by other techniques. The complete calibration process can be controlled by a programmable calculator or small computer.

Accuracy of the six-port measurements is determined

primarily by the linearity of the detectors. Bolometricor thermoelectric-type power detectors would give greater

accuracy than that achieved in our experiment, but that

INSERTION

POINT

OF FIG.

REFERENCE

PLANE

Note: Six-port versus ANA.

Fig. 9. Adding a directional coupler to the setup in Fig. 2 to make

complex reflection coefficient measurements. -30-
m IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. MTT-23, NO. 12, DECEMBER 1975

would increase the measurement time somewhat. Another

approach to increased accuracy would be to model the

diodes and mathematically correct for their nonlinearity

with the computer. This latter approach is presently

under investigation.

ACKNOWLEDGMENT

The authors wish to thank C. M. Allred for assistance

in working out the self-calibration techniques. They also wish to thank G. F. Engen for his helpful discussions

throughout the project.

REFERENCES

;[1) G. F. Engen and C. A. Hoer, "Application of an arbitrary 6-port

junction to power-measurement problems," IEEE Trans. Instrum. Meas. {1972 Conferecne on Precision Electromagnetic

Measurements), vol. IM-21, pp. 470-174, Nov. 1972.

[2] C. A. Hoer and G. F. Engen, "Analysis of a six-port junction

for measuring v, i, a, b, z, r, and phase," presented at the Proc. IMEKO Symp. Acquisition and Processing of Measurement Data for Automation, Dresden, Germany, June 17-23, 1973.

[31 C. M. Allred and C. H. Manney, "Self-calibration of complex

ratio measuring systems," presented at the Proc. IMEKO Symp.

Acquisition and Processing of Measurement Data for Automation, Dresden, Germany, June 17-23, 1973.

[4] S. B. Cohn and N. P. Weinhouse, "An automatic microwave

phase measurement system," Microwave J., vol. 7, pp. 49-56, Feb. 1964.

[5) R. A. Hachborn, "An automatic network analyzer system,"

Microwave J., vol. 11, pp. 45-62, May 1968.

[6J G. F. Engen, "Calibration technique for automated network

analyzers with application to adaptor evaluation," IEEE Trans. Microwave Theory Tech. (Part II of Two Parts), vol. MTT-22,

pp. 1255-1260, Dec. 1974.

[7] , "Calibration of an arbitrary six-port junction for measure- ment of active and passive circuit parameters," IEEE Trans.

Instrum. Meas. {Special Issue on 1973 EEMTIC and IM Symposium), vol. IM-22, pp. 295-299, Dec. 1973.

-31-

APPENDIX B

CONTROL COMMANDS USED IN THE COMPUTER

OPERATING PROGRAM

The following tables list commands that are used in the

operating programs to control specific functions in the

microwave vector voltmeter. These commands are located

in various parts of the program listed in Appendix C. Use of these tables is intended to be an aid in understanding the program and in writing other software

routines or modifying existing routines.

IMPORTANT NOTICE

Certain commercial equipment is identified in this report.

This does not imply endorsement by the National Bureau of

Standards nor does it imply that the equipment identified

is necessarily the best available for the purpose.

-33-
Effect

Control Commands from Computer to MW

Device under Control Command

Insertion Step Out Scanner Model 1200 Write (1,*) WBYTE 47

Driver 120-1 Write (2,*) WBYTE 1

lJ V— CI 1 1L1C ^ Model 1 200 Wvnl l1 t"LCe> WBYTF 46

Driver 120-1 Write (2 *) WBYTE 1

Phase Shifter +90° Scanner Model 1200 Write (1,*) WBYTE 43

Driver 120-1 Write (2 *) WBYTE 1

Scanner Model 1200 Write (1,*) WBYTE 45

Driver 120-1 Write (2,*) WBYTE 1

Phase Shifter -90° Scanner Model 1200 Write (1,*) WBYTE 43

Driver 120-1 Write (2,*) WBYTE 1

Mode 1 1 200 Wtn L "i1 rLCp (1 *) WBYTE 44

Driver 120-1 Write (2,*) WBYTE 1

Phacp 1 lldoC Shi Jill fi fpr LCL 0° »_> V_- CL L L L1C 1- ModsX 1200 Write Cl *) WBYTE 42

Driver 120-1 Write (2 *) WBYTE 1

Owl LLIlca ^5 4j JLdlUlc L MnH p 1 1 1UUC J_ 1 200 nilUC (1 *) WBYTE 41

Driver 120-1 Write WBYTE 1

Switches 2, 4, 5, to S Scanner Model 1200 Write (1,*) WBYTE 40

Driver 120-1 Write (2,*) WBYTE 1

Switches 1, 3, 6, 7 to C Scanner Model 1200 Write (1,*) WBYTE 39

Driver 120-1 Write (2 WBYTE 1

Switches 1, 3, 6, 7 to M Scanner Model 1200 Write (1,*) WBYTE 38

Driver 120-1 Write (2,*) WBYTE 1

-34-
Effect

Control Commands from Computer to MW

Device under Control Command

Test Atten: 0 db Driver 120-1 Write (2,*) WBYTE (<J> or l);

1 db ii ii ii ii „ (2 or 3);

2 db " " 'it -. ii " (4 or 5);

3 db ii n " (6 or 7);

4 db ii ii " (8 or 9);

5 db ii ii " (10 or ID

6 db i; ii " (12 or 13)

7 db ii ii " (14 or 15)

8 db ti ii " (16 or 17)

9 db ii ii " (18 or 19)

10 db ii it " (20 or 21)

11 db it ti 11 (22 or 23)

12 db ti ti " (24 or 25)

13 db it ti " (26 or 27)

14 db ii ii " (28 or 29)

15 db it ti " (30 or 31)

Reference

Atten: 5 db ti ii it ii ,: (32 or 33)

10 db it ti it ii " (64 or 65)

15 db ii ii ii it " (96 or 97)

-35-
Control Commands from Computer to MVV

Effect Device under Control Command

Isolators to o-12 GHz Scanner Model 1200 Write (1 ) WBYTE 31;

Driver 1 on 1 120-1 Write (2

JU \

) T TT* T 7 m1—

1

WBYTE 1;

Scanner Model 1200 Write (1 ) WBYTE 26;

Driver 1 0 a 1 120-1 Write (2 ) WBYTE 1; Scanner Model 1 OAA 1200 Write (1 ) WBYTE 25

;

Driver 120-1 Write / O J> \J T TT> TTrpT WBYTE

Scanner Model 1 O A A 1200 Write / 1 (1 X 1 WBYTE 22;

Driver 120-1 Write (2 WBYTE l;

Isolators to 4-o GHz Scanner Model 1 OAA 1200 Write (1 A- \ WBYTE O A • 30/

Driver ion 1 120-1 Write / O \£ " ) WBYTE If

Scanner Model 1 OAA lzOO Write (1 •A- \ 75 1 WBYTE on* 29/

Driver 120-1 Write f O(2 A- \

1 WBYTE 1/

Scanner Model 1 O A A 1Z00- 1 Write ( T \1. 1 Wdi lb 24/

Driver T OA T 120-1 Write f O (2 75 J T TT> T7 T"i T? WBYTE 1/

Scanner Model T OAA 1200-1 Write (1 WBYTE O O • 23/

Driver 120-1 Write (2 *) WBYTE l;

Isolators to 2-4 GHz Scanner Model 1 0 a a 1200-1 Write (1 •A- \ 75 J WBYTE O A30;

Driver 1 0 a 1 120-1 Write / O(2 75 1 T TT) X7T1 Ti WBYTE 1

;

Scanner Model 1 O A A 1200-•1 Write (1 ) WBYTE O O 28;

Driver 1 O A 1 120-1 Write / O (2 ) T TT1 T 7 rp T-i WBYTE 1;

Scanner Model 1200-•1 Write (1 ) WBYTE O / 24;

Driver 120-1 Write (2. ) T T It X 7 mT"1 WBYTE 1;

Scanner Model 1200-1 Write (1

JU \

) WBYTE 22

;

Driver 120-1 Write (2 . *) WBYTE 1;

Isolators to . 5-2 GHz Scanner Model 1200 Write (1< X 1 WBYTE O 1 31;

Driver 120-1 Write (2

,

) T TT) T 7mT* WBYTE i;

Scanner Model 1200 Write (lj JU \) T TT* T T mTT WBYTE O ~7 • 27;

Driver 120-1 Write (2

.

WBYTE 1

;

Scanner Model 1200 Write (1.

JU \

) T TT1 X Tm T—

>

WBYTE 25

;

Driver 120-1 Write (2

.

JU \

) T Tn T 7 mTI WBYTE 1

;

Scanner Model 1200 Write (1 j

JU \

) t Tn t rm t

-" WBYTE 23/

Driver 120-1 Write (2, tV }

T 1 1 1 T£ 7 mT-l WBYTE 1

;

Take Voltage Readings Scanner Model 1 OAA 1200 Write (1 : 75

J WBYTE c 0 • 5o / from the 5 detectors DVM Model 3500 Enter (4, *) A, B

in the MVV Scanner Model 1200 Write (1, *) WBYTE 59;

DVM Model 3500 Enter (4, *) A, B

Scanner Model 1200 Write (1, *) WBYTE 60;

DVM Model 3500 Enter (4, *) A, B

Scanner Model 1200 Write (1, *) WBYTE 61;

DVM Model 3500 Enter (4, *) A, B

Scanner Model 1200 Write (1, *) WBYTE 62;

DVM Model 3500 Enter (4, *) A, B

-36-
APPENDIX C

COMPUTER PROGRAM DESCRIPTION AND

LISTING WITH SAMPLE PRINTOUT

-37-
Appendix C

Computer program description and listing.

