NBSIR 74-371

BROADBAND PULSED/CW CALIBRATION SIGNAL STANDARD

FOR FIELD INTENSITY METER (FIM] RECEIVERS

hilip A. Simpson

Electromagnetics Division

Institute for Basic Standards

National Bureau of Standards

Boulder, Colorado 80302

June 1974

Final Report

Prepared for:

Calibration Coordination Group

Army/Navy/Air Force

Attn. Mr. M.L. Fruechtenicht

Redstone Arsenal, Alabama 35809

CCG 72-70

NBSIR 74-371

BROADBAND PULSED/CW CALIBRATION SIGNAL STANDARD

FOR FIELD INTENSITY METER (FIM) RECEIVERS

Philip A. Simpson

Electromagnetics Division

Institute for Basic Standards

National Bureau of Standards

Boulder, Colorado 80302

June 1974

Final Report

Prepared for:

Calibration Coordination Group

Army/Navy/Air Force

Attn. Mr. M.L. Fruechtenicht

Redstone Arsenal, Alabama 35809

CCG 72-70

u s DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretan/

NATIONAL BUREAU OF STANDARDS Richard W Roberts Director

CONTENTS

Page

1. INTRODUCTION 1

2 . CHAEIACTERISTICS OF RECEIVERS 2 2.1. Detection Modes. 2 2.2. Bandwidth of Receivers 2 2.3. Narrowband Signals 3 2.4. Broadband Random Signals., 3 2.5. Broadband Impulsive Signals 3 2.6. Calibration of Receivers 4 2.7. VSWR Effects on Receiver Accuracy 4 3. STANDARD SIGNAL SYSTEM 5 3.1. Theory 5 3.2. Description of Standard Signal System. 6 3.2.1. Voltage Tuned Oscillator 9 3.2.2. YIG-Tuned Multiplier 9 3.2.3. YIG-Locking Loop 9 3.2.4. RF Burst Generating Section 9 3.2.5. Monitor and Attenuator Section .11

3.2.6. Pulse Trigger Circuit 11

3.2.7. Avalanche Pulser and Bias Circuits 15

3.2.8. VTO Tuning and Metering Circuits 15

3.2.9. Filter Switching Circuit for 1 to 2 GHz,

1-Watt Signal 15

3.2.10. YIG Bias Supply 15

3.3. Calibration of Standard Signal System 21

3.3.1. Calibration of Power Monitor 21

3.3.2. Calibration of Pulse Duration 21

3.3.3. Calibration of Step Attenuator 21

3.4. Experimental Checks of Spectral Intensity 22

3.5. Sample Problem of Calibrating a Receiver 23

3.6. Maintenance 24

4. ACCURACY OF STANDARD SIGNAL SYSTEM 25

4.1. Uncertainty of Gain Calibrations 25

4.2. Accuracy of Bandwidth Measurements 26

5. FUTURE WORK 26

5.1. Improvements to Prototype Standard Signal System 26

5.2. Second Generation Standard Signal System 27

6 . ACKNOWLEDGMENT 27

7. REFERENCES 28

iii
Contents (Continued)

Page

APPENDIX A. CONSTANT VOLTAGE GENERATOR FOR THE STANDARD

SIGNAL SYSTEM 29

APPENDIX B. CALIBRATION CHARTS AND TABLES 31

APPENDIX C. MAINTENANCE 41

LIST OF FIGURES

Fig. 1. Time and frequency domain characteristics of a pulsed rf signal 5 Fig. 2. Photograph of Standard Signal System for calibrating

Field Intensity Meter receivers 7 Fig. 3. Block diagram of Standard Signal System 8 Fig. 4. Amplifier for locking YIG tuned multiplier to VTO 10

Fig. 5. Photographs of incoherent rf bursts made on a sampling oscilloscope. Horizontal scale = 5 ns/div.

(a) 1 mW, 1.5 GHz; (b) 1 mW, 3 GHz; (c) 1 mW, 6 GHz;

(d) 0.1 mW, 11 GHz 12

Fig. 6. Block diagram of circuit for generating coherent

rf bursts 13

Fig. 7. Pulse trigger circuit 14

Fig. 8. Avalanche pulser circuit 16

Fig. 9. Circuit for mixing bias and switching signals

to diode switches 17

Fig. 10. VTO tuning circuit 18

Fig. 11. Low pass filter switching circuit 19

Fig. 12. YIG bias supply circuit 20

Fig. 13. Circuit used for calculating components of

the TT pad 29

Fig. 14. Monitor reading in milliwatts for 1 milliwatt

reference level 30

Fig. 15. Wiring diagram for power supply chassis 44

Fig. 16. Power supply interlock circuit for protecting

VTO and 1-watt amplifier 45

Fig. 17. Wiring diagram for frequency tuning chassis 46

Fig. 18. Wiring diagram of remote head 47

iv
ABSTRACT

This report describes the constructional details and the

operation of a system for calibrating microwave field intensity

meter (FIM) receivers in the frequency range 1 to 12.4 GHz.

The system uses known levels of CW power to calibrate the

receiver, and short duration (-20 ns) rf bursts to measure

the bandwidth. An error analysis of the system is given.

Schematic drawings of various circuits in the system are provided

along with charts and tables for facilitating computations

encountered when performing calibrations.

Key words: Broadband signal generator; impulse bandwidth;

receiver bandwidth calibration; rf burst generator;

spectral intensity.

v

BROADBAND PULSED/CW CALIBRATION SIGNAL STANDARD

FOR FIELD INTENSITY METER (FIM) RECEIVERS

1. INTRODUCTION

A long standing need has existed in.DoD and elsewhere for an accurate

and convenient means of calibrating receivers in the broadband mode. For

frequencies in the VHF and even into the UHF regions methods involving the use of CW, baseband impulsive type signals, radiometric techniques have been

employed [1,2,3]. However, at frequencies above 1 GHz these techniques tend

to become ineffective or inaccurate.

For example, the spectrum of baseband signals usually begins to exhibit

an excessive roll-off in amplitude which is associated with the finite

duration of the impulse. In addition the spectrum is often complicated by

stray parasitic reactances inherent in the impulse generating elements and

their associate circuitry.

CW techniques suffer also since they do not truly represent the

conditions receivers will be subjected to when measuring broadband signals.

Furthermore, obtaining measurement data to determine the pass band

characteristics requires elaborate automatic test equipment or else can be

quite laborious. Also, the conversion from some measured bandwidth, e.g.,

3 dB, 6 dB or 20 dB, to impulse bandwidth is usually cumbersome and

complicated and quite often yields a poor approximation [4]

.

The technique described in this report employs a known rf signal

consisting of a train of evenly spaced, short-duration, rf bursts to determine the bandwidth of the receiver. It has the advantage of concentrating

most of the energy in the signal uniformly in the frequency region where

the receiver is tuned and subjecting the receiver to a broadband signal

similar to signals encountered in actual use. An additional advantage of

this technique is that the measurement is quick, accurate and, therefore,

quite convenient to make.

As originally planned, this endeavor was to develop detailed calibration

procedures for all microwave receivers in the frequency range 1 to 12.4 GHz

in the DoD inventory. By mutual agreement this objective was discarded and

an investigation into the general techniques of calibrating receivers in the

aforementioned frequency range was substituted.
2. CHARACTERISTICS OF RECEIVERS

2.1. Detection Modes

As used in this paper, the term "receiver" means a frequency selective

voltmeter used to measure the strength (or amplitude) of an unknown signal.

Two modes of detection are available in most receivers*, average and peak.

The average mode is used to measure the average value of the envelope of the

signal and is usually employed with CW signals. The peak mode measures the

maximum value of the envelope of the signal. It is usually employed when

measuring pulsed signals, because the average value is so small it is difficult to measure accurately while the peak value is often several orders of

magnitude greater than the average value.

2.2. Bandwidth of Receivers

Several different types of bandwidths are referred to when discussing . receivers. Most common in usage are the random noise bandwidth and impulse

bandwidth. The random noise bandwidth is usually approximately equal to the

3 dB points on the actual voltage response curve of the receiver. It is

often found experimentally by determining the "equivalent area" rectangle**

of the voltage squared response curve. The impulse bandwidth of a receiver is that equivalent rectangular

bandwidth which produces a measured voltage in the receiver when it is

subjected to an impulsive type signal. An equation for it is

^^imp = G,(S). ' ^ O imp

where

v.. = the maximum value of receiver transient response in volts as M

a function of time,

Gq gain of receiver expressed as a voltage ratio, and

(S)^^p = impulse strength of the signal in volts per Hz.

As pointed out by Larsen [5] , there are many definitions of impulse

strength. The definition chosen for this report is based on RMS voltages,

since this value of voltage is generally used in practice.

*Sometimes a third mode, "quasi-peak" is also available. Its response is

between that of the other two.

**An "equivalent area" rectangle is one which has the same area and peak

amplitude as the particular response curve under consideration.

2
Typical bandwidths in microwave receivers range from less than 1 kHz to

5 MHz or more. The bandwidth of the final i.f, section for all practical

purposes determines the bandwidth of the receiver. For certain types of

signals narrow bandwidths can be employed effectively, and for other types

of signals wide bandwidths have better application.

2.3. Narrowband Signals

This type of signal is defined as one which has all its energy contained

within the passband of the receiver. Some examples are CW, AM and SSB

modulated carriers, and FM. When measuring these type of signals, especially

"weak" or low amplitude ones, it is advantageous to use narrow bandwidths

so as to enhance the signal-to-noise ratio. The amplitude of narrowband

signals is expressed in volts or some submultiple, e.g., microvolts.

2.4. Broadband Random Signals

A broadband signal is one which has its energy distributed over a bandwidth greater than the passband of the receiver. A random signal has the

additional property of being composed of a large number of signals having

components of random amplitude, frequency and phase. In this type of signal

there are no clearly distinguishable pulses but rather they tend to overlap.

The most common example of a random signal is thermal noise. The measured

strength of random broadband signals is proportional to /BW and is usually

expressed in terms of an amplitude density function*. Units of measurement

are V/Hz, or some submultiple such as yV/MHz.

2.5. Broadband Impulsive Signals

Like the previous signal, this type has its energy distributed over a bandwidth greater than the passband of the receiver. However, in this type

the signal is periodic and the amplitude, frequency, and phase of the

component signals have definite fixed relationships with each other. In the

time domain, this signal is represented by one which does have clearly

distinguishable pulses. Common examples are pulse modulated rf, ignition

noise, and motor brush noise. The measured strength of this type of signal

is proportional to BW; thus to enhance signal to noise ratio of this type of

signal one would increase bandwidth (random noise is proportional to /bW) . Units of measurement are also V/Hz, or yV/MHz.

