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'JET PROPULSION LABORATORY

California Institute of Technology

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This work wa. performed for the Jet Propulsion Labor-atomy,

California Institute of Technology, sponsore_ by the

National Aeronautics and Space Adm_i_'_o_ under

Contract NA_7.100.

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https://ntrs.nasa.gov/search.jsp?R=19680009921 2020-03-24T22:42:03+00:00Z

SRS TECHNICAL REPORT

TR-DAI522 A

JPL CONTRACT 951290

DESIGN STUDY OF THE JPL S-BAND

TURNAROUND RANGING TRANSPONDER

FINAL ENGINEERING REPORT

1 November 1967

Submitted to:

JET PROPULSION LABORATORY

California Institute of Technology

Pasadena, California

This work was performed for the Jet Propulsion _,California Institute of Technology, sponsored by the

National Aeronautics and Space Adminlst_tlom tmde_Contract NAS7-100.

Prepared by:

PHILCO CORPORATION

A Subsidiary of Ford Motor Company

SRS Division

Palo Alto, California

PHILCO.I=O _ _ CORPORATION

SDace _ _B-entry

Systems Division

Section

1

2

4

pKEGEDING "PAGB BLA_, I_IOT: FIU_ED.TR-DAI522A

TABLE OF CONTENTS

INTRODUCTION

SLH_IARY

2.1 Original JPL Transponder Design Deficiencies

2.2 Phase I

2.3 Phase II

2.3.1 Ranging System Evaluation

2.3.2 S-Band Phase Evaluation

2.3.3 Analysis and Study

2.3.4 Recommended Changes

EVALUATION TESTS (Phase II)

3.1 Transponder Overall S-Band /"VCO"/ Ranging

Phase vs Temperature

3.1.1 Entire Transponder

3.1.2 Six Packs (3)

3.1.3 Individual Modules (13)

3.2 Diagnostic Tests

3.2.1 _dule

3.2.2 Special

ANALYSIS AND STUDY (Phase II)

4.1 Ranging Delay and Ranging Delay Variation

4.1.1 Ranging Delay due to Interstage

Coupling Networks

4.1.2 Delay Variation Produced in the

Demodulation Process

I-i

2-1

2-1

2-3

2-5

2-5

2-6

2-6

2-7

3-1

3-1

3-9

3-15

3-32

3-55

3-55

3-78

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4-1

4-4

4-13

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TR-DAI522A

TABLE OF CONTENTS (Cont 'd)

Section

4.2

4.2.1

4.2.2

Transponder Phase Relationships

General Relationships

Ranging Delay Produced by VCO

Crystal Temperature Characteristic

4.2.3 "Cog" Phase Jumps

4.3 Frequency Ratio Study

VIDEO AMPLIFIER

5.1 Functional Description

5.2 Specification Requirements

5.3 Problems in Mariner C Design

5.4 SRS Module Design

5.5 Test Data

5.6 Comparison with Mariner C Module

CONCLUSIONS AND RECOMMENDATIONS

6.1 Discussion and Review

6.2 Recommendations for Future Work

4-18

4-18

4-21

4-24

4= 27

5-I

5-1

5-1

5-3

5-6

5-6

APPENDIX (PHASE IX)

I

IV

V

VI

VII

IpH,-=oj pHIL.I=O.FOR O CORPORATION

Phase Shift and Group Delay vs Detuning for Single

and Transitional Coupled Double Tuned Filters

Demodulations of a Trapezoidal Phase Modulated Carrier

Delay Produced in the Demodulation Process

3.1 Distorted Ranging Signal

3.2 Detector Reference Signal

Spectrum Analysls of a Trapezoidal Modulated Carrier

Transponder Phase Analysis

Frequency Ratio Study

Ranglng Test Information

iv

A.I-I

A.2-1

A.3-1

A.3-5

A.4-1

A.5-1

A.6-1

A.7-!

Space I_ ReentrySystems Division

SECTION 1

TR-DAI522A

DESIGN STUDY

OF THE

S-BAND TURNAROUND RANGING TRANSPONDER

FINAL ENGINEERING REPORT

1.0 INTRODUCTION

JPL Contract 951290 provides for a design study program of the JPL S-Band

Turnaround Ranging Transponder directed toward improving the Transponder

performance. The program was divided into two parts: Phase I and Phase II.

The required overall effort is divided into three broad areas which include:

ae A review of all the transponder circuitry directed toward

improving the unit's performance, stability, efficiency,

and reliability.

b, A detail analysis of specific transponder problem areas which

have evolved through previous use of the unit in the Mariner

C Mars Mission.

Ce Transponder in-lock ranging and S'band carrier phase

stability as a function of temperature, using JPL-supplied

transponder.

The "Interim Engineering Report," WDL-TR3066, provides the results of the

/

I-I

DHILCO-FO_Q CC)RPO_ATDON

Space & Re-entrySystems Div|s|on

TR-DAI522A

Phase I effort which accomplished "a" and %" above. Included is a complete

presentation of the design investigation, analysis and testing accomplished

in the Phase I effort.

This 'Tinal Engineering Report" provides a summary of the Phase I effort plus

the results accomplished in "c" above.

1-2

l -col _HILCO-_Om 0 _Om POTATION

Space & Re-entry

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TR- DA15 22A

SECTION 2

SUMMARY

2.1 ORIGINAL JPL TRANSPONDER DESIGN DEFICIENCIES

The original JPL S-band transponder was developed during 1962 for an S-band

Mariner-Mars Mission in 1964. Some of the circuitry was left identical to

its L-band predecessor designed in 1959. Although the transponder has per-

formed exceedingly well, there have been a number of problems which have

occurred during calibration, test and mission operation. In addition, many

improvements have been made in component technology and reilabilitywhich

should be incorporated to update the design.

Of specific concern are the following items which have received specific

attention during the program:

l•o Self lock - the mechanism by which the Transponder

receiver is caused to phase lock onto a Transponder-

generated signal when the turnaround ranging module

is turned on was studied and analyzed.

e Turnaround ranging response - the turnaround response to

modulation was analyzed for purposes of both improving

the phase stability over the operating temperature range

and providing reproducibility from unit to unit.

. Modulation bandwidth - the •required modulation bandwidth

was difficult to achieve and required very careful and

time-consuming alignment of the exciter stages.

2-1

IpxL=oj pHILCO.FC)_ 0 CO_P_ATI_N

Space & R_ntrysystems Division

TR-DAI522A

. Phase modulator - the sensitivity and stability of the phase

modulator was studied and methods for improvement recommended.

. Automatic galn control (AGC) - the AGC circuits and the AGe-

controlled circuits were analyzed to improve performance and

stability over the operating temperature range.

. Receiver best-lock-frequency drift - the receiver best-lock-

frequency which drifts extensively with time and temperature

was studied and improved.

. Auxiliary oscillator frequency - the auxiliary oscillator

frequency was sensitive to the value of the transfer command

voltage.

. Power supply and monitor point lead filtering - the power

supply and monitor point lead filtering and decoupling was

analyzed for possible reduction in low-frequency feedback and

radio frequency (RF) leakage.

. Varactor multipliers - the design of the varactor multipliers

was analyzed to improve the reliability and minimize spurious

outputs from the exciter.

10. Part Selection - by adequate design and tolerance analysis,

a reduction in the number of parts which required selection

of parameters during the assembly and testing phase was made.

Ii. Receiver noise figure - the receiver circuitry was analyzed

to reduce the receiver noise figure within the constraints

of the conventional circutry now used.