Equations (22) - (27) in Appendix A are solved using matrix

algebra. Before expressing these equations in matrix notation, add

a subscript j to indicate the measurement number, where j =1 ... 6

in the present calibration routine which takes six measurements.

Equation (22) of Appendix A then becomes

5

f: . = V* (LP . . - P ! . ) z . = 0

j Si j 1 j 1 1

(C-l)

Subscript i refers to the detector numbers which are relabeled 1 ...

'

in the program. The following table relates the detector number used

by the program to that shown in Figure 3 .

Table C-l

Computer Number Figure 3

1 P 3 a \a 1 2

2 P 5 a aj + a 2 | 2

3 P 8 a | a

i

+ ja 2 |

2

4 P6 ot [ a

i

ja 2 | 2

5 P7 a | a 1 * 2 | 2

In matrix notation (C-l) becomes

fLPn - Pi 1 LP 12 - P; 2

L f,

LP 1 5 " Pi Zl

_LP 6 i - 6 1 LP 62 - P£6 2 LP 6 5 P^6 5.

(C-2)

-38-
Since L and are complex numbers, all matrices in (C-2) are complex.

Let L = Lj + jL 2 and = x^ + jy^ where L l5 L2 , and x_^ and are real

numbers. Write (C-2) as

F

q

= [P + jQ] [X + jY] (C-3)

where is a complex matrix but P, Q, X, and Y are real matrices;

LiPn - Hi ... L1P15 - Pi L 2? P-t 1 1 L 2 P 1 5

P = , Q

= (C-4)

LlP61 ~ P61 ••• LlP65 ~ P66 5 _L,2P6 1 ••• L2P6 5_

Xl

X = , Y = (C-5)

X5 Y5

The P and Q matrices can be written

P = LiO - I Q = L 2 0 (C-6)

Where the 0 matrix contains the data with the step out , and the I matrix

contains the data with the step "in" (3 dB inserted)

.

1 1 Pii ... PI

I = (C-7)

6 1 6 5 ?6 1 ... ?66 5

The program first takes the data to fill in the 0 and I matrices.

It then asks for an estimate of L (approximately -3 dB and 45 degrees)

from which it calculates Li and L 2 • The P and Q matrices in (C-4) are then calculated.

-39-
Initial estimates of the z^ are obtained by solving (C-l) using the

estimated value of L. Since any one of the z^ can be set equal to 1, we choose to set z 5 = 1 + jO since this tends to simplify the mathematics.

Equation (C-l) then becomes

4

L

i=l

(LP. . - P! .) z. = -(LP._ - P' )

In matrix notation this becomes

LP„ r

1 1

•

•

.. LP llf - P

r

l k Zl Lp i5 - p

r 1 5

•

- P

r

6 1

* •• LP 6 ,

•

- P

Z k _Lp 6 5 - P

' r

6 5

(C-8)

(C-9)

Let N, Z, and R be the three complex matrices in (C-9) so that (C-9) becomes

NZ = R (C-10)

Note that N is identical to P + jQ if the last column of P + jQ is deleted.

The column matrix R is the negative of the last column of P + jQ. Since N is

not a square matrix, it cannot be inverted. To solve (C-10), first premultiply by N transpose to get

N

1 NZ = NT R

Since N

T N is a square matrix, it can be inverted to give

Z = (N T N)~ 1 N

T R

(C-ll)

(C-12)

The elements of Z are only estimates of the z^ since in general L used

in C-9 is not known. The correct values of the z^ are obtained by using

the estimates in equation (23) of Appendix A.

-40-
Adding a subscript j to (23) of Appendix A gives

9f

.

f. = f . J 03

4 9f

dZ. l dL

1=1 l

AL = 0 (C-13)

The sum in (C-13) is from 1 to 4 since z 5 = 1 + jO.

notation (C-13) becomes

In matrix

9fj 5f j aZi 9z?9f i 9f

i

3z_ 3L

(C-14)

f Ofi 5f 6 9f

6

:Z; Bz 2

3f 6

- _ oZ i+ 9fs

9L J

where from (24) and (25) of Appendix A

of . J- = LP -Pi. (C-15)

9z. ji ji

9f . 5

IT = S z i

pji <c-i 6)

1=1

Let F , M, and 1Z be the three complex matrices in (C-14) so that (C-14)

becomes

-F = MAZ

o (C-17)

Substituting (C-15) and (C-16) in (C-14) shows that M is identical to

P + jO except for the last column which contains the 9f_./9L. These terms

are calculated from (C-16) which can be written

1=1

-41-
or

ill

3L 1

1

. P 1 5 xi + jyi

3L 61 . . P 6 5 X5 + jY5

Therefore M is obtained by substituting the complex column matrix

(C-20) in column 5 of the P + jQ matrix.

Initial estimates of z. to use in calculating F and M are obtained

l b

o from (C-12). With these estimates, F and M can be calculated so that

o (C-17) can be solved for AZ. The solution is

The elements of AZ are used to correct the estimated values of and L;

(C-19)

0 [X + jY] (C-20)

AZ = -(M T M) 1 M

T F (C-21)

new z. = old z. + Az

.

l 11

new L = old L + AL

(C-22)

(C-23)

The iteration is now repeated, calculating a new P and Q matrix using the new

L, and calculating a new F^ and M matrix using the new z^. Then (C-21) is

solved to get a new AZ . The iteration continues until ALj < 10 . Usually

ALi will be less than 10 6 after four iterations.

Equation (19) of Appendix A is also solved using matrix algebra, but no iteration is required. Adding a subscript j to indicate the measurement number

as before, that equation becomes

i=l

w. (p. . - p: . ) = o (C-24)

-42-
For an ideal seven-port junction, all of the w_^ = 0 except for the w corresponding to P 3 in figure 3. Since P 3 is on channel #1, we choose Wj = 1

in the program. Therefore (C-24) becomes

i=2

w. (P. . - P! .) = P! - P.

i Ji Ji Ji Ji (C-25)

which can be written

P12 - p; 2 P13 - p{ 3 ... P15 - Plsl

Lp 62 - p 62 Pes " Pes J Lw5_

W2 "Ph - P 1

1

LPei - PgiJ

(C-26)

or simply

DW = C

whose solution is

W = (D TD) 1 D

T C

(C-27)

(C-28)

-43-
Program Listing

100

lie

1 15

1 16 129

130

148

150

160

170

130

1 90

200

210

220

2 .: M 240

250

260

270

2S0

290

300

310

329

3 3 0 340

350

3 6 0 370

380

390

400

410

428

43S

PRINT " SAM TAPE #1, FILE 6> REVISED 7 MAY 1976" REN .5-12 GHZ M I C ROW AVE VECTOR VOLT HFTFR CAI T BRAT KIN MEASUREMENT PROGRAM

BUT WITH OPT 10 ADDED >]>GC5>53jHE5j5]fRC5]

> J> UC 6 3» ]» XC 5 1»-Yf 51 > Mt 7

Range constants for DVM

REM SAME AS F REM

H I M fl[ 6 6 ] > BE 6 > 6 ] > CC 6 , 5 ] , DC 6 > 5 ] , EC 5 , 5 ] , FL DIM 116)5]? Ot 6 s 5 ] > PL 6 , 5 ] > 9.1 6 j 5 ] s SC 5 i 5 1,11 DIM ME51jKC6»5]»UC6j5]

£7 = 50 Scale factor to keep determinants reasonable M[6]=-10*S7

ME 5 ] = - 160*37

ME 7 ]=ME 3 ]=~1O00*S

HEQ All angles are in degrees PRINT "PRESS COHT EXECUTE AFTER COMPLETING EACH INSTRUCTION"

PRINT

K = kl + jK2 is set to 1 + j<(j to start

K9 = <J) indicates <}> dB added to measurement channel

K5 = number of DVM readings to be averaged for each FREQUENi IN GHZ "S F73650

( 1 >*>WB'

11 = 1 K2=K9=C1=U

j..

* cr nisp

INPUT

GO SUB WRITE

GO SUB PRINT PRINT

PRINT

PRINT

PR IN

T

PR I NT PRINT ' PRINT " ENTER

"E49i

Switch in appropriate isolators

Set calibration switches to "S" (six-port) position

PRINT

PRINT

PRINT

DISP

ENTER 1 TO CALIBRATE VECTOR VOLTMETER"

ENTER 2 TO MEASURE REFERENCE RATIO"

TO MEASURE RATIO WITH TEST DEVICE INSERTED"

TO -MEASURE DVM OFFSET VOLTAGES"

TO MEASURE R0 & C" TO MONITOR REFERENCE DIODE" PRESS STOP CONT 400 WHEN DONE"

TO MEASURE STEP VALUE (L) " TO DETERMINE K FOR ABSOLUTE RATIO MEASUREMENTS

ENTER 3 ENTER 4 ENTER 5 ENTER 6

'ENTER 'ENTER "0 MEASURE f, AVERAGE RATIOS WITH TEST DEVICE INSERTED'

Instructions

. to Operator

NEXT OPERA T I 0 : ENTER 1 THRU 91 INPUT 19 GO SUB 19 OF GOTO 400

,4,J 1 10i '1080 < ik) > 39F0

,

S40.8) n • ill0 440

450

460

470

480

490

500

5 1 O 530

540

5 5 0 560

570

580

5

'-> 0 600

6 1

0

€ 2 O

6 30

6 4 0 650

6 6 0 67 0

6 S 0

6 9 0 700

710

72 0 730

740

750

760

770

780

7 9 O

! 0 0 8 1

0

8 j Q

3 3 0 840

850

8 6 0 870

880

890

8 9 5 9 8 0

REM CALIBRATING VE N=5

M=M1=6

N1=N-1

RED IN 1

1" M < N 1 > 01 M > N MAT I=2ER

MAT 0=ZER

G03UB 4300

GO SUB 4080 WRITE

GOSUB 3

1 = 1 GOSUB 3 WRITE ' GOSUB 3 WRITE >.. GOSUB 3

IjOSUB 3 WRITE ( GOSUB 3 GOSUB 3 K9=K9+6

1=4 GOSUB 3 WRITE (. GOSUB 3 1=5

GOSUB 3 WRITE < GOSUB 3 1=6

GOSUB 3 K9=0

GOSUB 3 MAT K=0

MAT L=j

1

1 WBYTE4;

'WBVTE4:

'WBYTE4J

1 > * )WB'i 350

rE44!