*" Spectral Intensity" is often used but is a misnomer. In all other

disciplines intensity denotes power while spectral intensity refers to

volts, the square root of power.

3
2,6. Calibration of Receivers

In order for a receiver to measure a narrowband signal correctly, only

the gain must be known. This is most easily done by applying a signal of

known amplitude to the input and noting the receiver indication.

For measuring the impulse strength, (S)imp' of broadband signals,

equation (1) indicates two factors must be known, the gain and the bandwidth. However, one cannot simply know the gain-bandwidth product for if

the receiver is calibrated with a known broadband signal and the bandwidth

changes, the gain will be unknowingly misadjusted to compensate for the

change. This in turn will cause an error when measuring narrowband signals.

The same reasoning applies if the impulse supplied by the internal calibrator

changes with time. The spectral distribution of the impulse will change

causing one again to misadjust the gain.

The technique employed at NBS [ 6] to calibrate FIM receivers is to

first set the gain of the receiver using an input signal of known amplitude.

The internal calibrator (usually an impulse generator) is then connected to

the receiver input and the meter reading is noted so that the gain may be

accurately set in the field. With the gain thus set the bandwidth of the

receiver is measured and a correction factor developed which is applied to

the nominal bandwidth associated with the receiver. This, too, is the

approach used with the Standard Signal System.

2.7. VSWR Effects on Receiver Accuracy

Receivers very often have appreciable input VSWR, 1.5 or 2. The

condition is often aggravated on the more sensitive ranges where the input

attenuators are removed from the signal path. Larsen [7] has shown that the

input impedance varies widely within the passband of the receiver, and the

point of zero phase angle and minimum VSWR do not coincide; nor does either

one necessarily occur at the frequency to which the receiver is tuned. This

mismatch problem can cause an error in setting the gain of the receiver if

it is done on a constant incident power basis since some of the power may be

reflected. A low- impedance constant voltage generator, which is unaffected

by the receiver input VSWR, would reduce errors from this source and is

desirable. Unfortunately, well characterized, low- impedance voltage sources

in this frequency range are not readily available so a constant incident

power method is used in this system. A possible means of converting this

system to a constant voltage generator using a tt pad is given in Appendix A.

4
3. STANDARD SIGNAL SYSTEM

3.1. Theory

The technique described here uses a pulsed rf signal to establish a broadband signal suitable for determining the impulse bandwidth of receivers.

A consideration of the characteristics of the spectrum of this type of signal

will be helpful. Figure 1 is a sketch of a pulsed rf signal in the time and

frequency domains.

TINE DOMAIN

FREQUENCY DOMAIN

4- er PRF

f.± f.l f.l 1-1 Vt Vt Vt

Figure 1. Time and frequency domain characteristics of a pulsed

rf signal.

The spectrum of an rf signal of frequency f^, modulated by a rectangular

baseband pulse of duration, t, and repeated at every time interval, T, is a series of lines spaced 1/T apart. To a first order approximation, the amplitude of the lines for frequencies above and below f decreases according to

sin X

a relationship where x = tt (f ± f) t. Second order effects, as disX o cussed by Reeve [8], can be neglected when a sufficient number of cycles

exist within the rf pulse. The amplitude of the lines is zero when the

quantity (f^ ± f) equals some integer multiple of 1/t .
The amplitude of the line at can be shown to be equal to V^x , and

over a frequency range near f^ where ^

- 1 the impulse bandwidth of a receiver can be determined by the following equation

^^imp = , (2) o 1

where

Vj^ = maximum response of the receiver transient as a function

of time in volts,

= gain of the receiver expressed as a voltage ratio,

= RMS voltage of the rf carrier applied to the input of the

receiver in volts, and

T = time duration of the rf burst in seconds. If the burst is not

rectangular, x is the effective rectangular time duration.

Since the impulse strength of the signal is V^x , the observed voltage, Ep

(which equals V^^/Gq) , will be V-j^x integrated over the bandwidth and can be

calculated by the following equation:

f + 5W

po 2

f BW

o 2

= Vj_xf o 2

o 2BW

= Vj^x(BW) (3)

A table of bandwidth vs. observed voltage has been derived from (3) and is

given in Appendix B. This table assumes 1 mW input power for the bands

1-2, 2-4, 4-8 GHz and 0.1 mW for the 8-12.4 GHz band.

3.2. Description of Standard Signal System

The Standard Signal System is composed of three parts. These are (1)

the power supply chassis, (2) the frequency tuning chassis, and (3) the

remote head. Also included in the system is a commercial power bridge for

monitoring the output power. The two chassis are housed in a rack, and the

remote head is connected to the frequency tuning chassis by two shielded

cables and a power cable. Figure 2 is a photograph of the system. A block

diagram of the system is shown in figure 3. The following sections describe the more important parts of the system and their function.

6
2. Photograph of Standard Signal System for

calibrating Field Intensity Meter receivers.

7
8
3.2.1. Voltage Tuned Oscillator

The voltage tuned oscillator (VTO) is located on the frequency tuning

chassis. The VTO operates over a frequency range 1 to 2 GHz with an output

greater than 50 mW. Its output is amplified to 1 watt, filtered, and

connected to the remote head by means of an RG223 cable where it is routed

through either the 1 to 2 GHz channel or to the YIG-tuned multiplier (YIG)

.

3.2.2. YIG-Tuned Multiplier

The YIG-tuned multiplier, located in the remote head, is used to

generate higher frequencies from the 1 to 2 GHz signal. The multiplication

factor of the YIG in the different frequency bands is listed below.

BAND MULT. FACTOR

1- 2 GHz out of circuit

2- 4 GHz X 2 4-8 GHz X 4 8-12.4 GHz X 7 After the YIG, the signal passes through a switch which is used to turn off

the signal so that the zero of the monitor may be checked.

3.2.3. YIG-Locking Loop

Following the switch is a 10-dB directional coupler with a diode

detector on the coupled port. The detector furnishes a dc signal to the YIG

lock circuit. This circuit (on the frequency tuning chassis) provides a correction signal to the YIG so that it will stay tuned to the precise

multiple of the VTO frequency. This allows one knob tuning of the system

making it easier to operate.

If the lock is broken, e.g., when switching ranges or first turning

on, the circuit provides a temporary ramping voltage to sweep the YIG

frequency through the region of the harmonic of the 1 to 2 GHz signal until

lock is re-established. A LED indicator on the front of the frequency tuning

chassis glows when the loop is locked. A schematic diagram of the YIG locking

circuit is shown in figure 4.

3.2.4. RF Burst Generating Section

After passing through a continuously adjustable attenuator which is

used to set the reference level of the signal on the monitor, the signal is

routed through one of the four bands listed in 3.2.2. Here it encounters

an isolator, a diode switch, and a bandpass filter. The isolators are used

to reduce the effect of the diode switches on the frequency generating

elements of the system.

9
a

O

to\

{l> r-^ Ih 1 S i|) Li-II 1—*JU—ill 3 5 """ssfs|~?sl;, 5 a=

O>o

+J

V4

Q) •H

a, •H

l-l e

0)c

+JoH

>^

D> •HUOuoH

•H

iHauH

Em

10
The commercial diode switches (all four channels) have high isolation

(>9 0 dB) and fast transition times {<5 nsec) . They are in the conducting

state with a negative voltage applied and are in the high insertion loss

state with a positive current of 100 mA applied.

The bandpass filters are used to remove harmonics of the rf frequency

and the low frequency transients caused by the switching pulse. Because the

VSWR of the filter affects the turn-off characteristic of the rf pulse, some isolation in the form of pads is provided between the switch and the filter

in the 1 to 2 GHz and 2 to 4 GHz bands, where sufficient excess powfer ihakes

this possible. Figure 5 shows photographs of the rf pulse waveforms for

each of the four ranges. - It can be seen that the two lower frequency ranges

have "cleaner" waveforms.

3.2.5. Monitor and Attenuator Section y After passing through one of the rf butst generating sections, the

signal is connected to a single common channel where it passes through

'

another 10-dB directional coupler which has ; the power bridge monitor

connected to the coupled port. The signal .jthen passes through a calibrated . step attenuator to the output connector of the remote head; ' /; The" attenuator is calibrated in steps of 1 dB up to 99 dB. This allows

setting of accurate rf levels below the reference level established by the

monitor.

3.2.6. Pulse Trigger Circuit

A pulse trigger circuit located on the frequency tu^ilng^ chassis; is used

to initiate the signal which produces the 'rf burst. The vt^figger has the ' following characteristics:^

Amplitude = 1 V triangular into 50 ohms.

Duration = 20 nsec, and ^ • PRF = 10 to 10,000 pps.

This circuit can also be operated from an external trigger source. In the

external mode the PRR is adjustable over a range of single shot to several

megahertz, which exceeds the 100 kHz maximum repetition tate of the pulser it

drives. Both modes of operation are disabled when the system supplies a CW

signal. / \ '^J' 'S \'

One common use for the external mode is generating coherent pulses. A

coherent pulse is one that is triggered at the same type of zero crossing

(positive or negative going) every time. In this way the rf carrier

maintains the same phase relationship with the envelope in each pulse. The

trigger for initiating the modulating pulse is usually derived from some

sort of countdown circuit on the carrier. A block diagram of a simple

arrangement with a sampling oscilloscope is shown in figure 6. A schematic

of the trigger circuit is shown in figure 7.

11
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en •H [2

g ^ e e rH . fO o w ^

(d ^T) c • o >

•HN \ O

CO in - w II e P <1) >H X! rH

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+J rH C fO

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(U 4J tC M C O

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a, o

to CO M o N . Cr> iH tc N 0 rH O ffi

4-> -H

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m • rH

04

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inUP

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fa

12
13
14
3.2.7. Avalanche Pulser and Bias Circuits

The avalanche pulser, located in the remote head, is connected to the

trigger circuit in the frequency tuning chassis by means of RG223 cable.

Design of the avalanche pulser is based on a circuit developed by Andrews [ 9]

.

A schematic is shown in figure 8. The circuit switches in approximately 1 nsec and supplies a -30 V pulse of 20 nsec duration. Its maximum repetition rate

is approximately 100 kHz.

The circuit diagram for mixing the negative pulse with the positive bias

current is shown in figure 9. The 39-ohm resistor when combined with the

10-ohm resistance of the diode switch bias arm forms a suitable SO-olim

termination for the switching pulse. A blocking capacitor in the avalanche

pulser prevents the dc from flowing in that circuit just as a ferrite bead

in the mixing circuit keeps the pulse out of the bias supply.