12. Component type reduction- where possible by adequate design,

a reduction in the number of types of components required was

ma_e .-2-2

p_.I|LCO.FO R D CORPORATION

Space & ]::_e_ntrySystemm [_ivi_ion

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TR-DAI522A

In addition to the detailed analysis of these specific transponder areas a

review was performed of all the transponder's circuitry. This effort was

directed toward improving the units performance, stability, efficiency,

and reliability.

2.2 PHASE I

Phase I of this program was divided into two major areas of detail module

design and transponder system analysis.

Table 2-1 provides a summary of the module study, design, and test efforts

completed.

The transponder system analysis, design, and test was divided into five

major areas as follows:

a.

b.

C.

d.

e.

Transponder Self-Lock

Ranging Delay and Bandwidth

Automatic Gain Control System

DC Power Considerations

Reliability Improvement.

Specific details of the Phase I effort are included in WDL-TR3066, "Design

Study of the JPL S-Band Turnaround Ranging Transponder, Interim Engineering

Report" dated 19 September, 1966.

2-3

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TR-DAI522A

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TABLE 2-I

/

S-BAND TRANSPONDER DESIGN STUDY PHASE I MODULE EFFORT ACCOMPLISHED

Module Analyzed Tested RedesignedAnd Tes ted

Mixer Preamplifier

47 Mc IF Amplifier

9.56 _ IF Amplifier

Phase Detector

AGC Detector

Frequency Divider

VCO

X36 Multiplier

Auxiliary Oscillator

X30 Multiplier

Isolation Amplifier

Video Amplifier

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

CZ)

X

X

(2)

(2)

X

(i) Mixer Portion Only

(2) Oscillator Portion Only

PH|LCO.POR O C(_I ._O _ATt (_N

2-4

Space & ReentrySystems [Division

TR-DAI522

/I

2.3 PHASE II

A major part of the Phase II effort was spent in a test program with the

purpose of evaluating and isolating the causes of S-band carrier phase

shift and ranging delay variation in the Mariner C transponder, as a

function of temperature.

In addition to these tests, specific diagnostic tests were performed on

several of the modules.

The principal goal of the analysis and study effort was to relate the

ranging delay and S-band phase temperature data to transponder circuit

functions. In addition to this, a study was made to determine the optimum

transmlt-to-recelve frequency ratio, from the transponder viewpoint, for

the proposed change in the DSIF band occupancy.

Finally, an SRS version of the Video Amplifier was developed as part of

the Phase II effort.

2.3.1 RanEinz System Evaluation

Measurements show that the major cause of ranging delay variations in the

JPL Mariner "C" transponder under temperature varying conditions is due to

the following two conditions:

a.

b.

Distortion of the ranging signal.

Variation in the alignment of the ranging detector reference

phase relative to the carrier.

The combined effect of these two conditions is to produce an incremental

range delay that varies nonlinearly as a function of the misalignment.

2-5

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Space £, ReentrySystems Div|aicn

/,4%,

TR-DAI522

The major cause of distortion is due to reactive loading at the second

mixer, due to the input impedance of the crystal filter. The 9.56 MHz

I.F. Amplifier is the major cause of reference phase variations in the

ranging detector.

2.3.2 S-Band Phase Evaluation

Measurements show that the S-band Phase shifted fairly linearly with

temperature in the case of the entire transponder. The total variation

throughout the temperature range is 22.2 cycles.

Four modules were mainly responsible for the phase shift.

order:

ao

b.

C.

d.

VC0 and X3 Multiplier (13 cycles)

Aux-Osc., Mod., and X4 Multiplier (5.1 cycles)

X30 Multiplier (4.4 cycles)

X36 Multiplier (3.5 cycles)

These are, in

The large variation in S-band phase caused by the VCO was not expected.

One reason for the large variation is due to the fact that the phase

multiplication following the VC0 is 120 times.

The results of the S-band phase measurements are summarized in Table 2.3.1-

2.3.3 Analysis and Study

The analysis and study efforts combined with the various measurements made

in the program indicate that:

2-6

I, PHILCO 1_PH|_=CO*FO RO CORPQRAT_ON

Space _ Reentry6ystern_ Division

TR-DAI522

/3

a. Group delay in RF stages due to bandpass interstage coupling

networks, and phase shift of the fundamental component of thet:

498 KH z square wave in video stages, is responsible for almost

all of the measured ranging delay time in the transponder.

These are normal, unavoidable delay phenomenon and result mainly

from bandwidth limiting requirements.

bo Ranging delay variations measured in the JPL transponder are

produced principally in the demodulation process, and are caused

by variations in the reference phase relative to the carrier.

This phenomenon can be corrected to acceptable limits.

A module-to-module analysis was performed in order to obtain calculated

values for nominal ranging delay and ranging delay variation due to inter-

stage coupling networks so that expected and measured data at normal

operating temperatures and temperature varying conditions could be compared

directly when possible. The overall transponder expected ranging delay

and ranging delay variatlon due to interstage coupling networks is then

taken to be equal to the sum of the individual module values. The results

are presented in Table 2.3.1-2.

2.3.4 Recommended Chan_es

The recommended design changes are listed as follows:

a.

b.

Isolate the crystal filter from the second mixer by adding a

unity gain isolation amplifier in the 47.8 MH I.F. module.z

Tighten the phase specification of the 9.56 MH I.F. modulez

to_ I0 degrees over the operating temperature range.

2-7

JPHL=oI PHILCO-FORO =ORPO_ATION

Bpace & ReentrySystems Division

TR-DAI522

C.

de

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f.

g.

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i.

Specify the Frequency Divider module phase variation between

its three outputs: + 3 degrees over the operating temperature.

Specify that 4.78 MH z output of the Frequency Divider shall be

at least -60 db below the 9.56 MH output.Z

Control the overall misalignment between reference and carrier

in the ranging detector to_ 20 degrees over the operating

temperature.

Provide adequate isolation to impedance variations at the

input of Frequency Divider module and the output of the VCO

module.

Provide a transient-free bias source to the varicap in the VCO

module.

Eliminate the switching transient caused by turning on the

ranging channel.

Replace the JPL Video Amplifier module with the new SRS version.

DHtLCC)._O ;_ D CORPORATION

2-8

Space & I=le_ntry

Systems Division

TR-DAI522A

SECTION 3

EVALUATION TESTS

3.0 GENERAL

A major part of the Phase II effort was spent in a test program with the

purpose of evaluating and isolating the causes of S-band carrier phase shift

and ranging delay variation in the Mariner C transponder, as a function of

temperature. The transponder used was JPL-supplied; a list of pertinent

serial numbers is given in Table 3.0-I.

In addition to these tests, specific diagnostic tests were performed on

several of the modules of the above mentioned JPL-supplied transponder.

A block diagram of the Mariner 'C' transponder is presented in Figure 3.0-1,

and is intended for general reference purposes for the various sections of

the report.

3.1 TRANSPONDER OVERALL S-BAND/'_CO"/RANGING PHASE VERSUS TEMPERATURE

The transponder was connected in a normally operating condition for each of

these tests, and the various component parts of the transponder were separ-

ately subjected to temperature variations, with all of the remaining compon-

ent parts held at constant temperature. The test set up block diagram is

shown in Figure 3.1-I. As shown in this figure, a transponder (REFERENCE

TRANSPONDER) similar to the subject transponder (TEST TRANSPONDER) was held

at constant temperature and used to provide stable phase coherent reference

signals for the measurement of the S-band and '_CO" phases. The reference

and measured signals are taken at corresponding points in the two transponders.