1 WBYTE4':

1 WEYTE42

JTOR VOL T METER

N = number of diodes used M = number of measurements made during calibration

]»KE MjH ]»LE MjN ]

Set switches to calibration mode

Read diode offset voltages

} Set phase shifter to <J)°

Take data for measurement #1

\ Set phase shifter to ±90° position

f Set phase shifter to +90°

Take data for measurement //2

Set phase shifter to -90°

Take data for measurement #3 Add 3 dB to measurement channel

Take data for measurement #4 Set phase shifter to +90°

Take data for measurement #5

Set phase shifter to 0°

Take data for measurement //6 Take out all attenuation in measurement channel

DISP "ESTIMATED RA INPUT LjT i L=10tCLv20) » L1=L*C0ST ) L2=L*SINT » DISP "USING HOW MA INPUT N N1=H-1

M=M1

riOs DB :i DEGREES ="j

L = Lj + jL2 is now a voltage ratio

Calibration data is stored in matrices K and L HY DIODES 1 ?"; N = 4 or 5 diodes can be used

-44-
9l@ REN CALCULATE THE IK. I. 920 RED I M DC M < HI 3* TC HI < M 3. PC 93U RED In OCMsNIj ICM>N3

940 GOSUB 4930

959 FOR J=l TO M 960 FOR 1=2 TO H 970 DC J a 1-1 ]=OC

J

j I 3-IE Jj I ] 980 NEXT I 990 CC Jj 1 3=lL J?. 1 3-OE J ? 1 ] 1008 NEXT J 1010 MAT T=TRN<D5

1O20 MAT P=T*D

1030 MAT P=INV<P)

1049 MAT U=T*C

1050 MAT W=P*U

1068 REDIM WEN]

1070 FOR I=H1 TO

1030 WE 1 + 1 3=WC I ] 1090 NEXT I

1 1O0,UC 1 3=1

Us Hi UCN1 IjCCMS • WE

Put calibration data in 0 and I matrices

Caculate D and C matrices

Solve for W (D TD) VC =

STEP

Change W to W =

w2

- W 5.

1110

1 li!0 1130

1 140

1150

1 160

1 170

1130

1 190

1200

1210

1220

1230

1240

1250

1260

1270

1230

1290

1300

1 3 1

0

1320

1330

1340

1350

1360

1370

1330

1390

1400

1410

1420

1430

1440

1450

1460

1470

1430

1490

1500

1510

1520

1530

1540

1550

1560

1570

1530

1590

1600

1610

1620

1630

1640

1650

REM SOLVING FOR

GOSUB 4650 Calculate initial estimate of the z. IF H=5 THEN 1160

PRINT "_ DELTA X4I> IELTA Y<I> DELTA

GOTO 1 1 1'0 PRINT " DELTA X<I) DELTA V(I) PRINT

rem _ REDIM AC M « N 3s BE M j N ] j EE Ms i 3 > F C M > 1 1 ? GC M s 1 J ? UC M 1 s VC M ] MAT A=P GOSUB 2090 Calculate F 0 = (P + jQ)(X + jY), store in E + jF MAT U=E I F 0 stored in U + jV

MAT- V=F f REDIM CCMsNIsDEMsH]

MAT C=P

^

delta l

M except for last column

Last column of M

Filling in last column of M

MAT D=Q

MAT E=0*.: MAT F=0*Y

FOR 1=1 TO M

CE I s H 3=EC I s 1 3 DC I ? N 3=FC I s 13 NEXT I RED I M AC H s M 3s BC H , M 3 s EC N sN3> FC N sN JsGC N s N J MAT A = TRH ( C 1 I MT stored in A + jB MAT B=TRN< B) » . „ . GOSUB 2090 Calculate M'M, store in E + ]F

GOSUB 2170 Calculate (M TM) -1

, store in S + jT REDIM CCMs 1 3s DC Ms 1 IjECN? i 3sFCHs 1 JsGENs 1 3 St d=v * Put F

° in 0 + jD

GOSUB 2090 REDIM CCNs13,DCh . . _( - v GOSUB 226Q

FOR 1 = 1 TO Nl -> WRITE (15. 1520>CC I - 1 35 NEXT I FOR 1=1 TO HI WRITE (15. 1520)DC Is 1 3? NEXT I WR I TE ( 1 5 ? 1 529 > CE I » 1

3

j DC N , 1

3

FORMAT 4E7.0s2Xs4E7.0s2X»2E7

PRINT

New L = old L + AL

Calculate M

T F 0 , store in E + jF

] -i Calculate -AZ = (M T M) M

T F 0 , store in C + jD

>Print -AZ

L1=L1-CEN?13 j. L2=L2-DCNslJ f X4=CCNs 1

3

MAT C=X-C i MAT D=Y-D » MAT X=C

MAT Y=D XCN3=CCNs 1 3=+l I VCN3=DCNs 1 3=0 f GOSUB 4930

IF flBS<X4)>lE-06

X4 + ALi New z

jL = old z ± + ^z

^

25 - 1 + j°

THEN 1190 If ALi > 10~ 6 then continue iterating

-45-
166@ PRINT "FREQUENC "F75 " GHZ j USING DIODES

1676 FOR 1=1 TO N 1680 PRINT 15 1690 NEXT I 1700 PRINT

1710 PRINT

1720 PRINT " UREAL L f I NRG If 1730 PRINT

1 7 4 0 L=29*LGT< S 0 R < L 1 *L 1 + L 2 * L 2

1 )

1 7 5 O P = flTH < L

.

: LI ) + 1 3 8 * < L 1 < O ) * 2 * C L

2

1

:, 60 PRINT LI • L 2 .> L ? F

'

17713 PR I NI 1780 WRITE ( 15) i?9B> "

I

- =

" 1 » 2*3»4> c 1790 FORMAT F7.0'4F10,8

1800 PRINT I ). = ".! 1810 FOR 1=1 TO N 1820 WRITE < I'm 1950>;<[ [ ]|

1830 NEXT' I 1848 PRINT

1850 PRINT "Y<I)=";

I860 FOR 1=1 TO N 1870 WRITE ( 15) 1950) YE I I? 1880 NEXT I 1890 PRINT

1906 PRINT "W(D = "i 1910 FOR 1=1 TO H 1920 WRITE (15) 1950)U[ I IS 1930 NEXT I 1940 PRINT

1950 FORMAT 5F18. ' 1-960 GOSUB 2340

IF N=5 THEN 2810

1980 DISP "RECALCULATE WITH 5 DIODE

1990 INPUT CI 2O00 IF CI =1 THEN 880

2010 M=l

2020 RED IN fit M > 1 3»Bt M- 1 b CI M.< 1 ], DC M 2030 PRINT

2040 PR I HI fVPE •RATIO 2050 PRINT "MEASUREMENT MAGNI TUBE 2060 PRINT

2070 GOSUB 2710 Measure po and C 2880 RETURN

l ( n b

y Print Constants

Calculate and print value of L for each of the 6 measurements

Li Ms l LH..H. 1 I.- ICM»N.]»Oi M » N j PHASE P'RCDBM

3 DEGREES "

O'HJ

1 00

:' 1 1 O 2128

i:i30

; j 40 150

2160

PEN

MAT

MAT

MAT

MAT

MAT MAT

RET!

g=b*d

E=A*C

E=E -G

G = B*C

F=A*B

F=F+G

JRN

f M, 'LEX MAT RICE's CA+Ji = E + JF

::i70 :130

2190

1:200 2210

2228

2230 2240

:2250

REM

MAT

MAT

MAT MAT

MA 1

; F T

INVER" G=IHV'

H = G * F S=F*H

S=E+S

S=INV> T=H*S

URN

fl COM ATRIX

"[..FX MA i R h :

' 260 < .-.IT ' - f + IF '=!: + , ID 270

280 298

200

3 1

0

320

' 2u

REM

MAT

MAI NAT

MAT- NAT

MAT RET

MULTIPLYING

G = T*F

C=S*E

C-C-G

G = T * E

D = S*F

D = D + G URN

-4b-
£348

£356

2:33

2378

£388

i: -3 2408

2410

2428

2430

2--3

2-53

2460

2478

2- E3 3- r3 £533

25:3

2528

2530

£548

2553

253 3 iz~:

2580

2590

3333

£610

3333

2648

2353

2333

2670

23 E 3 3393

MAT fl=0*X

MfiT B=0*Y

MfiT C=I*X

MfiT B=I*Y A

MfiT E=0*W

MfiT F=I*W 61

s = ^iP

6i

Ft Hi 1 3i

c =

H,H]

si

P '6i

each sun

is over

i - 1 to 5

I > * BEG p-pa>»BEG-;

+ j t yiP. a + iB

'iPi

E x.P.' + j E v.P.

_ C + jD

?

PRINT " L(I)«DB L-L< I>»BB PRINT PR=REF PORT POWER"

WRITE (15? 2450)

FORMAT 54X»"PR1-C PR2PR1-1"

_5=-5=3

FOR J=l TO \ For each measurement j calculate: E=EEJ»U

F=FEJj13

fi=HEJ. 1 HE

B=BEJ, 1 3,E C=CE J j 1 IF

B=BE J ?