When the system is operated in the CW mode -10 volts is applied to the

bias arm which effectively turns the diode switch on.

3.2.8. VTO Tuning and Metering Circuits

The circuit diagram for supplying the tuning voltage to the VTO is

shown in figure 10. The tuning voltage varies from 0 V to 10 V. Much bypassing of the tuning voltage is required to reduce FM to insignificant

levels. This voltage is supplied also to the YIG locking loop and to a switching circuit for filters in the output of the 1 to 2 GHz, 1-watt

amplifier.

3.2.9, Filter Switching Circuit for 1 to 2 GHz, 1-Watt Signal

The switching circuit for the two filters in the output of the 1-watt,

1 to 2 GHz amplifier is shown in figure 11. flysteresis has been designed

into this circuit so that switching is done at 1300 MHz, when increasing the

frequency, and 1100 MHz when decreasing the frequency. The 1400 MHz low pass

filter is required to reduce the level of the second harmonic when operating

at the bottom end of the 1 to 2 GHz band. In the three other frequency

bands the second harmonic is effectively reduced by the action of the YIG.

3.2.10. YIG Bias Supply

Bias voltage is supplied to the YIG in order that it may multiply the

fundamental frequency efficiently. Different voltages, depending on the

harmonic number, are supplied from a low impedance source shown in

figure 12.

15
16
17
18
19
20
3.3. Calibration of Standard Signal System

Three quantities in the Standard Signal System require calibration for

proper operation. These are (1) the monitor reading, (2) the pulse duration,

and (3) the step attenuator.

3.3.1. Calibration of Pov/er Monitor

The monitor is calibrated by operating the system in the CW mode and

measuring a reference power level at the output connector. The monitor

is calibrated at 10 frequency points in each of the four bands. Reference

level for the three lower bands is 1 mW and for the 8 to 12.4 GHz band

it is 0.1 mW. A calibration chart is shown in Appendix B.

3.3.2. Calibration of Pulse Duration

The pulse duration, needed for the calculation of impulse strength

in equation (3) , is measured using a sampling oscilloscope. The scope time

base is first calibrated with a 1-GHz sine wave. The pulse duration is

determined from photographs of incoherent pulses.

It was found that the duration of the pulse within each frequency band

varied not more than ±0.1 nsec (±0.6%). The durations measured are;

1 to 2 GHz — 22.6 nsec,

2 to 4 GHz — 18.1 nsec,

4 to 8 GHz — 18.0 nsec, and

8 to 12.4 GHz — 19.5 nsec. For the monitor reference levels in 3.3.1 and using the relation

(S) . ^ = V,T imp i

= 5053.5 yV/MHz ±3% (1-2 GHz),

= 4047.3 yV/MHz ±5% (2-4 GHz),

= 4024.9 yV/MHz ±8% (4-8 GHz),

= 1378.9 yV/MHz ±8% (8-12.4 GHz).

3.3.3. Calibration of Step Attenuator

The step attenuator is calibrated at four frequencies, 1, 4, 8, and

12 GHz. Attenuation changes relative to the 0-dB position were measured.

The attenuator was then inserted in the Standard Signal System and changes

in the power output recorded in 1 dB increments up to 3 0 dB for the three

frequencies 1, 4 and 8 GHz and up to 22 dB for 12 GHz. There were relatively

small differences (-.1 dB) in the power ratio of corresponding 1-dB

steps after about 3 dB attenuation was inserted in the system. Based on this fact curves were derived using a least squares fit on the data. In

(S) imp

(S) imp

(S) imp

(S) imp

21
most cases a linear approximation was sufficient, but for some steps a slight

curvature of the attenuation vs. frequency curves required a second degree

equation. A table of attenuation vs. frequency for the different steps is

given in Appendix B.

3.4. Experimental Checks of Spectral Intensity

As an experimental verification on the calculation of spectral intensity

from the time domain data, measurements of the bandwidth of a commercial

receiver were made at frequencies where the four bands of the Standard

Signal System overlap, viz., 2 GHz, 4 GHz, and 8 GHz. While making measurements at any one of the frequencies, all factors were kept constant, and

only the frequency band of the Standard Signal System was changed. Any

differences in measured bandwidth, therefore, were attributed to relative

errors in the determination of spectral intensity. The results are given in

the following table.

.. Bandwidth Measurements on a Commercial Microwave Receiver

Standard Signal System Receiver Percent

Band

GHz

Frequency

GHz

Frequency

Band, GHz

Bandwidth

MHz

Difference

1-2 2 1-2 4.97

2-4 2 1-2 4.92 ±0.5

2-4 4 2-4.4 5.34

4-8 4 2-4.4 5.23

±1.0

4-8 8 4.4-10 4.83

8-12.4 8 4.4-10 4.60

±2.5

Manufacturer's specifications for the bandwidth and accuracy of the receiver

are Bandwidth = 5 MHz ± 10%

Accuracy = ± 3 dB

22
3.5. Sample Problem of Calibrating a Receiver

In this section an example of calibrating a receiver at one frequency

is given. This measurement was performed immediately following line 2 in

the table in section 3.4 when the receiver was switched from the 1-2 to

2-4.4 GHz band. This serves as an indication of the constancy of the

bandwidth when changing bands on the receiver.

The receiver has a 127 mm (5 in.) meter on the front with two scales,

linear 0 to 60 dByV and logarithmic 1 to 1000 yV. In addition, steps of

20, 40, and 60 dB of attenuation may be inserted in the signal path to

measure higher voltages, i.e., voltages up to 1 V. In this example, measure- ments were performed on the +20 dB step which has no attenuation in the rf

input section but 20 dB in the i-f section. As a means of increasing the

precision, a digital voltmeter was connected to a jack on the rear, labeled

Y output. This jack is in parallel with the meter and has an output of

2.25 volts for full scale meter deflection.

One other point affecting the measurement procedure is the internal

noise in the receiver. On the three higher ranges (20, 40 and 60 dB) it

amounts to approximately 19 dB above the meter zero on the 60 dB scale for

a 5 MHz nominal bandwidth but varies with time and frequency. In order to

reduce errors from this source, measurements were performed as near full

scale as possible.

The procedure for calibrating a receiver is as follows:

1. Select the voltage range, frequency band, and frequency at

which the receiver is to be calibrated. These parameters

are mentioned earlier in this section and are re-stated below.

a. voltage range 20 to 80 dByV

b. frequency band 2-4.4 GHz

c. frequency 2 GKz

2. Set the Standard Signal System to the desired frequency (CW mode)

and output level, and connect to receiver.

a. set frequency range to 2 to 4 GHz

b. set frequency to 2 GHz

c. set monitor to .115 mV'J (see fig. 14, Appendix B)

d. set output attenuator to 30 dB

e. determine from Table 2, Appendix B, the precise

attenuation, 30 dB = 29.29 dB

f. calculate calibrating voltage, 107 dByV-29.29 dB = 77.71 dByV

3. Set the receiver to the desired range and frequency

a. set attenuator to +20 dB (20 to 80 dByV)

b. set frequency band to 2.0 to 4.4 GHz

c. tune frequency to 2 GHz

23
4. Set the gain of the receiver

a. set the gain so receiver reads 77.71 dByV or the digital

voltmeter reads

(77.71-20) dB X ^-Q^^^ = 2.164 V

b. switch to "CALIBRATE" position on receiver and record

digital voltmeter reading

DVM = 1.626 V X 2^25^V " 43.36 dByV

NOTE: This reading allows one in the field to set the gain of

the instrument. It is independent of input voltage range,

hence, no addition for the +20 dB. The manufacturer

quotes this value as 43 dB ± 0.5 dB.

5 . Measure bandwidth

a. switch receiver from "CALIBRATE" to +20 dB

b. switch Standard Signal System to "PULSE"

DVM = 1.385 V

= (36.93 + 20 dByV)

= 56.93 dByV or 702.26 yV

c. To normalize the receiver response to the reference

input level (1 mW in the 2-4 GHz band) , multiply by

attenuation factor in Standard Signal System

attenuation = 29.29 dB or a voltage ratio of 29.14

signal ^ 702.26 yV X 29.14

= 20464.0 yV

d. find bandwidth in Table 1, Appendix B

in column 2, BW = 5.06 MHz

3.6. Maintenance

Detailed alignment steps for the various circuits are given at the end

of this publication in Appendix C. By following the instructions therein,

and referring to the appropriate schematic drawings, factors causing improper

operation of the system can be isolated and corrected.

The power supply chassis and the frequency tuning chassis are accessible

by removing the front panel rack screws and pulling the chassis forward out

of the cabinet on the built-in chassis slides.

The interior of the remote head is best exposed by removing the side

plates. The control wiring is reached by removing the bottom plate. Due

to the compactness of the unit it may be necessary to remove some components

in order to reach others.

24
4. ACCURACY OF STANDARD SIGNAL SYSTEM

4.1. Uncertainty of Gain Calibrations

When setting the gain of an instrument, the accuracy is dependent

primarily upon

a. the uncertainty in the CW power calibration and

b. the uncertainty in the step attenuator calibration.

The power calibration has an uncertainty at 1 GHz of 1 percent which

increases to 2 percent at 12 GHz. In the table below this fact is shown in

the 0-dB row which gives the uncertainty in dB.

The uncertainty in the attenuator calibration at a given attenuation

value does not change with frequency in the range 1 to 12.4 GHz, but does

increase with higher attenuation values. This is reflected by the values

in the boxes in the next three rows which are the sum of the power calibration and attenuator uncertainties. One should remember that rarely will

the attenuator be set to 60 dB or greater, since most gain calibrations are best made at full scale for reasons mentioned in 3.5.

It should also be kept in mind that this is an incident power system

and mismatch errors will be introduced if the im.pedance of the receiver is

appreciably different from 50 ohms.