The major points of interest are listed for convenience as follows:

• S-band phase shift is the carrier phase shift of the 2295_z RF

output of the Exciter, relative to the S-band reference signal.

The data at +25°C is used as a reference point. In effect, this

measurement is equivalent to an S-band input to output overall

transponder phase measurement.

3-1

• DHtLCO-_O_O CORpOrATION

; Sp_ce _- R_-entry

Systems [Division

TR-DAI522A

No.

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3.

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5.

6.

7.

8.

9.

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12.

13.

14.

15.

16.

JPL -

Table 3.0-I

Supplied Transponder Serial Numbers

Identifying Name

Preselector

Mixer-Preamp Module

47.8 Mc I.F. l_mdule

9.56 Me I.F. Module

X36 Multiplier Module

AGC Detector Module

Phase Detector Module

VCO Module

Frequency Divider Module

Isolation Amplifier P_dule

Video Amplifier Module

Auxiliary Oscillator Module


Receiver, Six Pack No. i

Receiver, Six Pack No. 2

Exciter, Six Pack

15

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(obscured)

4

4

4

4

4

5

5

4

8

21

4

4

4

The following units were also supplied, but were notused in the tests.

17.

18.

19.

20.

Auxiliary Oscillator Module


Power Supply

Power Supply

7

14

3

5

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• Two quadrature-related measurements are used in order to avoid

ambiguity and provide greater accuracy in the S-band phase readings

(S-band pha_e shifts typically exceed 90 degrees for each tempera-

ture increment).

• "VCO" phase shift is the phase shift of the 19-1/8 MHz VCO

output signal (i.e., the exciter input drive signal) relative

to the '_C_' reference signal. In effect, this measurement

is equivalent to an S-band input to VCO output overall receiver

phase measurement.

• The ranging delay measurement technique is based upon comparing

the phase of the fundamental component of the delayed 498 KHz

ranging signal with a reference signal in the test set. See

Figure 3.1-2 for further details. Note that the reference

transponder is not involved in the ranging measurements.

Further information on test methods and procedures is presented in

Appendix VII. A llst of pertinent serial numbers for the test set are

presented in the appendix; Table A.7-1.

In the tests to be described next, the temperature increments were,

in the order taken:

a. -10°C e. +40°C

b. 0°C f. +50°C

c. +10°C g. +60°C

d. +25°C h. +75°C

S-band and "VCO" phase data were taken at input signal levels of -70 to

-140 dbm in I0 db steps, and ranging phase data were taken at -70, -90,

and -II0 dbm.

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The order of the temperature tests were as follows:

a. Entire Transponder

b. Individual Six Packs (3)

c. Individual Modules (13)

The results of these tests are presented next. The module arrangement

within the six-packs is shown in Figure 3.1-3 for reference purposes.

3-7

P_ILCO-FORO CO_PO_ATJON

Space _ Re-entryE_ys1=em9 Division

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PHILC:O-FORO CORPORATION

3-8Space I_ Re-entrySystems Division

_'3

TR-DAI522A

3.1.1 Entire Transponder Evaluation Test

/

Figure 3.1.1-1 indicates that, in the case of the entire transponder, the

S-Band phase shifted fairly linearly with temperature. The total varia-

tion throughout the temperature range is 22.2 cycles. This large phase

shift is the result of many small phase shifts resulting from circuit

detuning which are multiplied by various factors in the frequency multi-

pliers. Figure 3.1.1-2 is the phase shift measured at the VCO signal

input to the Auxllary Oscillator module. Since the Exciter Six Pack

multiplies this frequency (and therefore phase variations with temperature)

by 120, the total VCO shift noticed in this figure can be used to deter-

mine what portion of the total S-Band phase shift was caused by the

Receiver Six Packs. In this case, the total VCO variation of 40.3" multi-

plied by 120/360" equals 13.4 cycles variation at S-Band. The remaining

8.8 cycles variation was caused by the Exciter Six Pack.

The values for the VCO phase shift were read directly from the Wiltron

phase meter. Since the transponder will lock to the incoming signal at

many different VCO phases (see Section 4.2.3), only the relative shift

with temperature should be considered. This explains the difference in

the absolute value of VCO phase shift that will be noticed in these

graphs in the following sections.

As seen in Figure 3.1.I-3, ranging delay did not vary linearly with temp-

erature. Most of the ranging delay variation was determined to be caused

by the subsequent misalignment between the reference and the signal at

the ranging detector as temperature varied (see Section 4.1.2).

Figure 3.1.1-4 and 3.1.1-5 show the comparison of S-Band phase shift and

ranging delay variation measured directly while the entire transponder

was under test and the sum of the data measured while the individual six

packs were under test. The contributions of each module toward these

variations are quite dissimilar in direction and magnitude. This means,

3-9

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since there is good correlation between the data from the entire

transponder and the sum from the six packs, that the delay variations are

a result of many cancelling effects.

Ranging delay was also noticed to vary as a function of input RF attenua-

tion. In most cases, the delay becomes shorter as the input RF level is

decreased. This is probably the result of the reduction in the 498 KHz signal

content as the S/N ratio is decreased. Separate ranging delay tests show

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Video Amplifier (see Figure 3.2.2-8).

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DB of RF input attenuation. The S-Band phase shift divided by 120

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by the receiver portion of the transponder.

Each time the temperature of the test environment was changed, a minimum

of one hour was allowed for stabilization. In thirty minutes, essentially

complete stabilization was noticed to have occurred.

3.1.2 Six Packs Evaluation Tests

Figures 3.1.2-1, 3.1.2-4, and 3.1.2-7 show the change in S-Band phase as a

function of individual six pack temperature changes. Figure 3.1.2-1

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two six packs. HowevEr, its contribution to phase shift is small, onlyl

+4.55 cycles total, Compared with the contribution of the other six

packs, -17.78 cycles for the Receiver, Six Pack No. 2 and -9.48 cycles

for the Exciter Six Pack.

Figures 3.1.2-2 and 3.1.2-5 show the VCO phase shift as a function of the

receiver temperature. The total deviation indicated in these graphs will

equal the S-Band phase shift for the respective six pack when multiplied

by 120/360". This is natural since the VCO phase shift represents which

portion of the S-Band phase shift was caused by the receiver, and the

receiver was the only portion undergoing temperature test at this time.

There is no VCO phase shift for the Exciter Six Pack because the receiver

didn't contribute any of the S-Band phase shift at that time.

Figures 3.1.2-9 through 3.1.2-16 show comparisons between data measured,

while individual six packs were in the oven and the sum of the data

measured while the respective six pack's modules were in the oven. The

sum of the data from the modules correlates fairly well with the data from

the six packs. The variations are believed to be due mainly to interaction

effects between modules when the individual six packs were being tested.

Again, each time the temperature of the test environment was changed,

stablllzatlon was essentially complete in thirty minutes and a minimum of

an hour was allowed.

• 3.1.3 Modules Evaluation Tests

The graphs in this section are presented in a similar manner to those in

the previous section, that is the S-Band phase variation first, the VCO

phase variation next, and then the ranging delay variation. The main

dlffere_ce is that a separate set of graphs was not made for each module.