1

IsF

G=fi*fi+B*B x=<fi*c+B*n:

Y=<fi*B-BsC>^G

R=SQR f X*K-5-Y*¥> L3=20*LGT-:R>

L4=L-L3

L5=L4*L4+L5

P3=HTH<Y^K)+188*€K<0>*<2*(Y >= 8>-i>

P4=P-P3

P5=P4*P4*P5

WRITE C 15 ? £698 > L3 < L4 » P3 ? P4,» E*l 886 S7 s FsE- 1 NEXT J PRINT

WRITE <15 ? £688>~ STB. DEV. ="SQR<L5^<M-1 ) > ? SQR<P5^ <H-1 >

>

FORMAT F18.4.F24.3

FORMAT 2F12.4j3F12.3j1F12.6

X + jY = p'/p = step insertion ratio

271

2

_ 3 3 1~ a 0 2740

2750

£760

2770

2788

2903

2818

£323

2838

£840

2353

2 363

Z l.z 4253 Set switches to BISP "CONNECT 58 OHM LORB TO TEST

STOP

C2=-

1

"ORT

ce=B8=e

BISP "INCIDENT POWER 01W = j INPUT PI GOSUB 4358 Reaa dlode 0UtPut voxtages

. z 2; r - Calculate voltage ratio

C8=X

I' 5=

C2=Plx-F

WRITE <15»2868>"R8 "Z»L>T» 18*LGTP1

FORHfiT F3.4»F18.3»F18.^»F12.3f Fl'2.6

Cc + jDc

• • :—ilTffiGl 2890

2900

2E-13 £9£8

2938

2940

2E53

3-33

£978

2988

HHT H=0*K

MfiT B=0*Y

MfiT E=0*H

F=EE i«ll

= E x

±

P.

- z Vl

x

ipi +

>"i pi

x=ae i j i i-F-ee i Y=Bt 1 • 1 3^F-B8 » X + jY = p Z=SORi X*X+Y*Y > *K

1

L=28*LGT<:Z)

Fi=10*LGT<C2*F>

T=flTN i Y'X ) + 1 86* < K< 8 >*(2*'

K = Kl + jK2 = l + jO

;=li:r= red fcr = ':=:3ute raci:

-easur&rer. . s

" —7——

3018 BISP "SET DEVICE TO REFERENCE VALUE"

3028 STOP

3030 I=D=1

3840 GOSUB 4358 *ea<i diode output voltages

3850 GOSUB 2888 Calculate voltage ratio

3060 R=Z 3070 S=L Store results in &, S, & P 3080 P=T

3090 WRITE Q5j 28683 "REFERENCE RAT 1 0

"

R.« L » F « F

1

2133 --J-

-47-
!1 10 1120

J 1 36

S 1 49

S150

Si 60

SI 70

SI 30

S 1 30

S200

5210

REM MEASURING RRTIQ HUH TEST DEVICE INSERTED

ITEM OR SET DEVICE'

Read diode output voltages

Calculate voltage ratio

MSP "INSERT TEST

STOP

I=D=1

GO SUB 4356

GO SUB 2880

P1=T -P P1=P 1+360*

GOTO 3210

WRITE (15 j 2860) "TEST RflTlO WR I TE (15) 2360 >

" I NSERT I ON RAT 1 0

* RETURN

(PK-1S0; :pi>180:

L • T s F

1

'Rs L-S) PI s Fl 3230 REM DETERMINE K=K1+J*K2 FOR ABSOLUTE RATIO MEASUREMENTS

3240 DISP "APPLY SAME SIGNAL TO BOTH PORTS"

3250 STOP

3260 GOSUB 4250 Set switches to measurement mode 3270 K1=I=D=1

3280 l<2 = 0 3290 GOSUB 4350 Read diode output voltages

3300 GOSUB 2880 Calculate voltage ratio 3310 K 1=1/2 Kl + jK2 = K

3 336 WRITE (if 860) "K "K1)-LjK2)F1

RETURN

3

•-• g fl REM SUB PL ilJTINE TO RIJI- •1 SWITCH DRIVER

3 360 WAIT 50

3 3 7 8 WRITE (2, WBVTEK9+1

!

3 "! I*! f*1 WAIT 50

~; Q fl RETURN i REM MEASl IRING STEP VALUE AFTER CALIBRATION

1 -' d 1 1 = 1

H- 1_ U GOSUB 3540 Measure diode voltages with step "out , step in

i> 4 o y GOSUB 23: 10 Calculate voltage ratio for step out.

-• A A Ci o h- h y R=Z

3 450 S=L

j 4 ti y F-T Store results in R, S, P, E. 3470

3480

E = F MAT 0=1

j ^ Q fl GOSUB 28: :m Calculate voltage ratio for step "in"

~; ^ fl fl P1=T-P

3510 Pl=Pl+360*>: (PK-180)- ;pi>180) > WRITE (15)2 860 )

" STEP RAT 1 0 ( L ) " Z/R , L-S ) P 1 . F

1

cr .- r f _ 1 3 j j y RETURN

"-' L:;

, J. LTH REM SUBRiJUT I NE SETS S IEP OUT GETS VOLTAGES- : :ET STEP IN- GETS „

i n i i' Qf i- 3 5 5 0 WRITE (1 WBYTE47)

| 3 5 6 0 D=l Set step "out"

3 5 7 U

5 y y b U U b i -3 j B GOSUB 4350 Read diode outputs, store in 0 matrix

3 5 9 0 WRITE (1 WBYTE46)

3600

8 6 1 y

I) = 2 nriSHR 33 | Set step "in" GOSUB 4350 Read diode outputs, store in I matrix

3 6 3 0 RETURN

J 6 4 U REM SWIT :h IN ISOLATO ?S FOR CHOSEN FREQUENCY

3 6 5 U IF F7/8 MIEN 3730

3: 6 6 O IF F7<2 I'M EN 3738

3670 IF F7>4 THEN 3838

3680 H6=28

3 6 9 0 N5=30 For 2 < f < 4 3 7 0 0 N7=24

3 7 1

0

3720

3730

GOTO 3B7

N5=31

3 3740 N6=26 For 8 < f < 12 3750 N7 = 25

3 7 6 0 3770 GOTO 387 0 3780 N5=31

3790 N6 = 27 33O0 N7 = 25 For 0.5 < f < 2 3310

3820 GOTO 3870

H5 = 30

3340

3858

N6 = 29

N7=24

For 4 < f < 8 3860 ~\ WRITE (1 ) NB i TENS 5 GOSUB 33 50

3890 WRITE (1 > W B Y T E N 6 ! 3 9 0 0 GOSUB 33 50 . Set isolator switches

3910 WRITE (1 JWBYTEN7)

3920

3930

GOSUB 33 WRITE (1 50 'WBYTEHS;

3 9 4 0 GOSUB 33 56

3 9 5 0 RETURN >

-48-
3968 REN NHHITQR D I OLE #1

3970 DISP ' MEASUREMENT a • OR

3930 INPUT J 3990 GOSUE J OF 4350? 4380

4000 1=1

4010 WRITE (If *)HBYTE63^Ii

4020 ENTER C4»*)RfB

4030 B=B*MC fi 3 4040 DISP "V AT POSITION"

I

4050 WRIT 1000

4060 GOTO 4020

- -9~

0

z ~-~ - N

! AL I BRAT I ON < 2 >

"

?

Set switches to measurement or calibration mode

Note: Change I to monitor a diode other than #1

Connect output of diode #1 to DVM

Read DVM range code (A) and digits (B) Multiply B by proper range constant

Repeat readings until stop is pressed

4030 REN SUBROUTINE TO READ DIODE OFFSET VOLTAGES

4090 DISP "TURN POWER OFF" • 4180 STOP

4110 MAT R=ZF - Set all offset voltage readings to zero 4120 FIXED 1 4130 FOR J=l TO N 4140 WRITE <1»*>NB*Y* TES3-J5 Connect output of diode #J to DVM

4150 WRIT 50

4160 GOSUB 4470 Read diode offset voltage

4170 R[.J] = B 4180 DISP "DIODE" J 5 "OFFSET ="B*iE+06'S7 Display offset in microvolts

4190 WHIT 508

4208 NEXT J 4218 DISP "SET POWER LEVEL TO START"

4220 STOP

4230 STANDARD

-140 F.E— •

4260

4270

4230

REN SET SWITCHES TO MEASUREMENT NODE

K9=32

WRITE a**>WBYTE38;

GOSUB 3358

43S0 REM SET SWITCHES TO CALIBRATION MODE

4310 K9=0

4328 WRITE a,*>WBYTE39;

4330 GOSUB 3356

434J RETUE

4350 REN READ DIODE OUTPUT

4360 FOR J=l TO N 4370 WRITE (1j*>WBYTE63-J;

43S0 WAIT 150

4390 GOSUB 4470

44O0 IF D=2 THEN 4440

4418 OCIf J]=B

4428 NEXT J

4430 GOTO. 4460

4440 iCI 5 J]=B

4450 NEXT J

4460 RETURN

•/UL ! Hbtb

Connect output of diode --'J to DVM

Read DVM

Store data in 0 matrix if D = 1, or in I matrix if D = 0.