Error in Gain Setting in dB (±)

Freq

dB ^-^GHz

Step

1-4 4-8 8 - 12.4

0 .10 .12 .15

1-60 .15 .17 .20

61-80 .33 .35 .39

81-90 .43 .45 not used

25
4.2. Accuracy of Bandwidth Measurements

Since the measurement of bandwidth basically involves comparing the

voltage of a standard 1 mW CW signal with that produced by a 1 mW peak

broadband signal, many errors cancel out. For instance, the gain setting

affects both readings by the same amount and, therefore, does not contribute

to the uncertainty. The same is true for mismatch errors. The primary source of uncertainty is errors in the measurement of t , the effective pulse duration, which determines the amplitude spectral

density. Contributing factors to this uncertainty are listed below.

a. Duration Measurement - this measurement is made on a sampling

oscilloscope. The uncertainty here is 3 percent. There is no detectable difference between results from coherent and non- coherent pulses as discussed by Reeve [10] since at these

frequencies and pulse durations the minimum number of rf cycles

in a burst is approximately 20.

sin X

b. Roll Off in Amplitude Spectral Density - due to the function

the amplitude spectral density is not constant but drops off for

wide bandwidths. Table 2 in Appendix B lists bandwidths up to

10 MHz assuming a straight linear relationship for voltage vs. bandwidth. The error due to this assumption is 0.5 percent.

c. Aberrations in Pulse Shape - as can be seen in figure 5 the turnoff of the pulse in the three higher frequency bands is not clean

but is characterized by a continuation of the signal at low

amplitude for a readily discernable time. The shape, amplitude,

and duration of this unwanted oscillation varies as the frequency

is tuned over the band and contributes to the impulse strength,

(S)^^p, in the region of the carrier. The maximum uncertainty

associated with this effect is 5 percent.

These three factors create a total uncertainty in the measurement of

bandwidth of 8.5 percent.

5. FUTURE WORK

5.1. Improvements to Prototype Standard Signal System

It is planned in the near future to correct the conditions which cause

the aberrations in pulse shape discussed in 4.2. This will be done by adding

an isolator or attenuator between the diode switch modulator and the bandpass filter. This may require reducing the output of these stages somewhat,

but measurement experience gained with the system so far indicates power

levels above -10 dBm which are needed for calibrating receivers above

100 dByV have only a minor importance. For these ranges there is so much

26
attenuation inserted in the input stages of the receiver that there is little,

if any^ difference in the gain and bandwidth measurements for this range

and the next more sensitive one. The benefit of removing 5 percent uncer- tainty in the bandwidth measurement should outweigh any disadvantages

associated with the possible loss of signal amplitude.

Something of a bigger endeavor is the designing and fabrication of a

TT pad such as described in Appendix A. This addition to the system would

provide a constant voltage source for calibrating receivers. The problem

of a constant incident power system and mismatch effects because of high

VSWR's would be eliminated. This endeavor would entail an effort lasting

approximately six months and requiring moderate funding.

5.2. Second Generation Standard Signal System

Since this effort was started three years ago advancing technology has

brought forth many new devices on the market. Some of these devices would

now greatly simplify the construction of a standard signal system. For

instance, in 1971 there was no suitable solid state oscillator in the 4 to

8 GHz range. Now there are VTO ' s in this range that will deliver as much

as 25 mW.

This means the frequency multiplication system with the YIG is no longer

required nor is the locking circuit, the 1-watt amplifier, several power

supplies, and the frequency range switching circuits.

Instead four separate remote heads could be built each with its own oscillator and rf burst generating components. Each head would be one fourth

the volume and less than one fourth the weight of the existing remote head.

Whichever head was to be used would be connected to a control chassis

which would provide the tuning voltage, power and trigger signal to the head.

The control chassis, because of less components being required, would be

approximately half the size of the present power supply chassis and frequency

tuning chassis. This new Standard Signal System would be truly compact and

convenient to use.

6 . ACKNOWLEDGMENT

I wish to thank Mr. Paul A. Hudson for the many helpful suggestions he

has given during the three years of this effort. A very special thanks is

due Arthur R. Ondrejka for the fine help he has given both of a theoretical

and practical nature. Thanks are also due Ezra Larsen and William Gans

for the help they have rendered. The major portion of the construction was done by John R. Benes and for his fine work I am very grateful. Last but

not least thanks go to Mrs. Edna Trump who did the typing of this report.

To these and all the others who aided me I express my heartfelt thanks.

27
7. REFERENCES

[I] R. B. Andrews, Jr., "An impulse spectral intensity measurement system,"

IEEE Trans., Vol. IM-15, pp. 293-303, December 1966.

[2] A. R. Ondrejka, "Development and evaluation of a solid state impulse

generator," Unpublished NBS Report, Final Report on Project CCG 69-26,

56 pages, December 1970.

[3] G. R. Reeve, "Calibration of impulse noise generators," unpublished NBS

Report.

[4] E. B. Larsen, "Calibration of receivers to measure broadband interference," NBSIR 73-335, 69 pages, September 1973, page 64.

[5] Op. cit. [4] p. 5.

[6] H. E. Taggart and J. W. Adams, "Electromagnetic interference

measurements at AFA, Fort Huachuca, Arizona," NBSIR 74-361, 69 pages,

December 1973.

[7] Op. cit. [4] p. 19.

[8] Op. cit. [3] pp. 35-37.

[9] J. R. Andrews, "A frequency calibrator for UHF using an avalanche

transistor," QST, Vol. LVI , No. 5, pp. 16-18, May 1972.

[10] Op. cit. [3] pp. 35-37.

[II] Op. cit. [4] pp. 20-23.

28
APPENDIX A. CONSTANT VOLTAGE GENERATOR FOR THE

STANDARD SIGNAL SYSTEM

A constant voltage generator (with its low source impedance) is

superior to a constant incident power source for calibrating receivers in

that the excitation applied to and actually affecting the receiver can be

determined with greater accuracy, even in the presence of sizable VSWR's.

Larsen [11] has given experimental verification of this fact at lower

frequencies

A design which employs a tt pad with 50-ohm input impedance, and 1-ohm

output impedance is given in this section. The pad closely approximates a constant voltage source. (A T pad is a constant current source.) In order

to be most effective over the frequency range of the Standard Signal System

thin film techniques should be used to fabricate the device and precision

type N connectors incorporated into the design for the input and output

interfaces. A schematic drawing of the pad is shown below.

Figure 13. Circuit used for calculating components of the tt pad.

Using the above model and the above criteria, namely, Z^^^ = 50 ohms and

Z^^^ = 1 ohm, values for Rp and Rg can be calculated for a 40 dB attenuator.

These are

Rp = 102.1 ohms

Rg = 97.0 ohms

For a load VSWR of 2:1 the input impedance is constant to 0.01 percent

or less, and the attenuation varies over the range of only +1 percent to

-1.8 percent. An incident power system with a 50-ohm output impedance,

operating into the same VSWR, can be in error by 3.5 dB. Compared to this

value the variations using the tt pad are quite minor.

29
APPENDIX B

CALIBRATION CHARTS AND TABLES
Table 1

c?'aNOWIOTH VS OBSER'^CD outpjt vcltace

BANDWIDTH 1 - Z GHZ 2 - h GHZ - 3 GHZ 3 - 12. GHZ

MHZ MICROVOLfS MICROVOLTS MICROVOLTS KICROVCLTS

{ Ref. to LRef. to (Rpf^_bQ (rSL&£^ to

1 mW input) 1 mW input) 1 mW input) 0.1 mV? inpi

n.^ Ti-^—- _

^—a-,-u a* 0 o«-o- 0.1 5Q5.'t - kQ2.5 137.9

2 10-ia •Z a 0-9^-5- Sfl5-. .0 2 ZS.^-

0.3 151o.l 121*+. 2 1207.5 ^13.7

IL. A 20 21 Sx>±S-*S 1-5.1 0 *M ^ 0.5 2S26.3 2023.6 2012. 659.'*

0^6 3n Z.Z*l -2 +2^^ 4 2'>1.3-. Q ^2 7 0.7 3D3/.3 2333.1. ZPlY 9cv*2

0*-^ ka-k Z..i 3 237-.^ 5 213,3 1103 .-t- 0. 9 45^^.2 36i^2.b 3322. ^+ 12^1.0

i-.-a sau.:'i . i-: <^-0.--tZ-*-o -* i-3z^

1. 1 555 i.9 ^.if52.0 4^27. H 1516,8

1..2- 6a6'^-.^ 4 3 56.-7 h 829 . ^ . 16-5-i*.-©

1.3 eSoj.b 5Zbl,S 5232.4 17^2,5

1.J+ _Za7.it.»3 £ 6.66 .-2 5c3't . a . 193 a.J*-

1.5 75 3G.3 6C7Q.9 6C37.4 2'Jc6.:5

Liia da ^-^-.Js UiLEL^Z 6 u 3-3-*il.— 22C a, 2-

1. 7 35 91.0 bb£0.4 6 8^,2.^ 2 34iT.l

. 90 9^ .J : . 72 &5 .1 Z 24 2^4= 2* rj_ 1.0 9631.7 7659.8 7647,+ 2619.3

^ i 0i-U./^.2: ^ ti.Q^i*-r.6^_: -B 0^: ;J . 3 ZZuJ.^

2.1 10612.4 r~4r9.3 5'Vi2,. 3 2895,5'

2jl2 11 i.lZ - 7 ^.9.uJ*_.u Q i6 5.4 . ^ 3 A^J

2.3 11623.1 9303,3 9257,3 3171 ..+ 2.. A 12i2i..>^ S 7.13 .5 9659 . 3 3 3i]

2.5 12633.6 1C118.2 10062.3 3447.2

121 3>j »± ±i 5il2.*3 LQ-464 . d 3 5 --5.. D.- 2.7 13fcH-^.5 10927.7 10567. 3 37J;2.9

2-1-5 l^i-r^.j _11.3.3Z.^_k 112X ? ,.3 3it^Q...3_,

2.9 l^o5•^.2 iJ 737.1 11672.3 09^6.7^

J3..J1_ 1.51_6J.,j 12 141.._9 12074,6 ..___4 1 36

3. 1 15661.9 1 2546.6 12h7^.3 4?.-'i',5

-3.* 2 A.bl7j..:3 12 951. .3 1237 .3. 3_ 4-^12.

3* 3 1 56"6.o J3356.0 13262.3 ^^550.

3

3_.J+ l7r.dZ..2 Jlixaii^S _J_368 4- Z.._ 46^ d., 1-

3.5 17667.3 1^4165.5 140o" . 2 4326.0

3.«_6 1 31 9 Z ^7. ±4 5_7C-,_2 . X4 4 5 9 .7 4 9 b 3.. :i- 3.7 1869b. 0 14975.0 14592.2 5101.8

3 ..a , JL9 2jL3 J> 1 5 ^ 7ii .. 7 1_5Z5 4 . Z 5 2 3.9 . 7

.