Rather, the modules were grouped for convenience and comparison between

modules. The order of presentation then is a set of S-Band, VCO, and

3-32

I l!Jpl,.ll LCO.FOR D CORPORATION

Space & Ro-entrySystems Division

TR-DAI522A

ranging comparison graphs of the modules for each of the three six packs.?

Figures 3.1.3-1, 3.1.3-4, and 3.1.3-7 show the S-Band phase variation

associated with the temperature change of each module of the transponder.

The X36 Multiplier is responsible for nearly all of the S-Band shift of

the Receiver, Six Pack No. I, except the X36 Multiplier will appear at

S-Band in the ratio of 240/221. Phase shifts originating in the X36

Multiplier will appear at S-Band in the ratio of from 240/221 to (36)

(240/221) depending on where in that module the phase shift occurs.

(See Appendix V and Figure A.5-1). Note that the phase shift caused by

the X36 Multiplier is opposite in slope to that of the entire transponder.

This agrees with the data taken for the Receiver, Six Pack No. I (Figure

3.1.2-1).

The VCO Module caused most of the S-Band phase shift for the entire

transponder varying a total of 12.96 cycles. This is because phase

shifts appearing at the output of the VCO Module are directly multiplied

by 120 before appearing at S-Band. The contribution to S-Band phase

shift caused by the Frequency Divider is believed to be due to input

impedance changes effecting the phase at the output of the VCO Module.

Again, these changes are multiplied directly by 120.

The two modules of the Exciter Six Pack contribute about equally to the

S-Band phase shift. Phase shifts originating in these modules appear at

S-Band in a ratio of from I:I to 120:1 depending on where in the modules

the phase shift occurred.

The VCO phase shift for the modules of the receiver six packs (Figures

3.1.3-2 and 3.1.3-5) agree closely to the S-Band phase shift for those

modules when multiplied by 120. The modules of the exciter didn't effect

the rece%ver phase shift and so no graphs of VCO phase shift are in that

group.

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Comparing the ranging delay variation graphs (Figure 3.1.3-3, 3.1.3-6, and

3.1.3-8) with the S-Band phase shift graphs for these modules (Figures

3.1.3-1, 3.1.3-4, and 3.1.3-7) it can be seen that there was no smooth

relationship between the way the S-band shifted with temperature and

the way the ranging delay varied. Most of the delay variation for the

transponder was caused by the 9.56 MHz I.F. Module, which isn't in the

ranging loop. However, because of an unusual effect of the ranging

phase detector, carrier shifts occurring in this module result in signi-

ficant video phase shifts (see Section 4.1.2).

The Isolation Amplifier caused most of the ranging delay variation in the

Receiver, Six Pack No. 2. This variation was due to the same effect as

observed in the 9.56 MHz I.F. Amplifier. This effect is the result of a

shift in phase between the signal and the reference at the ranging

detector.

The contribution to ranging delay variation caused by the Frequency Divider

is due to this same ranging detector effect. This indicates again that

most of the ranging delay variation is caused by the unusual operating

characteristics of the ranging phase detector.

The only module which apparently had a significant contribution due

to group delay was the X30 Multiplier.

Figures 3.1.3-9 through 3.1.3-19 are S-Band phase and ranging delay graphs

of specific module tests. They are presented to give a better view of the

phase shift and delay variations caused by those modules which had signif-

icant effects. The S-Band graphs are usually shown on a larger scale than

the combination graphs noted previously. The ranging delay graphs show the

effect of R. F. power level changes into the transponder during the testing

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of those modules which contributed most to ranging delay variations.

These graphs are useful for more closely observing the major S-Band and

phase delay contributions.

Stabilization was noticed to be essentially complete after twenty minutes

from the time of temperature change. As a result of the faster stabiliz-

ation for the modules, only a minimum of forty five minutes was allowed

between temperature points.

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3-54

p_| LCO.ItO R D CORPORATION

6pace & ReentrySystems DtvislQn

TR-DAI522A

3.2 DIAGNOSTIC TESTS

In order to better understand the effects producing ranging delay

variations, several tests were made in addition to the evaluation tests

in the previous section. These additional tests, described in this

section, were tests made on modules removed from the transponder system.

They show the characteristics of some of the modules which produced the

most delay variations.

3.2.1 Module Tests

The first module to be investigated separate from the transponder system

was the 9.56 M}{z I.F. Module. The block diagram showing the setup for

the testing done on this module is shown in Figure 3.2.1-10. As can be

seen, the crystal filter was disconnected from the module to allow

measurements to be made with and without the crystal filter.

Figures 3.2.1-1 through 3.2.1-5 show the phase and amplitude as a function

of temperature. The phase variation with temperature for both the linear

and limited outputs of the 9.56 Mllz I.F. Module differed only slightly

between the crystal filter connected and disconnected.

However, the absolute phase shift through the I.F. Module was changed

considerably with the crystal filter added. The linear to limited phase

shown in Figure 3.2.1-4 shows about a 50" variation with temperature.

This means, since the transponder receiver locks to the limited output,

that the AGC detector becomes rather badly mlsallgned as the transponder

changes temperature. The specification for linear to limited phase shift

over temperature is ±15".

Figure 3.2.1-5 shows that the gain roll off for the linear and the

limited output of the 9.56 MIIz I.F. occur at opposite temperature limits.

3-55

IpHILCO I_DHILCO-_ORO COmp_RATION

BpaQe & Rm_ntrySystems Division

TR-DA1522 A

The amplitude and phase response of the 9.56 MHz I.F. Module shown in

Figures 3.2..1-6 through 3.2.1-9 were obtained with the test setup shown

in Figure 3.2.1-10. These measurements were made at room temperature.

The graphs indicate that the phase and amplitude response of the 9.56

MHz I.F. is normally almost entirely determined by the very narrowband

crystal filter.

Phase and amplitude response measurements were made of the I.F. stages of

the 9.56 MHz Isolation Amplifier. In order to facilitate this test, a few

minor changes had to be made to the module. Figure 3.2.1-12 indicates the

changes made for the phase measurement. Fifty ohms were added to the

emitter of the emitter follower so that a small sample of the signal

could be monitored for this measurement. This prevented the phase meter

from loading this stage. The signal then had to be amplified to permit

phase measurement with the Wiltron.

Being a high impedance meter, the Boonton RF voltmeter was used to monitor

the output of the emitter follower directly, Figure 3.2.1-14. This

permitted an absolute gain measurement of the I.F. stages of the 9.561dHz

Isolation Amplifier. The results of these tests are shown in Figures

3.2.1-11 and 3.2.1-13. Note that although the amplitude response changes

only slightly with temperature, the nominal gain varles by about 17 DB.

Figures 3.2.1-15 through 3.2.1-21 show the phase and amplitude character-

istics of the Frequency Divider Module. Although conslderable phase

variation occurs with temperature, the phase relation between the three

outputs of this module remain essentially constant which should mean

that the reference to all the detectors maintains alignment. Actually,

although not shown on the graphs, there was a variation of from 2" to 5°

between 33 and J4 over temperature. This slight misalignment of the

ranging phase detector accounts for some of the ranging delay variation

with temperature.

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Space & I::le-en_;rySystems Oivision

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Figure 3.2.1-13

-lO°C

25°C

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FREQUENCY (MHz)

Amplitude Response of the 9.56 MHz Stages of

the 9.56 MHz Isolation Amplifier at Several

Temperatures.