4470 REN READ DVM K5 TINE

4430 ENTER (4f*>fifB

4490 B1=B*NCR]

4500 ENTER (4j*>H»B

4510 B=B*N[ A ] 4520 IF HBS<B><lE-05 THEN 4563

4530 IF ABSO-B-Bi >,-B.K0.Oi

4540 B1=B

4550 GOTO 4508

4560 S1=0

4570 FOR N4=l 10 5?

5

4530 ENTER (4j*>HjB

4590 WAIT 50

4680 B=B*M[ fl ] 4610 S1=S1+B

4620 NEXT N4

4630 B=S1^K5-RlJ3

4648 RETURN

h. HrERHliE

line 4020

} Program discards DVM readings until two consecutive readings agree to better than

1%'. Program then accepts next K5 readings.

Read DVM K5 times, compute average, then subtract offset voltage.

-49-
4650

4666

4680

4690

4700

4710

4720

4730

4740

4750

4760

4770

4780

4790

4: ;: 00

4810

4820

4830

4840

4850

4860

4870

4880

4890

4900

4910

4 9 2 0

REM C A L C U LATE I H 1 T I A L E S T 1 II M 7 E 0 F T H E Z ( I > F ESTIMATE OF L

R

REM

RED I M AC H , M ] j BC H , M ]

', Ft M , N 3 , Ut M > H h XI H J , YC N J GOSUB 4930 Calculate P and Q matrices

MAT A = TRN ( P

)

MAT B=TRHCQ)

R E. D I M A [ N 1 j M J j B C N 1 , M ] > C [ M i M 1 1 > D [ M * H 1 1 - E ! H 1.H1] A + jB now = N RED I H FC HI ? M 1 ] " GC N 1 > M 1 ] > HC H

1

, N 1 J > SC H 1 > N 1 J » Ti N 1 > H 1 J MAT C=TRN( A - i c + jD = N MAT D=TRH < B )

' GOSUB 3O90 Calculate N

T N, store in E + jF

GOSUB 2170 Calculate (N T N) -1

, store in S + jT

RED I M C:[ M j 11 j DC M . ] - E L H 1 , 1 ] j FC N 1 j i J j G[ N 1 j 1 J FOR 1=1 TO

CC I j 1 ]=-F'[ I s H ] C + jD = R

DC I? I ]=~Q[ I ? H ] NEXT I GOSUB 2O90 Calculate N

T R, store in E + jF

RED IN CL Nl » 1 3» DC Ml > 1 ] GOSUB £260 Calculate Z = (N T N) N

T R, store in C + jD

REDIM CC Nj 1 ]?DC N? 1 1 CC H - 1 ]=+l

DC Ns 1 ]=0

MAT X=C

MAT Y=D

REDIM HC Hj M ]? SC N ? N ] > T C N > H ] RETURN

Z5 = 1 + JO

X + jY = initial estimate of Z

4930 REM CALCULATE THE P AND * RATR~lTEl

4 940 MAT P=CL1>*0

4950 MAT P=P-I

4960 MAT Q=<L2>*0

4970 RETURN

4980

4 9 9 0

5000

5 O 1 0

5 O £ 0

5 O 3 0 504O

5050

5060

5070

5030

5 0 3 0 51.00

REM CALIBRATION DATA IN K & L MAT RICE

FOR 1=1 TO N D=I

REM DELETE NEXT LINE TO USE DIODES IN ANY ORDER

GOTO 5058

DISP " USE D I ODE #( 1 . . . 5) "

5

INPUT D FOR J=l TO M

OC Jj I ]=KC J ? D J IE J » I ]=L.C JjD 1 NEXT J NEXT I RETURN

RHNSF ERRED TO 0 I MATRICES

-50-
no

120

130

149

i£00

210

i 2 2 0

p30

1240

>27tf E80

[290

1293

1296

[300

[310

320

REM NERSUR I NG RATIO K6 TIMES N I T H TEST ICE I NSERTEL AVERAGE

DISP "INSERT TEST ITEM OR SET DEVICE"

STOP

Kb=10 Change K6 (2 to 25) to change number of times rati* is measured

RED I M GC K6 ? 1

3

j HE Kb? 1 ] FOR N4=l TO KG

GOSUB 5600 Read diode output voltages

Calculate voltage ratio

Real part of ratio stored in G matrix

5520

5530

5540

5550

5560

5570

558@

Repeat K6 times

Imaginary part of ratio stored in H matrix

Average ratio = X + jY

Calculating sum of the squares of the deviation

of individual measurements from the average

Standard deviation of X

Standard deviation of Y

IjOSUB syyy

GCH4j 1 3=X

Si=Si+X

HE H4 j 1 ]=Y

S2=S2+YNEXT M4

X = S1.-K6

| Y=S2. K6 f

FOR H4=l TO Kb

S1=X-G[ N4? 1

]

83=83+51*81

S2=Y-HEN4? 1 ] 84=84+82*82

NEXT N4

S1=SQR(S3--(K6-1 > S 2 = S Q R ( S 4 ( K 6 — 1 )

FOR H4=l TO Kb

IF ABS<GEN4? 1 ]-X

S3=S3+GE M4> 1

]

X0=X0+

1

IF RBS( HE H4j 1 3-Y

S4 = S4 + HE N4j 1

3

Y0=YO+1

NEXT N4

X=S3/X0 I Y=S4/Y0 ' Z=SQR<X*X+Y*Y>*K1 ' L=20*LGT<2)

F1=10*LGT(C2*F)

T = R T N ( Y / X ) + 1 3 0 * C X < 0 > * 1 P1=T-P

P 1 =P 1 +360* (. C P i < - 1 80 > -(PI > 1 SO )

>

WRITE < 15? 2860 > "HVG. INS. RATI 0

Z/R'j L-S j P 1 j F

1

PRINT "FOR flVERRGE OF"X0"RERL TERMS St" Y0" IMAGINARY TERMS OUT OF POSSIBLE S

RETURN ^ !

THEN 5478

Discarding any measurement whose deviation

from the average is greater than two

standard deviations

Average ratio with bad points discarded = X + jY

> = 0>-l

Calculate amplitude and

phase of insertion ratio

36M0

561

0

5620

REM READ DIODE OUTPUT

FOR J=l TO N WRITE < 1 » *>WBYTE63-Ji

WRIT 10

ENTER ( 4 ? * ) A ? B

OE I j J 3=B*M[ fl 3-RE J "J NEXT J RETURN

OLTRGES ONLY ONCE

Connect diode #J to DVM

Read DVM

Subtract offset voltage and store reading in 0 matrix

-51-
SflM TAPE #1? FILE 2? REVISED 25 APR 1976

PRESS CO NT EXECUTE AFTER COMPLETING EACH INSTRUCTION SAMPLE PRINTOUT

EH TER ENTER

ENTER

ENTER

ENTER ENTER

ENTER

ENTER

TOTO

TO MEASURE

TO MEASURE

TO MEASURE

TO MONITOR

PRESS STOP

TO MEASURE

C A L I B R A T E V E C T 0 R V 0 L T M E T E R MEASURE REFERENCE RATIO

RATIO RUTH TEST DEVICE

D'v'M OFFSET VOLTAGES

RO REFERENCE DIODE

CO NT 409 WHEN DONE

STEP VALUE CD

K FOR ABSOLUTE RATIO

INSERTED

TO DETERMINE

-DELTA X C I >

MEASUREMENTS

DELTA Y< I >; DELTA L 2E-04 IE -04 3E-05 -4E--04 5E-04 7E-04 IE- 04 5E-05

-8E 08 2E-07 2E-07 5E--08 -6.E-08 IE 07 4E-09 --5E-0E FREQUFNC Y = 3. 39 GHZ; l ISING DIODES 1 2 3 4

L REAL - L ( IMAGINARY:' LCDB) PC DEGREES)

O. 691393772 0. 504685579 -2. 1015005 40. 00314672

T = 1 3 4 5 X C I ) = -0.0557 -0 . 9527 0.0162 1.0000

Y C I > = -O. 0424 1 . 0257 -0.6448 0.0000

W C I ) = 1 . 0000 - O. 0O76 0.0067 0.8046

L £ I > ? D D L--LC I ) :'DB PCD) D EG P-PC I ) ) DEG PR = REF PORT POWER

PR1 "C PR 2 /PR 1-1 0909 -0. 0106 40.038 -0.827 -11. 235 8 . 00O145

OS 12 -0. O203 40.054 -0.051 -10. 690 -0 . 888894

0S95 -0 . 0 1 20 40 „ 1 Ufc! -0 . 1 05 1 0

.

975 -0 . 8 0 0 1 3

1

1179 0. 0164 39.762 0.241 10. 980 0 . 088125

127S 0 . 0 2 6 3 39.952 0.051 10. 784 0 . 880288

1339 0 . 0324 39.962 0.841 11. 195 -0 . 800197

STL, DEV. = a. 0231 8. 124 -he Lift ;- DELTA YC I

) --- --- DELTA L

5E- 03 -4E-02 -2E -02 4E-02 2 E - O :; : 5 E - 0 2 - 4 E - 0 2 - 9 E - 0 3 1

E

-03 3E-03

7E -65 3E-04 6E--05 -5E--04 3E-05 ~7E 84 2E - 04 IE -04 1 E-04 2E-04

4E- 96 -4E-05 -1E-05 6E-05 -IE 06 9E-05 -4E-05 2E- 05 8E -08 2E-87

FREQUENi: :Y = 3 .99 GHZ? USING DIODES 1 2 3 4

L C REAL :< Lc IMRGINftRY) LCDB) PC DEGREES;

8.-69265 138.8 0. 501276445 -2. 1 15015992 39. 7531794

:; c i

)

: Y CI):

W C I ) L C

I

-2.1

-2. 1 -2. 1 -2. 1 -2. 1 -2.1

1 0. 1006

0, 0606

1 . 0O88

) ) DB

168

157

136

159

144

140

-0. 1301

0 . 0528

0. 0435

L L •: I > DB

8. 88 i8

O. 0086

-8. 0014

0 . 0009

-0 , Mill) 6

"

" 0 . 0810

'40

'41

'f.9

0.2557

0. 6144

0. 8366

P-PC I

1 ., 0000

0. 0000

0. 0471 DEG

0.01 3 0.012

0. 007

-0. 016

0. 026

•-0.028

PR=REF

PRl/'C

1 1 . 286

10.