3.9 197Qi,7 1:764.4 15697.2 5377.6

- 31
Table 1 .(Continued)

3AMDWIDTH VS 03SER-;ED OUTPUT VOLTAGE •.

|

BANDWIDTH 1 - 2 GHZ 2 - it GHZ 4-6 GHZ 8 - 12.4 GHZ

MHZ MICROVOLTS MICROVOLTS MICROVOLTS MICROVOLTS

(Ref. to (Ref .

. to (Ref. to (Ref. to

1 mW input) 1 mW input) 1 mW input) 0.1 mW input)

i+. 0 2021«+ .1 16189.1 16 099 .

5515.5

i+.l 20713.^ 16593.9 16502.2 5653.3

k,Z 2122^ .a 16993.6 1690i+ . 7 5701.2

if . 3 2173 0.1 17^+03.3 17307.

5929.1

k*k 22235.5 17 S Oo .

.11^1 — —W—V _w—V 17 7 0 9.7 6 n 6 7 . f! k» 5 227if 0 ,3 ie212.o loil2.2 6204.9

• 6 232^0.2 \ f 617 .5 18514.7 63i.2. a

it. 7 2 3751.3 19022.2 18917 .2 64fc0.7

u , 6 2^+25 b,~J loif 27 .0 19 319.6 6616.5

k . 9 2^*762.2 195 31.7 19 722.1 6756.4

5. Q 2 52 or. 6 2C2 36.J+ 20 12h .

6 8 94.3

5.1 25772.9 206^+1,2 20527.1 7032.2

5.2 2627 - .3 210^*5 . 9 2092?.

7170.

5.3 267 3 3.5 21^+50.6 21333.1 73U8.

5. ^ 2 72';?.0 ri 3 3 5 » 3 2173-f . 6 7 4-5.9

5,5 2779'^.

22260.1 22137.1 75 8 3.8

5. 5 2 6 2 j 9 . 7 £^ o ^ • 3 22 539.6 772i>

5.7 266 0 5.1 2 30 69.5 229^*2.1 7 85 9.5

5 . 8 2^^310 .£+ 23H7i*.3 2 3 3i+^t . 6 7 99 7.4

5.9 29813.3 23879.0 237^+7 .1 6135.3

o , 0 30321.1 2^+263.7 2itlif9.6 8273.2

c. 1 3ns 2c .5 2f4o8a.5 2it552.0 8411.

6.2 31331.^ 25093.2 24954.5 6549.

6.3 316 3 7.2 25^97.9 25357.0 3 6 i 6 . 8

b»k 323^2.5 25902.6 2575 J.

8 82 4.

6.5 328^^7.26 3 07. i» 26162.

8962^6

6 . 6 333^1 ,2 26 7 12.

2656i+ . 5 <^ 1 0 .

6.7 3 3 6 5 •: .5 27116.3 26 967.0 9233.4

6 .

3^3o 3 .

27321.6 2 7 36 9.937 6.3

6.9 3^869.3 27926.3 Z777Z, 0 0514.2

7 1> Q 3537u .6 2f! 331.0 2 5174_. 5 _9_c.5 2.J)

7,1 3 56 Sn .3 2?=735.7 25577,

97e9.9

7.2 363 8^'. .3 291^+0.5 2 3 979.5 . _ 992_7.S. _ 7.3 2b3i*5.2 2 9 362.

1 0 0 0 5 . 7

7.^ 3 7o 3^} .a .29Jit9.9 2978'+ . 5 . ii}_2.'L3_..6._ ' 7.5 3 7901.^ 30 3 5if.7 30186.9 • 10341.5

7.6 ^3_8^p_C._7 30 759.^ 3 0,569._-f„ 1.G4I_9„..4

7.7 38912.1 31l6if .1 3 0 991.9 10617,3

7,5 3 9^+1 7. 't 31563.8 3139-T.4

7.9 39922.0 . 31':)73.6 31796.9 10693.

32
Table i (Continued)

T4NDWIDTH VS UBS£R»/£D OUTPUT i/OLTAGE

BANDWIDTH 1 - C b!l£ 2 - ^ GHZ i» - 6 GHZ b - lZ,k GHZ

nlOKUVUL I

i

(Ref. to

niUKUVULIi

(Ref. to

HICROVGLTS

(Ref. to

A. n

1 mW input)

jUU^2 .: . 1

1 mW input)

22 3 78 .3

1 mW input)

^2199 . ^

0.1 mW input;

11 0 3 0 J 9

e.i

1 ^ . £

7 n "7 Q 7 n 32601.

9

3 -3004 .

—^ nfc >^ y-r—w-' 'jf — —

iiias.d

e. 3

—t f- ^ «

w> o :5 c » 33hOo .

9

3 3 0 . if l|i+4^»5

1 1 5 c 2 c S • 5 ^^ H -+ u i • -J 3 *2ii . 9

3 H U 1 ^4 • H 11720*3

1 i '3 • 2

fc.

. C d 1 1 » +

.•''•S 16.1

35016.9

3 5 if 1 ^ 3

11996,

1

1 2 3 . 0 5. 9

q. n

t» Zj. O 7 A V

'f-^t+ri 1. . 7

O L. b <^ U * J 35621 .

3 6 2 2 -+ » 3

12271,9

1 2 0 9 . 3

9. i o. ?

H ^ 3 U / • U J r o J U n o 77 2 35.

n

3o 62c . ci 7 C 2 :>

,

12547,7

9. 3

q. ^

/i A G O 7 7 37431.3

3 7 5 . 12623. i»

9.5 ii A n fi ^ /j H o iJ u :) 0

*? >4 /i O O ^. C 4 H y • c 33 23d .

5

13099.2 i t ^2^7 .

1

9.7

q. 8

39236.

7

_35oc3j>*.

39041.

S

, 1 3 5 7 5 • 0

1 1 2> q

9.9

! n. n 3 9ai+6.3 136^0.3

33
APPENDIX B

- Table 2 CftLCULATION OF OUTPUT ATTENUATOR STEPS

GHz 1 dB 2 dB 3 dB 4 dB 5 dB 6 dB 7 dB 8 dB 9 dB 10 dB 1.0 0.81 1 . 8<« 2.85 3.93 l*.8<t 5.88 6.88 8.0 7 8.85 ^.1*7 2.0 0.81 1 .8^ 2.85 3.93 i«.8& 5.88 6.88 8.0 7 8.90 9.1*9 3.0 0.31 1 .61* 2.85 3.93 1* .88 5.88 &.&6 8.07 8.93 9.50

it.O 0 .81 1 .aw 2 . 85 3.93 li.gO 5.88 6.88 8.0 7 8.96 9.52

5.0 0.81 1 .81* 2 . 85 3.93 '*.92 5. 88 6.88 8.07 8.99 9.5(* 6.0 0 .81 1 .8k 2. 85 3.93 '.9'* 5.88 6.88 8.0 7 9.01 9.56

7.0 0.81 1 .di« 2.65 3.93 i» .96 5.88 6.88 8.07 9.02 9.58

6.0 0 .81 1 . 8i« 2.85 3.93 '*.98 5.88 6.88 8.07 9.03 9.59

9.0 0.81 1 .81* 2. 85 3.93 5.00 5.88 6.88 8.07 9.02 9.61

10.0 0.31 1 .81* 2 . 85 3.93 5.02 5.88 6.88 8.07 9.02 9.63

11.0 0 . 31 1 . 31* 2.85 3.93 5.01* 5.88 6.88 8.07 9.00 9.65

12.0 0.31 1 .81* 2. 85 3.93 5.0b 5.88 6.88 8.0 7 8.98 9.67

12.'* 0 .81 1 .8^ 2.85 3.93 5.07 5.88 6.86 8.07 8.97 9.67

CALCULATION OF OUTPUT ATTENUATOR STEPS

1.2.

3.

i*. 5.6,

7.

8.9. 1&.

Ilia.

12.

10 dB

9 .1*7 9.1*9 .50 ,52

,51* ,56

,58 ,59

,61 ,63

,65 9.67

9.67

11 dB 10 .28 10.30

10.32

10.31. 10.35

10.37

10.39

10.1*1 10.1.3

10.1.1* 10.1*6

10.1*8 10.1*9

12 dB 1.3 1 1.33

1.35

1.37

,38

.1.0

1 .1.2 1.1. <

1 .1*6

1 .1.7

1 .1.9 1.5 1 1.52

13 dB 12.32

12.31. 12.35

12.37

12.39

12.1.1

12.1.3

12.1.1* 12 .1.6 12 .1.8 12.50

12.52

12.52

14 dB 13.39

13.1.1 13.1.3 13. 1.5 13.1.7

13.1.8 13.50

13.52

13.51. 13.56

13.57

13.59

13.60

15 dB

11.. 31

11.. 35

11.. 39

II.. 1.3 11.. 1.6 11.. 50

11*. 5*. 11.. 56

11.. 61

11.. 65

11.. 69

11.. 73

11.. 71.

16 dB 15.35

15 .37 15.38

15 .1.0 15 .1.2 15 .1.1. 15.1.6 15 .1.7 15.1.9 15.51

15 .53 15 .55 15.55

17 dB 16.35

16.37

16.39

16.1.1 16.1.2

16.1.1. 16.1.6

16.1.8 16.50

16.52

16.53

16.55

16.56

18 dB :9 dB

17.51. 17.56

17.58

17.59

17.61

17.63

17.65

17.67

17.68

17.70

17.72

17. 7«. 17. ?5

18.32

18.38

18.1.1* 18.1*9 18.53

18.57

18.60 18.62

18.61. 18.65 18.65

18.65 18.65

20 dB 19. 51* 19.51*

19.51* 19.51*

19.51*

19.51*

19.51*

19.51* 19.51*

19.51.

19.51* 19.51*

19.51*

34
Table 2 (Continued)

CSLCULATION OF OUTPUT ATTENUATOR STEPS

GHz 1.0 2.0

3.0

5.0

6.0 7.0

8.0

9.0 10.0

11.0

12. G 12.

4

20 dB 19. S"* 19.5<» 19.51. 19. Si* 19.51*

19.51* 19.51*

19.51*

19.51* 19.51*

19.51* 19. 51* 19.51*

21 dB 20.35

20.35

20.35

20.35

20.35

20.35

20.35

20.35

20.35

20. 35 20.35

20.35

20.35

.22 dB 23 dB

21. 38 21.36

21. 38

21. 38

21. 38

21. 38

21. 3b 21.38

21. 38 21.38

21.38

21.38

21. 38

22.39

22.39

22.39

22.39

22.39

22. 39 22.39

22.39

22.39

22.39

22.39

22.39

22.39

24 dB

23.1*7

23.1*7

23.1*7

23.1.7 23.1*7

23.1*7

23.1.7

23.1*7 23.1*7

23.1*7

23.1*7 23. '7

23.1*7

25 dB

21*.