The Gain Specification is + 3 db Over the

Temperature Range of -10°C--to +75oc.

iP.L=oI III H I I.CO -F O I:_ D CORPORATION

3-69


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i--,-co :.....]I_HII_O-PC) N_) _ONWONATION 6paoe & Reentry

8ymtems Oivi,,Ion

TR-DAI522 A

Output power is shown as a function of input power for the three

Frequency Divider outputs in Figures 3.2.1-17 through 3.2.1-19. The test

setup for the measurements made on the Frequency Divider is shown in

Figures 3.2.1-20 and 3.2.1-21.

3.2.2 Special Tests

Tests were made to see what effect reflections from the 9.56 MHz Crystal

Filter had on the signal from the 47.8 MHz I.F. output to the Isolation

Amplifier. Figures 3.2.2-1 through 3.2.2-7 are all associated with these

tests. Figures 3.2.2-1 and 3.2.2-2 show the amplitude and phase response

measured by the test setup shown in Figure 3.2.2-3. These graphs are

plotted with an unusual frequency scale to show a detailed view of small

frequency deviations and at the same time permit plotting of large

frequency deviations. These figures indicate that with ample isolation

between the 47.8 MHz I.F. and the 9.56 MHz Crystal Filter, very little

amplitude and phase variation would be observed in the ranging channel.

Table 3.2.2-1 was made from the graphs of Figures 3.2.2-1 and 3.2.2-2 by

considering a modulation frequency of 500 kHz.

Figure 3.2.2-4 shows the results of the test made in Figure 3.2.2-5. This

test was a normal ranging delay test of the transponder with the phase of

the reference to the ranging phase detector as the independent parameter.

Figure 3.2.2-4 shows that the slope of the curve of ranging delay vs

reference phase can be greatly reduced by isolating the 9.56 HHz crystal

filter from the 47.8 MHz I.F. output to the Isolation Amplifier between an

isolated and non-lsolated 9.56 MHz cyrstal filter.

Figures 3.2.2-8 through 3.2.2-I0 show the effects on ranging delay due to

mlscellaneous factors. Figure 3.2.2-8 shows the effect on ranging delay

due to dlmlnishlng the slgnal level to various modules. It should be

noted that in modules such as the Video Amplifier, the attenuator reduces

• signal and noise together thus maintaining a constant signal to noise

ratio. Temperature variation of the transponder may change the signal to

3Ilkil I.(;0. P D It D GI)RPORATIDN

3-78

Space & RemntrySylteml [31vision

TR-DA1522A

noise level in some of the modules and therefore change the shape of

some of these curves in actual operation. The signal level input to the

modules shown is not expected to change nearly as much as the variations

used in this test.

Figure 3.2.2-9 shows ranging delay variation as a function of several

unrelated factors. Modulation level of the up-link signal is seen to

have little effect on ranging delay. Power supply variations on the

other hand have a significant effect. During all testing here, the

transponder power supply voltages were monitored and observed to be very

well regulated. However, this test shows the importance of well regulated

supplles being used in the space craft. The SPE offset curve was measured

by changing the test transmitter frequency to obtain a SPE. Because of

this change in frequency, the curve shown is not Just an effect of SPE

as would occur if the transponder VCO crystal changed nominal frequency

with temperature, due to the phase characteristic of the crystal filter.

Figures 3.2.2-11 through 3.2.2-18 are concerned with spurious levels

within certain modules. Figures 3.2.2-11 through 3.2.2-14 are shown

mostly to illustrate the effect of the f/4 harmonic of the VCO frequency

when it is generated in the Frequency Divider module. It can be seen

that when generated, the f/4 harmonic goes right through the video

amplifier with considerable amplitude. The important thing to note from

the spectrum pictures is that the magnitude of the f/4 harmonic was with-

in the JPL specification limits for the Frequency Divider module. It was

discovered that careful tuning would eliminate this harmonic. It was

noted that the ranging delay vs ranging detector reference phase (Figure

3.2.2-4) showed an increase in slope ofl.5 times with the f14 harmonic

being generated (this result is not graphed). Thus, the importance of

tuning the Frequency Divider not to within spurious specification, but

for the elimination of any f/4 harmonics can be seen.

3-79

_NILCO-PORO CORpORAT)ON

Bpace & ReentryBystems Divl,,don

TR-DAI522A

Figures 3.2.2-16 through 3.2.2-18 show the output spectrum of the

Frequency Divider with the f/4 harmonic eliminated. Figure 3.2.2-15

is a time waveform of the video signal at the output of the Isolation

Amplifier when the Frequency Divider was not generating a f/4 harmonic.

Note here the large 9.56 MHz component of the video waveform even during

normal operation of the transponder.

Figure 3.2.2-19 is presented as extra useful information. It shows how

the harmonic content of the 9.56 M}{z I.F. varies as a function of reduced

input signal.

A 400MHz spurious (not shown) was also observed but did not appear

to affect the various test results. A slight power supply voltage

reduction was noticed to eliminate this spurious.

t.

3-80

mpaoR & Reentry8ymtmmm Divlalon

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3-83


TR=DAI522A

TABLE 3.2.2-I

EXPECTED RANGING SIGNAL SPECTRUM DISTORTION

DUE TO CRYSTAL FILTER INTERACTION

SIDEBAI_ FREQUENCY AMPLITUDE (db) PHASE (Deg)

fo " 4 fm +1.6 -14

fo " 3 f +1.2 -18m

f - 2 f +0.6 -22O m

fo " f -2.1 -I0m

fo 0.0 0

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fo + 2 f +4.0 -9

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NOTES:

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2.

3.

fm " ranging modulation frequency

f = 9.56250MHzo

The AMPLITUDE and PHASE values shown above were taken

directly from Figures 3.2.2-I and 2. The ranging spectrum

is altered from normal values by the values shown.

3-84

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SCALE: 498 KHz_ 17 MINOR DIVISIONS

Figure 3.2.2-6a Normal 9.56 MHz Ranging Signal

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Figure 3.2.2-8 Ranging Phase Delay vs Attenuation of the Normal

Power Levels to The Modules Indicated.

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TR-DAI522 A

F _ _ m M m u _ m I

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I ,"-,L_oJi.;-:J_PHILCO-_QRO CORPORATION

Figure 3.2.2-I0 Method of attenuating the Input to

Modules to Determine Delay vs

Input to Various Modules

3-91


TR-DA1522A

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Figure 3.2.2-ll Spectrum of X½ output to Ranging Phase Detector Due

to improper alignment of the Frequency Divider. Note

the presence of _F harmonics. The harmonic content,

although troublesome, met JPL Specs. (F = 19.125 l_z)

Note 1:

Note 2 :

The alignment condition became evident after changing the

number of turns of one of the toroids in the divider, so

as to achieve stable divider action over the required

temperature range. The unit was subsequently aligned sotha_ the f/4 harmonics were absent.

All the data shown in this report is Eor the properly

aligned case. except where so noted.

3"92

l'H'L=ol3 Space & R e.-entry

_-DA1522A

• ii!!!_iiil!iiii!ii.l ii ilil! ii! ii]iil !iit

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3-93

_H|_|_PORO CORPC) R&TION

Spa_e & I_e_entry

Systems Division

TR-DAI522A

DBM

o-F--i

-10-

i

-20 --

-30 -

[

-40 -

-50-L ............

f/4

Figure 3.2.2-13a

f/2 3f/2 f s£_4 3f/2 7f/4

Video Amplifier Spectrum with Transponder

Locked to Test Set but no Modulation; X½

Improperly aligned

DBM

-I0--[

-20 -!_

-30 -

i:

-4O-!:

-50-- : !:i!, i

t : "_-_ _ "

f/4 f/2 f/4 [ 5 t/4 .-it/z

Figure 3.2.2-13b Same as above but with 9.56 MHz Filter Inserted

in REF to ISO AMP in Transponder.