11.

1 1

.

1 0 , -11:

736

0 1 8 028

758

244

PORT

pr;

0. -0,

-0,

0,

0,

... g

POWER

-PR 1 1 080136

880154

000071

000022

888234

888136

STD. DEV. TYPE MEASUREMENT0. 0010

RATIO--

MAGNITUDE DB

8.81

8

PHASE

DEGREE?

PRCDBM) PR2/PR1-1

Ry • 0 . 0022 037 -126. 0. 000 Attenu. REFERENCE RflTIO 0. 7 4 79 523 138. 0. 080 Test ( INSERTION RATIO 0 . 9 9 9 9 - 0 , 001 8. 04 8, 001 0 INSERTION RATI 0 0 , 3315 5 9 2 6

,

-8 005 10 INSERTION RATIO 0. 1 03J 1

9

;6 42 0 002 20 INSERTION RATIO 0 . 8323 6^6 8 6 7 -0 004 30 INSERT I OH RATIO 0 8188 - 23 325 10 65 ' 0 005 40 INSERTION RAT 1 0 0. 0 O 3 5' -49 23 2 5 34 .... 0 006 50 INSERTION RATIO 0- 0012 -58 3 3 5 41 9 7 -0 007 60 INSERTION RATIO ' 8803 -70 144 107 36 -O 007 70 STEP RATIO CL) 0 7 7 8 0 181 48 28 -0 007 0 881681 0 STEP RATIO CL) 0 7335 119 39 88 -0 009 0 000O27 10 STEP RATIO CL.:' 0 7 8 8 7 150 39 93 -0 010 -0 000017 20 STEP RATIO CL.) O 7 7' 8 0 181 48 29 -0 009 8 000054 30 STEP RATIO a.) 0 3 c 3 8 -T 688 4 1 14 8 012 -8 000024 40 STEP RATIO CL

)

0 7612 369 46 98 -0 011 0 000309 50 STEP RATIO CD 0 331 1 -

1

687 6

1

74 -0.813 0 008297 60

-52-
APPENDIX D

INTERFACE CABLE PIN CONNECTIONS

These tables list pin connections for the interface cables

indicated in figure 1 (page 2) . The tables can be found at

the rear of the chassis of each unit indicated. A brief

description of the signal present at those pins is given to

aid in understanding or troubleshooting.

-53-
Monitor Labs

Model 1200A Scanner

To MVV

Board Channel Pin No

,

Switch Pin No Function

No 2 10 B

2 10 E

2 11 D

2 11 C

2 12 J

2 12 H

2 13 N

2 13 M

2 14 T

2 14 S

2 15 X

2 15 W

2 16 V

2 16 Y

2 17 R

2 17 U

2 18 L

2 18 P

2 19 F

2 19 K

3 20 B

3 20 E

3 21 D

3 21 C

J 22 J

3 22 H

3 23 N

3 23 M

3 24 T

3 24 S

3 25 X

3 25 w

3 26 V

3 26 Y

3 27 R

3 27 U

3 28 L

3 '28 P

3 29 F

3 29 K

step

step

(J) shifter

(f> shifter

cf) shifter

(J) shifter

2, 4, 5

2, 4, 5

1, 3, 6, 7

1, 3, 6, 7

Isolators (1

n ii & 2)

ii n Isolator 3

2 Com

1

Com

1

Com

9& Com

1

Com

2 Com

2 Com

1

Com

2 Com

1

Com

1

Com

2 Com

2 Com

1

Com

2 Com

1 Com

1

Com

2 Com

2 Com

1

Com

Step out

Common

Step in

Common

+90

-90

Thru hybrid

Thru Coax

Cal. Diodes

Cal. 6-port

Calibrate

Measure

1- 2, 8-12 GHz

2-4, 4-8 GHz

4-8 GHz

2-4 GHz

1-2 GHz

8-12 GHz

1- 2, 8-12 GHz

2-4, 4-8 GHz

4-8, 1-2 GHz

8-12, 2-4 GHz

-54-
Weinschel Switch Driver

Model 120-1

Output Data Connector

To MW

Pin Connection on device

fin I

Pin 20

Pin 3

Pin 21

Pin 4

Pin 22

Pin 5

Pin 23

Pin 6

Pin 24

Pin 7

Pin 25

Pin 8

Pin 26

Pin 1

Pin 19

+ on 1 db Step in Test Channel

- on 1 db Step

+ on 2 dB Step

on 2 dB Step

+ on 4 dB Step

on 4 dB Step

+ on 8 dB Step

on 8 dB Step

+ on 5 dB Step in Reference Channel

on 5 dB Step

+ on 10 dB Step

- on 10 dB Step

Terminal strip (Not used)

Terminal strip (Not used)

Monitor Labs Scanner Pin 4 (J2 Boards 2 & 3)

Monitor Labs Scanner Pin 2 (J2 Boards 2 & 3)

it ii

ii ii

ii ii

-55-
Interface connections from Data Precision Model 3500 DVM

to HP computer interface cable 11203A BCD Interface

Data Precision

Model 3500

Connector Pin #

Information

Direction

Hewlett Packard

11203A Interface

Wire #

Comments on description

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

968

907

96

90

1

N.C.

906

95

9

2

913

N.C.

N.C.

967

912

902

91

5

925

901

957

968

ground

Digit 9 "8" (LSD)

Digit 9 "4"

Digit 9 "2"

Digit 9 "1"

Digit 8

Digit 8

Digit 8

Digit 8

"4"

1

1 2 •

•

Mill

1000 V Range to Exp. "5'

Flag from Read Output (Invert Flag'

5th digit "8" MSD

5th digit "4"

5th digit "2 M

5th digit "1"

4th digit "1" 1/2 digit (1 or (f>)

ground

915 - 97 +5 volts to Exp. "4*

-56-
Data Precision Information Hewlett-Packard

Model 3500 Direction 11203A Interface Comments on description

Connector Pin # Wire #

A « » 968 ground

B *- 98 10 volt range to Function "4"

C 908 Digit 6 "8 M

D 93 Digit 6 "4"

E ; *~ 7 Digit 6 "2"

F 4 Digit 6 "1"

H *~ 92 1 volt range to Function "2"

J 958 Control 1 to Enable

K N.C.

L N.C.

M N.C.

N — 905 Digit 7 "8"

P *~ 94 Digit 7 "4"

R 8 Digit 7 "2"

S 3 Digit 7 "1"

T *- cj) 100 volt Range to Exp "1"

U N.C.

V N.C.

W N.C.

X — 6 100 mv Range to Function "1"

Y >~ 916 Overload to Exp. sign

Z 968 ground

Ground: 903; 908; 917; 918; 923; 924; 926; 927; 928;

934; 935; 936; 937; 938; 946; 947; 948; 956.

-57-
Monitor Labs To

Model 1200

Scanner

Connector J2

Data Precision

Model 3500

DVM

Rear Panel Input Connectors

Pin 2 High

Pin 4 — —** Low

Pin 3 Guard

Weinschel Switch Driver To Monitor Labs

Model 120-1 Model 1200 Scanner

Connector Pin No. Pin No. on J2 (Boards 2 and 3)

Pin 1 - — Pin 4

Pin 19 — + Pin 2

-58-
HP 11202 Connections to Monitor Labs Scanner

Model 1200 HP 11202 Interface

Pin Connections

1 -« Output "4" Orange

2 + Output "2" Red

3 -< Output "0" Blue

4 Output "1" Brown

5 - » Ground

6 * » Ground

7 Output "8" (Green)

8 Output "16" (Yellow)

I > Ground

16 )

22 -* ^ Ground

21 (98) Control (Cntrl) line (pin H on 11202)

All other on 11202 - short outputs to inp uts

pins open (1-1, 2-2, etc.), short flag to Cntrl

-59-
HP 11202A Interface

Unit to HP 9830

To Weinschel Switch Driver

Model 120-1

Pins 16-

15-

14-

13-

12-

11-

10-

oH-

-T (Jumper)

-S

»R

-?N

-M

>LX

Pin 3 of UIc

U — V

Pin 11 (Control Pin 1

12 (Control Pin 2

13 (Control Pin 3

14 (Control Pin 4

15 (Control Pin 5

16 (Control Pin 6

17 (Control Pin 7

18 (Control Pin 8

9 Strobe

27 Signal ground

-60-
APPENDIX E

DIAGNOSTIC PROGRAM LISTING WITH

SAMPLE PRINTOUTS

This appendix contains a listing of the diagnostic program stored

on file 4 of the MW cassette tape.

Three separate tasks can be selected when using program. They

are

:

1. Measure step repeatability

2. Measure diode linearity

3. Monitor source stability.

The program was written to be an aid for setting up the system and

for troubleshooting. Remarks have been added to the program listing to

explain the functions of the program statements.