21*. 38

(.0 21*. 1*2 21*. 1*1. 21* .1*6

21*. 1*8 21*. 50

21*. 52

21.,

21.,

21*, 21..

51* 56

58

60

21*. 61

26 dB

25.1*2

25.1*2 25.1*2

25.1.2

25.1*2

25.1*2 25,1*2

25.1.2

25.1*2

25.1*2

25.1*2 25.1*2

25.1*2

27 dB

26.1*2

26.1*2 26. 1*2 26.1*2

26.1*2 26. 1*2 26.1*2 26.1*2

26.1*2 26.1*2 26. '2

26. 1*2 26.1*2

28 dB 27.61

27.61

27.61

27.61

27.61

27.61

27.61

27.61

27.61

27.61

27.61

27.61

27.61

29 dB 23.39

2a.>*<. 23.1*7 28.50

28.53

23.55

28.56

28.57

28.56

28.56

28.51* 28.52

28.51

30 dB

29.2«J 29.29

29.29

29.29

29.29

29.29

29.29

29.29

29,29

29,29

29.29

29.29

CALCULATION OF OUTPUT ATTENUATOR STEPS

GHz

1.2.

3,

1*, 5.6,

7.8.

9, 10. 11.0 12.0

12.1*

30 dB 29.29

29.29

2 9.39

29.29

29.29

29.29

29.29

29.29

29.29

29.29

29.29

29.29

29.29

31 dB 30.10

30.10

30.10

30.10

30.10

30.10

30.10

30.10

30.10

30.10

30.10

30.10

30.10

32 dB

31. II. 31. 11. 31. 11. 31. 11* 31. 11. 31. 11. 31.11*

31. 11* 31. 11. 31. 11. 31. 11. 31. 11. 31. II.

33 dB 32.11.

32.11. 32.11.

32.11. 32.11. 32.11*

32.11* 32.11*

32.11* 32. 11* 32.11*

32.11* 32. 11*

34 dB 33.22

33.22

33.22

33.22

33.22

33.22

33.22

33.22

33.22

33.22

33.22

33.22

33.22

35 dB

31*, 31*,

31*, 31*,

31*,

11* 16

16

20

21

31*. 23

31*. 25

31*. 27

31*. 29

31*. 31

31*. 33

31*. 35

31*. 36

36 dB 35.17

35.17

35.17

35.17

35.17

35.17

35.17

35.17

35.17

35.17

35.17

35.17

35.17

37 dB 36.18

36. 18 36.18

36. 1 8 36. 18

36. 18 36.18

36.18

36.18

36. 13

36. 18

36. 18 36.18

3B dB 37. 36 37.36

37.36

37. 36 37.36

37.36

37.36

37. 36 37.36

37. 36

37. 36 37. 36 37. 36

39 dB

33.11* 38.19

38.23

38.26

38.28

38. 30 38.31

38.32

33.32

38. 31

33. 30 38.28

38.27

40 dB 39.3V

39.3«» 39. SI* 39.31* 39.31*

39.3i» 39. 3f* 39.31* 39.31*

39.31*

39.3«»

39.31*

39.3«»

35
1. Table 2 ((Eontinued)

C4LCULATI0N OF OUTPUT ATTENUATOR STEPS

GHz 40 dB 41 dB 42 dB 43 dB 44 dB 45 dB 46 dB 47 dB 48 dB 49 dB 50 dB 1.0 39. Ji* '0.16 19 '.2.19 '3.27 '.'.19 1.5.22 <.6.23 1.7. 1.2 '8.20 i*<i,ZZ ^2.0 39. '0.16 '1.19 '2.19 '3.27 ''.21 '5.22 '6.23 '7.<^2 tti.Zk '9.2«» 3.0 39. 3'^ '0.16 '1.19 '2.19 '3.27 ''.23 1.5.22 '6.23 i*7.i*Z '8.28 it<i.ZS 39.3'. 1.0.16 1.1.19 '.2.19 '3.27 '.'..25 '5.22 '6.23 '7. '2 '8.31 '9.27

5.0 39.3'. '.0.16 'I. 19 '2.19 '.3.27 '.'..27 ',5.22 '.6.23 '.7. '2 '8.33 k<).Zi

6iD 39.3'. '.0.16 '.1.19 '.2.19 '.3.27 '.'..29 '.5.22 1.6.23 1*7.1*2 1.8.35 '9.30

7'.0 39. 3<^ '.0.16 '1.19 '.2.19 '.3.27 '.'..31 '.5.22 1.6.23 '.7. '2 '.8.36 'g.Sl

6.0 39. 3<^ '0.16 '1.19 '2.19 '3.27 ''.33 '5.22 '6.23 <»7.'»2 'S.S? 1.9.33 9.0 39. '.0.16 '1.19 (.2.19 '.3.27 '.'..35 '.5.22 '.6.23 '.7. '.2 '8.37 '.9.35 10.0 39. 3'^ '0.16 '1.19 1^2.19 '3.27 '.'..36 '.5.22 '.6.23 '7. '2 '.8.36 '9.36

11.0 39. Si^ '.0.16 '.1.19 '.2.19 '.3.27 i.<..38 '.5.22 1.6. 23 47. '.2 1.8.35 (.9.38 12.0 39.3'. '0.16 '.1.19 '2.19 1.3.27 ''..'0 '.5.22 1.6.23 1.7. '2 '.8.33 1.9.39

12.'. 39. 31^ '0.16 'I. 19 '2.19 1^3.27 ''.'1 '5.22 '6.23 '.7. '2 '8.32 <»9.(*0

CALCULATION OF OUTPUT ATTENUATOR STEPS

GHz 50 dB 51 dB 52 dB 53 dB 54 dB 55 dB 56 dB 57 dB 58 dB 59 dB 60 dB 1.0 '9.22 50. 01^ 51. 07 52. 07 53.15 5i^.07 55.10 56. 11 57.29 58.07 59.53

2.0 1.9.21. 50.05 51. 08 53.09 53.16 5i^.lO 55.12 56.12 57. 31 58. 13 59.53

3.0 i.^.:5 50.07 51. 10 52. 10 53. 18 51.. 1*. 55.13 56. li. 57.32 58. 19 59.53

1..0 1.9.27 50. 08 51. 11 52. 12 53.19 51.. 17 55.15 56.15 57. 31. 58.23 59.53

5.0 1.9.28 50. 10 51. 13 52. 13 53.21 5'.. 21 55.16 56. 17 57.35 58.27 59.53

6.0 1.9.30 50.11 51. 11. 52.15 53.22 5'.. 2'. 55.18 56. 18 57. 37 58. 31 59.53

7.0 "9.31 50. 13 51. 16 52.16 53.2'. 5'.. 28 55.19 56. 20 57.39 58.33 59.53

8.0 1.9.33 50.1'. 51.17 52.18 53.26 51..31 55.21 56.21 57. 1.0 .58.36 59.53

9.0 1.9.35 50.16 51. 19 52.20 53.27 51.. 35 55.23 56.23 57.1.2 58.37 59.53

10.0 1.9.36 50.17 51.20 52.21 53.29 51.. 38 55.24 56.21. 57.1.3 58.36 59.53

11.0 i.y.38 50.19 51.22 52.23 53.30 5'.. '.2 55.26 56.26 57. '.5 58.38 59.53

12.0 1.9.39 50.20 51. 23 52.21. 53.32 54. (.5 55.27 56.28 57.'.6 58.38 59.53

12.'. 49.40 50.21 51. 24 52.25 53.32 54.47 55.28 56.28 57.47 58.37 59.53

36
Table 2 (Continued)

CALCULATION OF OUTPUT ATTENUATOR STEPS

GHz 1.0 2.0

3.0

<».0 5.0

6.0

7.0 8.0

9.0 10.0

11.0 12.0

12.

60 dB 59.53

59.53

59.53

59.53

59.53

59.53

59.53

59.53

59.53

59.53

59.53

59.53

59.53

61 dB 60.35

60.35

60.35

60.35

60.35

60.35

60. 35 60.35

60. 35

60. 35 60.35

60. 35 60.35

62 dB 61. 3C 61.38

61. 3d

61. 38

61. 36

61. 38

61. 38 61.38

61. 38

61. 38

61. 38 61.38

61.38

63 dB 62.38

62.38

62.38

62. 38 62.38

62.38

62.38

62.38

62. 38

62. 38 62,38

62.38

62.38

64 dB

63.i»6

63.<»6 63. '*6 63.'«6 63. '«6

63. '•6 63.1*6 63. '6

63. '6

63.t»6

63.'*6 63. '»6

65 dB 64.38

64,<»0

6<».50 6'*.52

6'».5I«

6'*. 55

6'».57

&'».59

6'«.60

66 dB

65,1*1 65.*»1 65.1*1

65.'*1

65.1*1

65.1*1 65.1*1

65.1*1

65.1*1

65.1*1 65.1*1

65.1*1 65.1*1

67 dB

66.1*2

66.1*2

66.1*2 66.1*2

66.1*2

66.1*2

66.1*2 66. 1*2 66. 1*2 66.1*2

66.1*2

66.1*2 66.1*2

68 dB 67.61

67.61

67.61

67.61

67.61

67.61

67.61

67.61

67.61

67.61

67.61

67.61

67.61

69 dB 68.38

68.(*3

68,1*7

68. 5 0 68.52

68, 5h

63.55

68.56

68.58

68.55

63.51* 68.52

68.51

70 dB 68.99

69.00

69.01

69.02

69.03

bS.Ql*

69.05

69.06

69.07

69.98

69.09

69,11

69.11

CALCULATION OF OUTPUT ATTENUATOR STEPS

GHz 1.0 2.0

3.0

i«.0 5.0

6.0

7.0 8.0 9.0

10.0 11.0

12.0

12.1*

70 dB 68.99

69.00

69.01

69.02

69,0 3 69.01* 69.05

69.06

69.07

69.08

69.09

69.11

69.11

71 dB 69.80

69. 81 69.32

69.83

69.35

69. 86 69.87

69.88

69.89

69.90

69.91

69.92

69.92

72 dB 70.33

70.81* 70.85

70.86

70. 88 70.89

70.90

70.91

70.92

70.93

70.91* 70.95

70.95

73 dB 71.81* 71.85

71.86

71.87

71.88

71.89

71.90

71.91

71.92

71.93

71.91* 71.96

71.96

74 dB 72.92

72,93

72.91. 72.95

72.96

72.97

72.98

72.99

73.00

73.01

73.02

73.03

73.03

75 dB 73.83

73.86

73.89

73.92

73.95

73.98

71*. 02

71*. 01* 71*. 07

71*. 13

71*. 13

71*. 17

71*. 18

76 dB

71.. 87

71.. 38

71.. 89

71.. 90

71.. 91

7i..92

71.. 93

71.. 91* 71*. 95

71.. 96

71.. 97

71.. 99

71*. 99

77 dB 75.87

75.88

75.90

75.91

75.92

75.9 3 75.91* 75.95

75.96

75.97

75.98

75.99

75.99

78 d3 77. 06 77. 07 77.08

77. 09 77.10

77.11

77.12

77.13

77.11* 77. 16 77.17

77.18

77.18

79 dB

77.81. 77.90

77.91* 77.99

78.02

78.05

78. 07 78.09

78.10

78.10

78. 10 78.09

78.08

60 dB 78.92

78. 3S 73.85

78.31 78.77

78.7«» 73.70 78.66

78.63

78.59

78.55

76.52

78.50

37
Table 2 (Continued)

CftLCULATION OF OUTPUT ATTENUATOR STEPS

GHz 80 dB 81 dB 82 dB 83 dB 84 dB 85 dB 86 dB 87 dB 88 dB 89 dB 90 dB 1.0

2.