3-94

"[ PHILCOSpace r., ICle-entrv

TR-DAI522A

Figure 3.2.2-14a Output of Video Amplifier. Scope Synced to 498 KHz

Clock from Code Monitor Panel. Pin = -70 dbm, with

Ps = 9 db. The X% was Improperly Aligned: Note

4.78 MHz Content.

]

Figure 3.2.2-14b Same as above, but with 9.56 MHz B.P.F. in the

Reference Leg of the Ranging Phase Detector.

3-95

i pHILCO l_ Space & P e.-entry

YR=DA1522A

............ _ .%_T_=L_-_" "_•_: _%__"_ " _- ........ • ................ ._ ,, .... =_.

Figure 3.2.2-15 Upper Trace:Lower Trace:

Condition:

Input to the Video Amp1.

Output of the Video Ampl.

Normal

Note: The Photos are Intended to Show the Large 9.56 MHz

Content Which is Normally Present at the Input to

the Video Amplifier (X½ Properly Aligned).

3-96

Space & ;_e-entry

TR-DAI522A

410.0

0.0

-!0.0

Emn

zm

_. -20.0DnPDO

n,Ld

-3o.o0n

-40.0

-50.0

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i

. . . . .

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I

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i

i..... ...... t

I

1

t

I

_ f f 3f 2 f 5f2 2 2

SPECTRUM ( f = VCO FREQUENCY)

Frequency Divider. Frequency Spectrum For 3 2 Output(_C),

3-97

. IIHILCO-FORD _ORPO;_ATIONSpace ¢ Re-entrySystems i'_ivision

TR-DA1522A

-_!0.0

0.0

-!0.0

:£ -20.0mD

Zim

I'-Dn

I-D -30.0O

hl

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-40.0

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_f f 3_f 2 f

SPECTRUM (f = VCO FREQUENCY)

• Figure 3.2.2-17

i

i •i

]_.__L___

i " "

i

Frequency Divider. Frequency Spectrum For J3 Output(¢ DET).

IIH I LC; 0.1¢0 R (:1C Oli PQ I_iA, TI (;I N

3-98


TR-DA1522A

[]O

z

D

DO

n,hl

+I0. O.

0.0

-I0.0

-40.0

-50.0

-60.0

" ; " " ; ; , L . " " " ' : , " " "

..... " L i _ ! _ , ; ! _ • 1 ; _ ! i i , ".......... : ' - -! .... ._...... I ,-,4-. _-_-,. ;4 .--,+,-_---_-1.i _.--_-,-: L-_

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....... t ......... t • _ + , _ _---_ .... -. _-..... _ • _..... ; . ._ . , , ,..i ..... _.... _, , +.-_-_ . i- ': i , _ .... . . . .

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.... __'_.

" " I i ij', "i':'i J:'r: ""?Ti'': ..........

If If 3_f 5_f 3 f 7_f4 2 4 f 4 2" 4 2f

SPECTRUM (f = VCO FREQUENCY)

Figgre 3.2.2-18 Frequency Divider. Frequency Spectrum For J4 Output(_SO AMP) .

3-99

I,--,-=o li JIBNILC(_II_R O COR _(_ RATION


TR-DAIS22A

//L/

mrl

I-DO.I-D0IZ

hi

0o.

+15

+I0"

-I0

-20

-30

......_ ..... lt .................! " " " ' _" " , _, , , _ , . F

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4 ..: ............ ; , i:

F _ _-| ........ ! .... _ . . ._5_-_ .. ...... t" ...... : ...... I

L. _ " !;' ........ ! ...... ,_i .... ii " J ' • _ i .... Y

7 i !ii! iJi!! !-! l!i?!i::: ',il i ......... 6

-i .... I ........ i ....... ' ...... i

-86 -81 -78 -76 -74 -71 -66

POWER INPUT (DBM)

Figure 3.2.2-19 Power Output vs Power Input of the Fundamental

and Harmonics of the 9.56 MHz I.F. AmplifierModule.

IPH,LCoIIHII.CO-IIORI3 I:ORPORATION

3-I00


TR-DAI522A

SECTION 4

ANALYSIS AND STUDY

4.0 GENERAL

The principal goal of the analysis and study effort was to relate the

ranging delay and S-band phase temperature data to transponder circuit

functions. In addition to this, a study was made to determine the optimum

transmit-to-receive frequency ratio, from the transponder viewpoint, for

the proposed change in the DSIF band occupancy.

4.1 RANGING DELAY AND RANGING DELAY VARIATION

The various measurements made in the program, combined with the analysis

efforts indicate that:

a. Group delay in RF stages due to bandpass interstage coupling net-

works, and phase shift of the fundamental component of the 498 KIIz

square wave in video stages, is responsible for almost all of the

measured ranging delay time in the transponder. These are normal,

unavoldable delay phenomenon and result mainly from bandwidth

limiting requirements.

b. Ranging delay variations measured in the JPL transponder are

produced principally in the demodulation process, and are caused

by variations in the reference phase relative to the carrier.

This phenomenon can be corrected to acceptable limits.

The delay produced by interconnecting coaxial cables and module wiring is in

the order of tenths of a nanosecond per inch, and hence are not considered

significant for analytical purposes. The delay due to the active elements

such as transistors and diodes is in the order of tenths of a nanosecond

per unit ....

A functional block diagram of the ranging loop is shown in Figure 4.1-1. A

summary of the measured and the expected ranging delay and ranging delay varia-

tion data is presented in Figure 4.1-2.

4-1

PHIL(_O.leO m O _ORPORATIQN

Space _- ReentrySystems [::)ivision

U

<

m

<

OF-

WI-

ONI--0

O×

I_lt.C_lcOR 0 COR PI:RATIQN

.

4-2

TR-DA1522A

OO>

:EOn,t,

×


. TR-nAI522A

m

!b_

4' z

^ #_ _ • .,_ • ..: • .,_ ,_ .......... .÷ _ _ _ , _ + _ _ , , _-, -,_-- ,_-._ ._I.-._ _ ' '.__.o_o:o o o o ° o o.., o

• • i • ¢_ _ • • t • _ • • , • • • , • , • , •

• ,,a

..: ,,; ,_ _ _ ,_ ,._,_ _ i¢_ • •

6-3

v

= =

• • • ° °

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, + ._

11 .

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_ _ _. _ ,+_= ®_

_ _ _ ,_ _ ..,-__ _ _ "_ _ ";.,

_ _._ii ,

IrPN'LCOI p_ll I_¢O*FO R r_ I_rl RPO RATION

Space & Re-entrySystems Oivision

TR-DA1522A

4.1.1 Ransing Delay and Ran_in_ Delay Variation,

Due to Interstage CqupllngNetworks

A module-to-module analysis was performed In order to obtain calculated

values for nominal ranging delay,and ranging delay variation due to inter-

stage coupling networks so that expected and measured data at normal operat-

ing temperatures and temperature varying conditions could be compared

dlrectly when possible. The overall transponder expected ranging delay

and ranging delay variation due to Interstage coupling networks is then

taken to be equal to the sum of the Indivldual module values. Three simpli-

fying assumptions are used in the analysis:

a. The interstages are either of three types; 1-pole bandpass or

low pass, or 2-pole Butterworth bandpass

b. Similar interstage types in each module can be grouped

together as m identical n-poles.

c. The ranglng signal is not coded. (Measured rangln E delay

change from code ON to code OFF was -25 nanosecond at PIN = -90 dbm).