-61-
100 PRINT " SAM TAPE #1) FILE 4> REVISED 27 flPIIL 1976"

110 REM DIAGNOSTIC ROUTINES FOR MICROWAVE V FT: TOR VP I TMFTFR

120 DIM MC 7 ] ! U[ 1 6 j 5

]

> I C 1

6

, 5 3 > RL 4 ] j VC 4 ] ISO MC6]=- 10

) 140 MC5]=- 100 > DVM range constants 156 M[7]=M[3]=~1000 ) 160 K9 = 0 K9 = 0 indicates 0 dB added to measurement channel 170 MAT C= ZER

ISO MAT R= ZER

190 MAT 0 = ZER

£00 MAT 1 = ZER

210 DISP 11 FREQ. IN GHZ"j

£20 INPUT F7 £30 PRINT "FREQ ="F7'i GHZ" £40 PRINT

£50 GOSUB 1510 Switch in appropriate isolators

£60 PRINT " ENTER 1 TO MEASURE STEP REPEATABILITY"

£ 7 8 PRINT "ENTER £ TO MEASURE DIODE LINEARITY"

£ 8 @ PRINT "ENTER 3 TO MONITOR SOURCE STABILITY"

£ 9 0 PRINT

3 0 0 DISP " TASK"

!

3 1

0

INPUT I 3 £ 0 GOSUB I OF 840? 850) £080

3 3 0 GOTO 3O0

340 REM SL BROUTINE TO MEASURE" STEP REPEFlTAB I L I TV 35W

360

GOTO 4 DISP " 10TURN OFF POWER";

3 7 0 STOP

3 8 0 GOSUB 2000 Measure diode offset voltages

390 DISP " TURN ON POWER"

!

400 STOP

410 GOSUB 430 Choose which diode to monitor

420 GOTO 5 70

430 DISP "MONITOR WHICH DIODE

440 INPUT Ji 450

460 PRINT

PRINT "DIODE NO. "JI 470 PRINT

480 J=J1-1 Set attenuation in measurement channel to zero

4 9 0 K9=@

5 O O K2=39

510 GOSUB ,830 } Set switches to calibration mode 520 K2=4i

5 3 O GOSUB 1330 1 Set switches to calibrate diodes

540 1:2=47 550 GOSUB 1830 1 Set step out 560 RETURN

579 PRINT -

. 0t - . 04". . AO " i 5 8 0 PRINT TAB35 " +.02". + .04'; +.06"."

5 9 0 PRINT

6 O O WRITE ' 15,610'

6 1 0 FORMAT 5Xh"SIGMAh '." 620 \ 1 = 1 6 3 O N=5

640 GOSUB 1SO0 Measure step ratio N times, compute average and std.

6 5 O AO = A AO = initial average 660 WRITE (15; 670>N> AO 670 FORMAT F3. O) £4X) " AO =" ) Fl

1

. 6 j 2 ? > F c . 4 680 GOSUB 1 3 0 O Measure step ratio N times again

6 9 0 WRITE ' 15) 70O 'N; 700 FORMAT F3.0

7 1

0

A=(A-A0) • AO* 100 Compute % deviation from initial average 7£0 IF fl<- 0.001 THEN 760 > 730 IF fl>£ .001 THEN 780

740 PRINT TflB32"*"TflB675 y Plot deviations

750 GOTO i 90

760 PRINT TfiB(32 + 500*A;' , " * " THE 32) "

. " T A B 6 7

)

770 GOTO ; 90

7 8 0 PRINT TAB32" . "TAB(3£+500*A )"*"TflB6?5 ^

799 WRITE ( 15) 800 >G 800 FORMAT F7.4

8 1

0

IF BBS ( A ) O. 05 THEN 640 If deviation > .05%, compute new initial average 828 K1=K1+1

830 IP Kl< 20 THEN 680 Repeat measurement 20 times 840 RETURN

-62-
5

TlIh

T

0fI POt|R

R

f

UR£

" I0 " LIHEflRITY

Measure diode offset voltages

POWER"

;

Set switches to calibration mode

Set switches to calibrate diodes

'2.3.4,5

RATIO VOLTS RATIO VOLTS RATIO VOLTS

860 DISP

870 STOP

880 GOSUB 2608

890 DISP TURN ON

900 STOP

910 N=5

920 K2=39

930 GOSUB 1830 ! 940 K2=41 I 950 GOSUB 1830 j 960 PRINT

970 WRITE (15 5 980>"DIODE NO

930 FORMAT F6,8j3F16.0

990 PRINT " RATIO VOLTS

1000 FOR K9=30 TO 2 STEP -2

1010 D=l

1020 K2=47 I 1030 GOSUB 1830 ' 1040 GOSUB 1170

1050 K2=46 i 1060 D=2 [ 1079 GOSUB 1830 ) 1089 GOSUB 1170

1090 FOR J=l TO 4

1100 V[J]=-OU r, J]

1110 Rt J 3=0t K9-- 2? J II K9 '2? J 3 1120 NEXT J

1130 WRITE < 15s 1146) K9^2? * DE " Rt i 3 j V1 1 3 ? Rt 2 3 ? V[ 2 3 « Rt 3 lV vt 3 II s Rt 4 1? Vt 4

]

1140 FORMAT F4.0>F8.3jF8i4»F8.3jF8.4»F8.3»F3.4»F8.3«F8.4

1150 NEXT K9^-^ ' 1170 REM SUBROUTINE TG SCAN AND READ DIODE VOLTAGES

1188 3=0

1190 FOR J=l TO 4

1200 WRITE <1,*>WBYTE62

1210 GOSUB 1390

1220 A=B

1230 IF H=2 THEN 1270

1240 OtK9^2«J3=A

1250 NEXT J 1260 RETURN

1270 ICK9 2,_lj=A

1280 NEXT J

1290 RETURN

Set step out Read all diodes

Set step in

Read all diodes

Connect diode #J + 1 to DVM

Read DVM

Store data in 0 matrix if D = 1 for step out

or in 1 matrix if D = 2 for step in

1 380

1310

1320

1330

1340

1350

1360

1370

1380

1390

1400

1410

1420

1430

1448

1458

1460

1470

1480

1490

1500

r=r . S=G2=0

FOR 1=1 to

K2=47

GOSUB 1830

WRITE (1 r- GOSUB 1390

V1=B

K2=46

GOSUB

WRITE

GOSUB 1898

V2=B

i •VERfiGE & % STB, DE'=

\ Set step out

\ Read diode «J + 1 five tines

J Set step in

IBVTE62--I5 ) , . Read diode - : J + 1 five times

V = ratio of step out to step in

L,£=G2+VT2

NEXT I A=S'H

G=SQR(ABSUG2-A^

G=10ti-G-H

RETURN

,' N Compute average and % standard deviation

-63-
1510 rem subroutine to set I sol h tors to. the correct frequency range

1529 IF F?>8 THEN 1608

1530 IF F7<2 THEN 1650

1548 IF F7>4 THEN 1700

1550 N6=28

1568 N5=30

1570 N7=24

1530 H8=22

1598 GOTO 1740

1600 N5=31

1610 N6=26

1620 N7=25

1630 N8=22

1640 GOTO 1740

1650 N5=31

1660 N6=27

1670 N7=25

1680 N8=23

1698 GOTO 1748

1708 N5=30

1718 N6=29

1720 N7=24

1730 N8=23

1740 WRITE U»*)WBYTEN5i

1750 GO SUB 1858

1760 WRITE <1>*)WBYTEN65

1770 GO SUB 1858

1780 WRITE (. 1 > *)WBYTEN*7

5

1790 GOSUB 1850

1800 WRITE ( 1 » *)WBYTEN85

1810 GOSUB 1S50

1328 RETURN , 1838 REM SUB ROUTINE TO RUI 1848 WRITE ( 1 > * ) WBYTEK2 J 1850 WHIT 50

I860 WRITE <2>*>WBYTEK9+1S

1870 WHIT 58 1388 RETURN

WITCH DRIVER

1898 REN SUBROUTINE TO READ HI OLE 1988 B=S

1918 ENTER <4>*>A1>B4

1928 FOR K=l TO 5 1930 ENTER C 4 . * > H

1

5 E 1 1940 WHIT 50

1950 B2 = B1*N[ HI l-r.L J ] I960 B=B+B2

1970 NEXT K 1980 B=B---5 1990 RETURN

,'OLTHGES

Subtract offset from each DVM reading

2 O O O REM S U B R 0 U T I HE T 0 M E Fl S U R E 0 F F S E T V 0 1 TAGE

S

ieie MAT C=2ER

2028 FOR J=l TO 4 2030 WRITE <1>*)WBYTE62--Jj Connect diode #J + 1 to DVM 2040 GOSUB 1890 Read DVM 2O50 CCJ]=B

2060 NEXT J 2070 RETURN

:838 2090

2100

2110

2120

2130

2140

2142

2144

2150

2160

2178

2175

21S0 2190

2192

2193

2194

2196

2197

2198 2280

2210

2220

o

"• 2230

REM MEASURING A VOLT ALE UN THE DATA PRECISION 3500 DVM £, PLOTTING

REM OR DISPLAYING DEVIATIONS FROM THAT VOLTAGE WITH TIME. GOSUB 430 Monitor which diode? WRITE ( 1 ; *)WBYTE62-J j Connect diode #J + 1 to DVM FOR 1=1 TO 6 ) ENTER (4>*)R1jV / Discard six DVM readings NEXT I ) DISP "ENTER 1>2jOR3 FOP . 05* „5"., OR <rj%"\ INPUT S7

DISP " PRINK 1) OR DISPLAYC 2) "!