3.0

<«.o 5.0 b.O

7.0 e.Q

9.0

10.0

11.0

13.0

12. <»

78.92

78.88

78.85

78.81

78.77

78.71* 78.70

78.6b

78.63

78.59

78.55

78.52

78.50

79.73

79.70

79.66

79.62

79.59

79.55

79.51

79. '•a 79.'»'» 79. '0 79.36

79.33

79.31

80. 76 80.73

80.69

80.65

80.62

80. 58

80.5't 80.51

80. '7

80. it3 80.39

80.36

80. 3U

81.77

81.73

61.70

81.66

81. 62 81.59

81.55

81.51

81.<»8 81. i**. 81. 'O 81.37

81.35

62. a"* 82.81

82.77

82.73

82.70 82.66

82.62

82.59

82.55

82.51

82.'t8

82.'*t» 82.<*3

83.76

83.75

83.73

83.71

83.69

83.68

83.66

83.6*. 83. 63 83.61

83.59

83.58

83.57

61*. 3 0 e'*.76 84.73

81.. 69

8i..65

8i..62

at*. 56

8l».51

8i».'»7 B'*.i*Z

81*, 1*0 8<*.38

85.30 86.99

85.77

85.73

85.69

85.66

85.6 2 85.58

65.55

85.51

85. 1.7 85.'fi* 85.t.0 85. 36

86.95

86.92

86. 38 86. ftit 86.81

86. 77 86. 73 86.70

86. 66 86.62

86.59

86.57

87.77

87. 78

87.78

87.77

87.76

87.7'. 87.72

87.69

87.65

87.61

87.56

87.50

67.1.7

8S.73

88.67

88.62

88.57

88.51

88.1.6

88.1.0 88. 3S 88.30

88. 2i. 88.19

88.1(» 88.11

CALCULATION OF OUTPUT ATTENUATOR STEPS

GHz 1.0 2.0

3.0

1..0 5.0 6.0

7.8.

9. 10, 11

12.

12.

90 dB 88.73

88.67

88.62

88.57

88.51

88.1.6 88. 1.0 88.35

88.3 0 88.21. 88.19

88.11. 88.11

91 dB

89.51.

89.1.9 89.1.3 89.38

89.32

89.27

89.22

89.16

89.11

89. 06 89. 00 88.95

88.93

92 dB 90.57

90.52

90. 1.6 90.1.1 90. 35

90. 30 90.25

90.19

90.11.

90. 09 90.0 3 89. 98 89.96

93 dB 91.58

91.52

91. 1.7 91.1.2 91.36

91.31

91.25

91.20

91. 15

91. 09

91 .01. 90.99

90.96

94 dB 92.65

92.60

92.51. 92.1.9

92.1.1. 92.38

92.33

92.28

92.22

92.17

92.11

92.06

92.01.

95 dB 93.57

93. 51. 93.50

93.«.7

93.1.3

93.1.0 93.37

93.33

93. 30 93.26

93.23

93.20

93. 18

96 dB 9t..61

91.. 55

91.. 5 0 91.. 1.5 91.. 39

91*. 31. 91.. 2 8

91.. 23

91.. 18

91.. 12

91.. 07

91.. 02 93.99

97 dB 95.61

95.56

95.50

95.1.5

95.1.0

95.31. 95.29

95.23

95.18

95. 13 95.07

95.02

95.00

98 dB 96.80

96. 71. 96.69

96.61. 96.58

96.53

96.1.7

96.1.2 96.37

96. 31 96.26

96.21

96.18

99 dB 97.58

97.57

97.55

97. 53

97.50

97.1.7

97.1.2 97.38

97.32

97.26

97.19

97.12

97.09

38
APPENDIX B

~ Table 3

'DBM (NEGATIVE) TO MZCR3V0LTS

(Referenced to 50 ohms)

DBM MILL I WA TTS DB/MICROVOLT MICPOVOLTS

0 . 1.0000000 106. 98970 2.2360f>8C*-05

-r.'o d o a c 0 o" .79'*328 23 105.98970 * 1.9926977fr05

-2.0000000 . 630 957 3'* iOt*. Q8970 1. 776 t719*-05

-3 ,0000000 . 50118723 103. 98970 1.58301«*9+05

-'t. 0000000 . 398 1 07 17 10 2. 96 970 * I.'^IO 8635*05

~-5 . 00 300 0 0 .31622777 101. 989/0 * 1 « 2 5 7 * 3 3 <* 0 5

-6.0000000 . 251 138 6'* 10 0. 98970 1.1206 88 7*- 05

-7 .00 0 00 0 0

-- .19952623 9 9 <. 98 97 0 0 9 » 9 9 8 1 * 3 8 0 ^ -8.0000000 « 15 a '8 9 32 98. 989700 8.9019'*70*0'»

-9. CO Olio CO . 1258925'» 97. 58970 C 7.9338686+0'*

-lO.OCOOOQ .10000000 96.989700 7.0710678t0'»

-11.00 00 0 0 . 079'+32823 95. 989700 b.3020958 + 0i» 12 . 0 0 0 0 OC . 063 0 95 73't gi,, 959700 5 . 5 1 6 7 '» 8 Q •»• 0 *ft -13,000000 . 050118723 93.589700 * 5.0 Q59326-»-0it

-1^. 00 0000 . 039810 717 92. St970 0 * '.'615'*22*-0'»

•15 .000000 .031622 777 91.9897 0 0 3. 9763536+-0'*

-16.00000 3 . 025113 86'* 90. ^89700 3 . 5 < 3 9 2 8 9 0 1* -17.000000 . 019952623 89. 98^700 3. 158530 0 + 0'* -18 . 00 000:] .015 8 '+8 932 8 8.989700 2.8150'*2 8 + C'»~ -IQ, 000000 . 01258925'* 87. C8970 0 2.50890 95fQ'*

-20.000000 . 010000000 86.989700 2.2360030+0%

•21 . 00 0000 . 0079''32823

' 85. 9897 0 0 1.9928977+0't

'22. 00 0000 . 006309573'* 8'*. 98970 0 * 1.7761719fO'»

"23.00000U . 0050118723 83. 98970 0 1 . 5 3 3 0 1 ' 9 * 0 '* 2it. 00 000 0 .0039310717 6 2. 98 970 0 i. '108635 <0'* •25 .00 0000 . 0031622777 8 1 « 96 970 0 1.257'^33'^ + 0'* 2u . 00 0 OOfJ . 002511886V 8 0.989700 1.12 0 68 8 7+0'*

•27.300000 . 0019952623 79. 98970 0 9 . 9 8 8 1 ** 8 8 + 0 3

•28 . OOCOOO . 0 01564 3932 78. 589700 8. 9019 0 + 03

•29 . 000000 . 001258925'* 77« 98970 0 7.933 d68o + C3

•30 . OOOCOO . .0 0100 0 0000 78. 989700 7. 0710678+03

•31 . 00 0000 * 7.9'*32823-0«* 75. 58970 0 6.3020953+03

32.00000 0 * 6. 309573'*- Qi* 7 U. <=8970Q * 5 . 6 1 6 7 ' 5 8 + 0 3

•33 . 00 0000 * 5. 01 18/ 23-0 £ 73» 96970C 5. 0 059326 + 03

3'*. 000000 3.9810 717-0'* ' 72. O8970 0 ' • ** 6 1 5 i* 2 2 + 0 3

35. 00 3000 3. 1622777-0'* 71,0307(50 3.9763536+03

36 . 00 0000 2. 511886't-O'* 70. 989700 * 3. 5'+3 9239+03

37.000000 1 e 9°5262 3-01* 69. ^=8970 0 3. 1585300 + 03

* 39.000 0 00 1 . 25a925'*-a'* 67. 89700 2.508909^+03

* 1.0000000-01* 66.98 9700 2.2 360680+03

<t 1 .000000 * 7.9<*32823-05 65. 589700 1.9928977+03

'2. 0 00000 6.309573'*-05 6'*. 9S9700 1.7761719+03

tfS.COOOOO * 5. 0118723-05 63. 5S9700 1.58301<*9 + 03

. 00 cooo * 3.9810717-05 62. 589700 * l.'*108635 + 03

'5. 00 0000 3. 1622/77-05 61.589700 1.257'*33'*i-03

i»6. 000000 * 2.511886'*-05 6 0, 58970 0 1.1206867+03

'7. 000000 * 1.9952623-05 59. 559700 g.9381'*68 + 02

'6. 000000 1 .5848932- 05 5 8. 5C970 0 * 8.9019'^70 + 02

'9. 000000 1.258925't-05 57.589700 7. 9338685+02

39
Table .3. (Continued). .

DOM MILLIWATTS

OBM (NEGATIVE) TO MICROVOLTS

(Referenced to 50 ohms)