In computing the expected nominal ranging delay for each module, the

pertinent data was obtained from the "Transponder Parameter Summary" given

in Table 4.1.1-1.

The expected ranging delay variation due to insterstage coupling networks

was computed on the basis of group delay variations in RF stages. This was

done by relating carrier phase shifts in the interstage to circuit detuning,

and then relating group delay variations to the circuit detuning. Thus a

relatioship was established between measured carrier phase variations and

expected ranging delay variation.

Expressions were derived for nominal group delay and group delay variations

as a function of circuit detuning. These are presented in Appendix I and

were used in the calculations which follow.

• pMILCO.FOnO CORPORATtDN

4-4

Space & ReentrySystems Oivis|on

/(? +i

Table 4.1.1-1

TRANSPONDER PARAMETER SLP_4ARy

TR-DAI522A

_D_E

RANGING LOOP

Preselector None 5-Pole Cavity

Mixer Preampl. 4 Transistors 2-pole

1 Diode Pair (Mixer)

47.8 IF & 2rid 8 Transistors 2-poleMixer 1 Diode Pair (Mixer)

IsolationAmpl. 7 Transistors 1-Pole

1 Diode Pair (Detector) 1-Pole

Video Ampl. 4 Transistors 1-Pole

2 Diode Pairs (Llms.)

Aux-Osc, Mod.&X4 2 Transistors 2-pole

1 Diode Pair (Mult.)

X30 Multiplier

INTERSTACE

Type i No.(n-pole) (m)

Bandwidth

TOTAL per

BAND_qDTH Seage

(sn)

4 Transistors


2 Diodes (Multa.)

2-pole Cavity

1-pole

2-pole

4

4

2

4

2

1

4

3

30 MHz (1) 30

8.1 MHz (2) 11.4 MHz

12.0 MHz (2) 18.2 MHz

8.0 Mltz (6) 18.2 )_z

2.1 MIIz (4) 3.28 HHz

3.3 MHz 7.50 MHz

(5) 6.45

(3)

2.5MHz(5)(2) 22.7 M_z (4)

6.45 _z (4)

9.56 MHz IF

(J30utvut)

X36 Multiplier

ACC Detector

Phase Detector

vCO & X3 Multiplie

(J4 Output)

Frequency Divider

(J3 Output)

Aux. Ose.,Mod. &X4

7 Transistors

2 Transistors


2 Diodes (Mults.)

4 Transistors

3 Transistors

I Diode Pair _ult.)

1 Transistor

2 Diode Pairs (Switches)

OTHER

2-Pole 1

X-TAL Filter

2_P01e 5

2-pole Cavity I

_11-j)ole ..... 3 _

2-pole 2

l-pole 1

2-pole 4

1-pole 22-pole 3

2-pole 2

4.90 KI_ 4.90 l_z

600 lqHz 968 MHz

(3) (3)(3)(3),

(3)

(3)

(3)

(3)(3)O)(3)(3)

NO'_'3: 1. Specification value

2. JPL - supplied data for S/N 4 transponder, dated 1964.

3. Data not known

4. Interior ensineerin g report values

5. Composite Aux-Ose And X30 value

6. Extrapolated value

All other data is contained in this report.

4-5

I PHILCO _ Soa=e&Re-_ne._

TR-DAI522A

Refer to Figure A.I-I which is a plot of phase shift and fractional

change in group delay vs relative detuning, for one-pole and two-pole

Butterworth bandpass Interstage coupling networks.

Tank circuit overall temperature coefficients can also be deduced from

carrier phase shift data through the formulas presented at the end of

Appendix I. This could not be done however, in the allotted budget.

The results of the computations which follow are tabulated in the "Ranging

Delay and Ranging Delay Variation Summary" given in Table 4.1-2.

Preselector

lo7j A dj = phase slope at

= dw oQ

Using the Bode approximation for phase slope,

.

(2,) (30x106 rad/sec)

vd _ 40 nsec

This simplified model does not show the change in phase slope

for deviations from band center which actually are present in

a Butterworth filter, so that delay variations cannot be shown

from this model. However, the variations should be nil, since

the carrier phase shift over the temperature range is nil.

4-6

IP-,L=oPH_L_O-_O_O CORPOAATION

Space & Re_sntrySysternm Division

TR-DA1522A

Mixer-Prea_p

le

7 ¸

/

"d = m_n = .total nomlnal expected group delay

" (no. of Interstages)(delay per interstage)

2J-F"d" 3"2" 3(--2% > seo

where B2 is the bandwidth per 2-pole Interstage in hertz.

"d" 3¢ J__xll"4xlO" 6 ) " 3(39.4x10 "9) " 118 nsec

2. A,d = mAVn = m(Vn) (An) - total expected group delay variation

o)(,2)(_) - ,d(+ 1/2 el)

where _2 is the carrier phase shift per 2-pole interstage,

in radlans.

=_= total carrier phase shift due to temperature_2 m No. of Interstages

:" &Vd _= + ('d 1/2

Since

.221.&8 < • (2_) (0.01) (2_) tad

_'d < + (118)(½)(5"77; 10"2)2 - +0.I0 nsec.

4-7

IP.,Lco.]!7PHIl.CO-FOR D CORPORATION

Space & IRe-entrySystems Division

TR-DA1522 A

47.8 t4Hz IF

,

e

Td = 4_2 = 4( 0.4518.2x10" 6 Isec

" 4(24.7 x 10 -9 ) = 99 nsec

I+29.81 2A7d(- AV) = +(99 nsec) (1_) 57.34 7

" +0.8 nsec

where -A7 signifies that the carrier phase shift, and hence the

group delay variation, occurs in the temperature range below

+25°C.

L n_(-nv) j

.-46.4. 2= +(0.8 nsec)(+2--_--_.8) ffi +1.8 nsec

Isolation Amplifier

I. _d = (_d)RF + (_d)vld

2

-4( 0.3_8 )-4c17.s _ _0"9)- 70_.eo18.2xlO" 6.

= nse% (Ael)(Td)vi d (m) (320 r-"ad--;

- total delay of fundamental component (i.e., 498 KHz)

4-8

iPH,.col jDM ILCO-FI_IqO CD R P(:] RATION

15pace & ReentrySystems Division

TR-DA1522 A

Ae I . tan-l( 498 KHzfl )rad

= phase delay of fundamental per Interstage

498 KHz 498x103ffi - 0.152 rad

fl 3.28x106

nsec_l O(md)vl d = (2) (320 r--_-'" "152 rad) = 97 nsec

Cd " (70 + 97) = 167 nsec

2. _Td = (ATd) RF + ( ATd)vid

But due to lack o£ phase shift versus temperature data on the

video portion, only the delay variation (ATd)RF was computed.

/ +16.6___.__2

_d(-_T) "-(70 nsec) _ 5_.3_

- -0.5 nsec

13 o 2

_Td(+A_) - -(0.5 nsec)C

+16.6 J

" -0.05 nsec

4-9

i-H,Lco]F3PH|LCO._OR(_ CO_I PO_IATION


TR-DA1522A

Video Amplifier

Io 7d = (m) (320 nseC_rad,(AS1)

498X103nsec_(4)(320-f ad (

7.50x106

(4)(21.3 nsec) = 85 nsec

2. ATd was not computed, due to lack of phase shift versus temperature

data.