Choose range of deviations

as +0.05%, ±0.57., or +5% INPUT K IF K = 2 THEN 2580

GOTO S7 OF 2180) 2193 j 2197 PRINT " -.06*. -.04* -.82". PRINT TAB 35" +.02* +.04* +, GOTO 2280 PRINT " -.6* -.4* -.2"; PRINT THB35 " +.2* +i4* +. GOTO 2200 PRINT " -6.0* -4.8* -2.8*

PRINT TAB35" +2.8* +4.0* +h.0*

PRINT " N * * * * WRITE ( 15- 2220)

FORMAT 5X) "SIGMA, *" S7= 1 0t- ( S7- 1

') ^7 * s now a sca le factor N=10

HO

HO

HU

-0-

Input 1 to plot deviations on printer

Input 2 to display deviations

Headings for different ranges

S7 - 1 for ±0.05% range

S7 =• 10 for ±0.5% range

S7 = 100 for +5.0% range

-64-
1240

£258

i'270

1290

1300

1310 2320

?33@

1340

1358

1360

1370 1330

1390

1400

1416 1420

1430

?440

GOSUB

R@=fi WRITE FQRMRT

N=10 WRITE FORMAT

H=100*

IF fl<- IF H>0 PRINT

GOTO PRINT

GOTO PRINT

WRITE FORMAT

IF H B

S

GOTO 2 END

i4j0 Read DVM AO = initial average 2276) Ns R0? G

0 5 24:*; ? " R0 =

" j F 1 1 . 6 j 27X .- FS . 4 2450 Read DVM U5j2310)N5

F3.0

H-H0}.- (H0*S7> Compute % deviation from initial average and divide by S7 0.001 THEN 2370

.001 THEN 2390

TRB32"*"TRB67;

400

TflB(32+500*fl) j

,, *"TflB32 ! ". " TABS7 ! I 400

TRB32" . "TflB(32+500*fi> "*"TRB67j J

<15j2410)G

F7.4

: AH 0,05 THEN 2290/ „ . . . oog > If deviation is greater than the chosen

J range, compute new initial average

Plot deviation

1450 1460

1470

1480 1490

1500

1510

1520

1530

1540

!550 1560

;570

REM READ DVM N TIMES? COMPUTE AVE RAGE

FOR 1=1 TO H ENTER (4!*>A1;B

V=B*M[fll ] S=S+V

nextV

A=S.-N G=SQR< <U2-R*S ).'; H-l>

)

G=100*G--"fl RETURN

£UiL

X STD. DE'

:' 5 8 0 1590

1600

1605

1610

1620

1630 1640

1650

1660

1670 1680

1690

1700 1710 720

1:730 :740

:750

1760

1770

1780 790

REM SAME AS ABOVE EXCEPT DISPLAYING INSTEAD OF PLOTTING

K = 0 N=5

57=10*037-1 > See line 2225 GOSUB 2450 Read DVM A0=A AO = initial average WR I TE (. 1 5 j 2646 ) N , R0 j " T I ME S I HCE LAST REZERO = " K*0 . 867 , G FORMAT F3.0;5X5 ,, H0 =" j Fl 1 . 6 j 3X> FS. 0 j " SEC. SIGMA =",FS.4

K=0

9 ENTER • 4 , - > R i , B ) 9 A=B*M[ fll ] I 0 Rrl00*<fl-H0>.'(R0*S7>'

Read DVM one time, compute

% deviation from initial average, divided by S7 IF A< -0.0O1 THEN 2730

IF R>0.001 THEN 2750

DISF TAB 16"*"

GOTO 2760

D I SP TAB C 1 6+5O0*A )

, "* " TAB 1 6

:

GOTO 2760

DISP TRB16" . "TAB 1

: 16+500*R j "

K=K+1

IF ABSCAX0.04 THEN 2660 f If deviation is greater than the chosen GOTO 2blo

:ND

Display deviation

range, compute new initial average

isa 0 1810

1820

1830

1840

1350

I860 1870

1830

1890

1 9 0 0 1919

1920

1930

1940

1950

I960 1970

1 9 8 0 1990

1000

DIODE

iD]

REM PLOTTING STEP RATIOS

DISP "PLOT (0=N8 1=YEK)

INPUT S IF S=0 THEN 2990 FIXED 4 3=0

FOR D=l TO 4 S=S+0[ 15.< H] IL 1 NEXT D S=S.-4 FOR D=l TO 4 PRINT "FOR -DIODE "D+l PRINT "STEP RATIO ="TRB18j S-0. 04 PRINT "

! | 4-++-T-++H FOR. J=15 TO 1 STEP -1 PRINT OC J ? D j < TAB ( 60+ 1 000* >. OC I'D] ;L NEXT J PRINT

NEXT D STANDARD

RETURN

PAGE

Compute average step ratio at lowest power setting. Use this average to determine scale.

HB

DJScale = .05%/division

4- + -r+ I -t- + + + + + + + + ! + + + +

Plot ratios

-65-
SflM TAPE #1? FILE 4j REVISED 27 HP I II iiu

FREQ = 0.5 GHZ

Sample Printout

T&slt #1, Step Repeatability

ENTER 1 TO MEASURE STEP REPEATABILITY

ENTER 2 TO MEASURE DIODE LINEARITY

ENTER 3 TO MONITOR SOURCE STABILITY

DIODE NO

-.Ufa 04". 02'. H6

3- + . 02" + .04". + . @6*i

HO 71822:

SIGMA

6. 6639

6. 0063

8. 8067

8. 8053

8. 0020

8. 0041

0.0041

0. 8832

8. 0Ub . 8.8055

8. 084'

0. 0055

8. 8019

8 , 0859

8. 8822

8. 8850

8 . 0835

0, 8832

8. 0025

-66-
Sample Printout

Taak 2, Diode Linearity

IP REPEATABILITY

jDE LINEARITY

. lB CE STA6ILIT i

4 5 RATIO RATIO VOLTS RATIO VOLTS

.743 0.001

1 . 729 0.0011 0.0620 1 .741 0. 001

1.738 0.0014

0.6025 ."45 0.0017 1.747 0.0018

1.746 0.0630 . 742 0.0021 1 . 739 0.0022

0.0640 . 0.0027 1 . 739 0.0023

6

c y . vu-*o 1 .743 •J. 00^. 1 • r 4U 0 . 0034 046 1 .741 0.0043 1 . 737 O. 0044

. .741 0.0051 1 • 737 0. 0054

0'4 6.6106 .739 0. 0069 8.8872

0.8121 .741 0. O0S3 U738 0.0086

0.6154 .734 0. 0106 1.730 O.Olll

.731 0.0128 1 . 727 8.8133

.723 0. 0166 K718 0.0173

.719 0.0198 1.712 0. 0207

.767 0.0251 1.698 0.0263

1 . 7393

6.661.

+ + I +++++

>•!«»»•• I »«!*+ + I + •» I f

*

0.01

STEP R»1 -0.8811 -8.6814

-0.0810

-0.0022

-0.0826

-0.80:14 -0.0044

-0.8054

-0.8872

-0.8636

-8.61 1

-•.em

-0.81? j -6.8267

-0.826 ~i

1 . 7393

i + + + + + + ! + + + + +

-67-
SAM TAPE #1h FILE 4 ? REVISED 27 API IE 1976

FREQ = 0.5 GHZ

E N T E R 1 T 0 H E A S U R E S T E P R E P E Fl T fl B I L. I T

'

ENTER 2 TO MEASURE DIODE LINEARITY

ENTER 3 TO MONITOR SOURCE STAB I L I TV

Sample Printout

Task 3, Source Stability

DIODE NO.

Q6"-;; 64! . 0id".

.. .J * .. AO =

AO +. 02": 0 % - - - *• - -u „ 07 *'

' i 40

*

*

+ , id 4"

-* + . Ob*-- *

AO 0 079585

,,,

,,, -68-

SIGMAj

-0 * 0048

-0. 0099

-0.0911

-O. 0014

-0 , 0096

-0. 0009

0019

0090

0O34

O033

0 0 1 9 0023

001 1 0O24

0019

0017

0026

001 1 0. 0015

0. 0014

0063

0007

0017

0019

0025

00 1 5 0. 0049

0 . 0006

0014

001 1 O026

0019

001 1 001 1 0042

0016

OOZ'' 0019

0071

0014

001 1 0 0 3 4 0106

0032

0O26

0O25

0O2O

0O26

0016

002 1 00 1 I 00

4

001 1 0016

0 , OO 1

1

0 .0019

, ., 0029

h , 0049

0 . 0 O O 9

- O ,, O 0 O 9

-0

~0

-0

-0

-0

0

-0 "0

-0

-0

- 0

-0

-0.

-0.

-0.

-0,

0. -0i

0 « -0.O. -0.

O. -0.

-0.

•-0 » 0. -O.

-0.

- O . - 0 . 0. -0.

- 0 . 0.

- O . -0. -0.

-0.

0.

... H

-0.

0.0 .
NBS-114A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 76-844

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

A MICROWAVE VECTOR VOLTMETER SYSTEM

5. Publication Date August 1976

6. Performing Organization Code

276.03

7' AUTi8Mxi C. Roe and Cletus A. Hoer 8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 2763433

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Department of the Air Force

USAF School of Aerospace Medicine (USAFSAM)

Brooks Air Force Base, Texas 78235

13. Type of Report & Period Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

This report presents a system description and operating

procedure for a vector voltmeter system which covers the

frequency range .5 to 12 GHz. The design is based upon

a seven-port junction where phase and amplitude information is obtained using only power detectors. The system

is computer controlled and self-calibrating for ratio

measurements

.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by senuqolons) Amplitude; computer controlled; diode detectors;

microWave measurements; phase angle; self-calibration;

seven-port junction; vector voltmeter.

18. AVAILABILITY [XXUnlimited 19. SECURITY CLASS

(THIS REPORT)

21. NO. OF PAGES

I For Official Distribution. Do Not Release to NTIS

UNCL ASSIFIED 68

1 Order From Sup. of Doc, U.S. Government Printing Office Washington. D.C. 20402. SD Cat. No. C13

20. SECURITY CLASS

(THIS PAGE)

22. Price

k# y! Order From National Technical Information Service (NTIS) TM

Springfield, Virginia 22151 UNCLASSIFIED $4.50

USCOMM-DC 29042-P74

USCOMH LRL