DB/MICROVQLT MICROVOLTS

-5u.oonooo 100 [) 000 0- 05 56. 989^00 7 . 0 7 1 0 6 7 8 *• 0 2

-51.000000 7. 06 55.96970 0 * 6. 3 02 0 958 •02

-52. 00 PQOO 6. 309573if- C& 5t+. 9'69700 5.6167'*86>02

-53. 00 OOCO * 5. 01iC723- 06 53. 989700 5. 0059326+02

-5-^.oooono 3. 9aiC717- OS 52.969700 if. '615^22*02

-55 .OOOOOC * 3. 1622777- 06 51. 98 97 0 0 3.976353bf 02

-56.00 0 000 2. 511886f+- 06 5 0. «:-3 970 0 3.54*39289 + 02

-57.000000 1. 9952623- 06 ^49. 989700 3.1535300+02

-56 . OC 0 jOO 1. 56'46932- 06 969700 2.8150^+26+02

-59.00 0000 1. 256925'-- 06 ^+7. 969700 2.5089095+02

60.0 0GOCO

61.000000

62.000000

65.000000

6 if. 00 0 COO

'j5 . OOOCOC

000000

000000

00 00 00"

oocooo

-66

•67

•66

'69

i. 0 00 000 0-0 6

7.9^+32823-07

*^ 6.'309573i+-07

5.0118723-07

3.9810717-07

3.1622777-07

> 2.51i68bit-07

1.9952623-07

1.5643932-07

1.258925^-07

tt6. 989700

5. 93970 0 tfV. <;e97 0 0 43.989700

42.989700

41. 989700

40. 959700

39.989700

3 8. 98 970 0 37. 989700

• 2.2360680+32

1.9923977+02

* 1 .776i719^02'

1.5830149+02

* 1.4103635+02

* 1.2574334+02

1.1206887+02

99.831488

89. 019470

" 79.333686

-70.000000 1.000000 0-•07 36. 989700 70 . 710 678

-71.00 0 0 00 7. 9'i32823- 0 6 35. 989700 63.020958

-72. OOCOOO * 6. 3095734- 08 34. 989700 56.167488

-73.000000 5; 0118723- 08 33. 989700

" 50.059326

-74.00 0 000 3.9610717- 08 32. 989700 44.615422

' -75.000000 3. 1622777- 0 8 31. 989700 39.763536

-76.00 0 000 2.5118364- 08 30. 989700 35.439289

-77.000000 1. 9952623- 03 29. 989700 31.535300

-73.000000 1.5843932- 06 28. 989700 28.150 42 8 "-79.00 0 0 00 1. 2539254- 08 27.969700 25. 089095"

-30.000000 -' 1 . 0 0 0 0 0 0 0

•• 03 2 6. 989700 22.360680

-31.000000 * 7.9432323- 09 25. 989700 19. 923977

-52.000000 * 6. 3 0 95 73 4- 09 24, 989700 17.761719

-33,030000 * 5 . 0116723- 09 2 3. 9897 0 0 15.830 149

-84.000000 3.9810717- 09 22. 9597 0 0 14. 103635

-85.000000 * 3. 1622777- 09 21. 96 97 0 0 12.574334

-56. 000000 2.5116864- 09 20. 989700 11.206887

-S7 .000000 1.9952623- 09 19. 969700 9.9381488

-68.000000 1. 5848932- 09 "18. 989700 8.9019470

-39. OOOUOO 1. 253925'*- 09 17. 989700 7.9338686

-90.000000 l.OOOCOOO- 09 16. 9'^9700 7.0710678

-91.000000 7. 9432323- 10 15. 9? 97 0 0

" 6.3020956

-92.000000 6.3095734- 10 14. 98 9 7 0 0 5.6167488

" -}3. 000000 5.0115723- 10 13. 939700 ' 5. 0059326

-94 .000000 3.9810717- 10 12. 98 97 0 0 4. 4615422

- 05 . 00 0003 3.1622777- 10 " li . 9S9 70 0 ~" 3.9763536

-96. 00 OQOO * 2. 5118864- 10 10. 989700 3.5439289

-97.000000 * 1.9952623- 10 9. 9597000 3. 1535300

-98.00 000 0 1 .5848932- 10 e. 9697000 2. 8150428

-99.00 0 00 0 1.2589254- 10 7. 9897000 2.5 C3 90 95

40
APPENDIX C. MAINTENANCE

C.l. Power Supply Section

All power supplies except that for the 1-watt, 1 to 2 GHz amplifier are commercial models. Their voltages should be set to the values shown in

figure 15 using the screwdriver adjustments on the individual units.

The amplifier supply derives +24 volts and +15 volts from the +28 volt

commercial unit by using zener diodes. The nominal +24 volts is produced

from two 12-volt zener diodes in series. The +15 volts is produced by a 12-volt zener diode which drops the +28 volts to approximately 16 volts and

the adjustable 50-ohm tapped resistor.

A schematic diagram of a safety interlock is shown in figure 16. This

circuit protects the VTO and the 1-watt amplifier should certain critical

voltages fail. The manufacturer states the VTO should not be powered if

the tuning voltage is removed, nor should the -5 volts be applied to the

1-watt amplifier if the +24 and +15 volts are not present.

C.2. VTO Alignment

Figure 10 should be referred to when performing this operation. An

electronic counter capable of measuring 1 to 2 GHz should be connected to the

output of the remote head, and the Standard Signal System switched to 1-2 GHz

range. The PULSE-CW switch (fig. 17) should be in CW.

CAUTION: Up to 1 watt can be delivered in this range so make sure enough attenuation is inserted to protect the counter.

1. Turn the FREQUENCY ADJUST knob full CCW. This applies 0 volts to

the tuning terminal on the VTO. The counter should read approximately 997 MHz and the frequency meter on the Standard Signal

System should indicate 1000 MHz.

2. Set 500-ohm, 2 GHz ADJUST resistor for maximum resistance. Turn

FREQUENCY ADJUST knob full CW. Set 2 GHz ADJUST resistor so counter reads approximately 2002 MHz. Allow several minutes for

frequency to stabilize.

3. Set 2 GHz SPAN ADJ. so meter reads 2 GHz.

4. Switch to 8-12.4 GHz range and set FREQUENCY ADJUST knob full CCW.

5. Set 8-12.4 GHz LOWER LIMIT ADJUST so counter reads 1141.4 MHz.

6. Rotate FREQUENCY ADJUST knob full CW and set 8-12.4 GHz UPPER

LIMIT ADJUST so counter reads 1785.7 MHz.

7. Set 8-12.4 GHz SPAN ADJUST so meter reads 12.5 GHz.

41
C.3. YIG Lock Circuit Alignment

The equipment required for this operation is as follows:

a. A clip-on milliammeter connected to the negative tuning lead

(black) of the YIG.

b. An oscilloscope connected to the output of the ramp generator

(see fig. 4)

• • c. A spectrum analyzer (range 2-12.4 GHz) connected to the output

of the remote head. This is used to measure the frequency and

output power. A frequency counter may be substituted. If so,

during the following steps sufficient power can be realized by

obtaining as large as possible readings on the monitor. After

alignment power output should be measured to verify the output

level is greater than the reference level.

Alignment of 2-4 GHz range

1. Switch Standard Signal System to 2-4 GHz band.

2. Set YIG bias (fig. 12) to 0.75 volt.

3. Turn FREQUENCY ADJUST knob full CCW and adjust LOW LIMIT SET

pot on YIG lock card so milliamme,ter reads 70 mA.

4. Turn FREQUENCY ADJUST knob full CW and adjust HIGH LIMIT SET

pot so milliammeter reads 145 mA.

5. Increase LEVEL SET pot to obtain lock as indicated by LED,

display labeled YIG LOCK. Increase level to obtain higher

output over entire 2-4 GHz range.

6. Slightly decrease LOW LIMIT pot to increase output power.

7. Break lock by turning off switch on frequency tuning chassis.

Then re-start VTO with RESET button.

8. The ramping generator should start, effect a lock and shut off.

Adjust COMPARATOR REFERENCE pqt to obtain proper operation

as observed on the oscilloscope.

9. Repeat steps 6 through 8 until sufficient power is obtained.

Alignment of 4-8 GHz range

1. Switch Standard Signal System to 4-8 GHz band.

2. Repeat steps of 2-4 GHz alignment except set YIG bias to

-1.0 volts, set LOW LIMIT current to 145 mA and HIGH LIMIT

current to 295 mA.

Alignment of 8-12.4 GHz range

1. Switch Standard Signal System to 8-12.4 GHz band and

decrease monitor range by 10 dB.

42
2. Repeat steps of 2-4 GHz alignment except set YIG bias to

-1.4 volts, set LOW LIMIT current to 295 mA and HIGH LIMIT

current to 460 mA.

3. Output power on this range should be 0.1 mW or greater.

Adjustment of diode switch bias

1. Switch PULSE-CW switch to CW.

2. Set CW ON pot (see fig. 17) so -10 volts is applied to

wiper of SlG.

3. Switch PULSE-CW switch to PULSE. Set Standard Signal System

to 1 to 2 GHz band,

4. Adjust 1-2 GHz BIAS pot for 100 mA current. This can be

measured with a clip-on milliammeter connected on the lead

to the pot.

5. Repeat steps 3 and 4 for the other three bands.

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NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PLIHLICATION OR REPORT NO. NBSIR 74-371

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITL1-; AND SUHl FI LL

Broadband Pulsec

for Field Inten

i/CW Calibration Signal Standard

sity Meter Receivers

5. Publication Date

6. Performing Organization Code

7. AU rilOR(S)

Simpson, Philip A.

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Proiect/Task/Work Unit No. 2765171

11. C'ontract /Grant No. CCG 72-70

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

Dept. of Defense/Calibration Coordination Group

c/o Mr. M.L. Fruechtenicht AMSMI-M, Bldg. 5435

U.S. Army Metrology & Calibration Center

Redstone Arsenal, Alabama 35809

13. Type of Report & Period Covered

Final Report

14. Sponsoring Agency Code

CCG

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or /ess factual summary of most si^ificant information. If document includes a significant

bibliography or literature survey, mention it here.) This report describes the constructional details and the operation

of a system for calibrating microwave field intensity meter (FIM)

receivers in the frequency range 1 to 12.4 GHz. The system uses

known levels of CW power to calibrate the receiver, and short

duration (~20 ns) rf bursts to measure the bandwidth. An error

analysis of the system is given. Schematic drawings of various

circuits in the system are provided along with charts and tables for

facilitating computations encountered when performing calibrations.

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 semicolons

Broadband signal generator; impulse bandwidth; receiver bandwidth

calibration; rf burst generator; spectral intensity.

18. AVAILABILITY Ix'' Unlimited

I

' For Official Distribution. Do Not Release to NTIS

I

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

~1 Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCL ASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

22. Price

USCOMM-ERI, USCOMM-DC 29042-P74