• k

°"

i'!.

.L

Auxi.llary Oscillator

I. 7d 2"r2 2(0''450 )m = sec

6.45x106

= 2(69.6 x I0-9) = 139 nsec

+28.8

2. A7d(-AT) " +(139 nsec)(1) [ 57.32

= +4.4 nsec

.,/-32.4A7d(+AI") = +(4.4 nsec7_,_._ _J

= +5.5 nsec

X30 Mu.lt!p1.1er

2

Io

7d " (Td)l.pole s + (Td)2.pole s

(Td)l.pole s = 471 - 4 _20,r318.7xi06) sec

= 4(14.0 x 10.9) " 56 nsec

4-10

pHIt.CO._ORO COrn mORATION

Bpa¢e & ReentryBystems Divislun

(_d)2.poles = 3v2 = 3(. 0.450 ) sec6.45xi06

ffi3(69.7 x 10"9) = 209 nsec

vd - (56 +209) = 265 nsec

2. d - (A,d)2.pole s

I+ 677 ,_ 230x57.3)A_d(-AV ) = +(209 nsec)( ) 3

= +1.8 nsec

(-900)2e_d(+A_) = +(1.8 nsec)

- +3.2 nsec

TR-DAI522 A

The expected total nominal ranging delay due to interstage coupling

networks is 913 nsec. Adding about 5 nsec for all the active elements

brings the final total to 918 nsec. That this figure is higher than the

measured value by about 17Z is not too surprising, since the second assump-

tion at the beginning of thls section would tend to cause a cumulative error

on the increased delay side. This follows from the fact that the narrowest

interstage dominates the overall bandwidth of a group of similar inter-

stages, and that all but the narrowest Interstage is then over-charged in

the group delay.

However, this effect is somewhat compensated by two cavity filters (see

Figure 4.1.I-i) which were neglected in these calculatlons, due lack of

data.

The expected -AT and dr ranging delay variations due to RF Interstages

is -I-6.5 and +10.5 nsec, respectively.

4-11

IIH II.CO.l[OmO CORPOmATION

Space & RemntrySystems Division

TR-DA1522A

Comparing these flgures to the measured values indicates that the nomlnal

group delay is due toithe Interstage coupllng networks but that the

measured variations under temperature are mostly caused by other factors.

See Table 4.1-2 for complete derails.

pH|LCO.I_O RO COIqDORATION

4-12

Space & Reentry

Syatema Division

TR-DA1522A

4.1.2 Delay Variation Produced in the Demodulation Process

As mentioned prevlo_sly, ranging delay variations in the JPL transponder

are produced principally in the demodulation process, and are caused by

variations of the reference phase relative to the carrier in the ranging

phase detector.

4.1.2.1 Description of the Phenomenon

The phenomenon is described in the sequence outlined as follows:

1. Figure A.3-4

Schematic diagram of the ranging phase detector; for reference

purposes.

2. Figure 4.1-1

Ranging channel loop functional block diagram; for reference

purposes.

3. Figure A.5-2

Transponder phase detector(s) block diagram; useful for

describing the phase relatlonshlp between reference and

carrier in the ranging phase detector.

4. _ Figure 3.2.2-4

Graph of ranging delay versus reference phase shift; this is

the chief exhibit in describing the ranging delay variation

phenomenon. The phase slope, with and without the effects

of crystal filter interaction are as follows:

(_Bd/SBref) = 0.44 deg/degnorm

(_ed/_%ref) = 0.12 deg/deg

Iso-amp

[pH,-col _HIL_Q-POmO CORI°ORAT_ON

4-13

Space _- ReentrySymtems [:)ivision

TR-DAI522A

5. Figure 3.2.2-6a and 6b

Photographs of the ranging signal in the time domain show!

the distortion of the ranging signal caused by the crystal

filter.

6. Figure 3.2.2-3

The cut-out section of the second mixer schematic diagram shows

that the crystal filter input impedance can effect the

ranging signal; the isolating pads are not adequate to

prevent the interaction effect.

7. Figures 3.2.2-1 and 2, and Table 3.2.2-1

These figures and the accompanying table show the amplitude and

phase distortion in the frequency domain, caused by the crystal

filter.

Figure 3.2.2-4 shows that a significant reduction in susceptability to

ranging delay variation can be obtained by effectively isolating the

crystal filter input impedance from the second mixer output that feeds

the ranging loop.

A limited effort was made to explain the ranging delay variation produced

in the ranging phase detector due to reference phase shift relative to the

carrier. The results of these studies are outlined as follows:

I. Appendix II.

This is a mathematical model of the demodulation of a

sinusoidal carrier which is phase modulated by a symmetrical

trapezoidal modulating waveform. The carrier frequency

relative to the frequency of the modulating signal is

infinite. The results show that for any peak phase devi-

ation or any slope, the phase of the fundamental component

of the demodulated signal is invariant. More importantly,

it shows that the phase of fundamental component of the

demodulated signal has only two discrete values, 0 and 180

degrees, relative to the modulating signal. The curve shape

4-14

I PHILCO ,l_i'"_-_->_pHILCO-_ORO COmPORATJON


TR-DA1522 A

I

,

,

PHILCO-FORO CORPORATION

shown in Figure 3.2.2-4 is not predicted in this model.

Appendix III_ll

The mathematical model described in the preceding paragraph

was augmented so as to include a complex amplitude modula-

ting waveform superimposed on the trapezoidal phase modulated

carrier. The periodicity of the complex A.M. is assumed to

be the same as the modulating signal. The results show that

the variation of the reference phase can produce the type

of curves shown in Figure 3.2.2-4, providing that there is

a large fundamental component of A.M. and that there is an

appreciable phase difference between the A.M. and P.M. wave-

forms. The A.M. component on the ranging signal due to crystal

filter interaction shown in Figure 3.2.2-6a appears to contain

a large second harmonic content, indicating that the A.M. content

may not be responsible for the large ranging variations shown

in Figure 3.2.2-4.

Appendix III.2

The fact that the 498 IOiz ranging frequency is appreciable

with respect to the 9.56MHz RF frequency was considered,

with the result that reference phase variations relative to

the ranging signal carrier phase do produce small ranging

variations. Figure A.3-3 illustrates how this can happen,

in a qualitative way. From the figures it appears that the

ultimate value of slope, for small reference variations is

• (Aed/L_ref) _ 0.05 deg/degult

Further effort on this concept could easily lead to a curve

similar to the ones shown in Figure 3.2.2-4, thus defining

the limiting ranging delay variation susceptability to reference

phase variations. The concept of ranging delay variations in

, the demodulation process illustrated in Figure A.3-3 appear

to be equally applicable to the mixing processes shown in the

4-15

Space & ReentrySystems r_ivision

TR-DAI522 A

ranging loop functional block diagram, Figure 4.1-1. Even

if true, the effect would be quite small, since the two

LO injection frequencies are 6 and 72 times higher than

the 9.56 KHz reference frequency.

This concludes the description of the ranging delay variation phenomenom

that is attributable to the demodulation process.

4.1.2.2 Causes of Reference Phase Shift

The causes of reference phase shift relative to the carrier are listed as

follows, in the order of importance as indicated by measurement data:

.

e

e

9.56 MHz IF; input to limited output:

The phase variation over the temperature range is about 76

degrees; Figure A.5-2 shows that a phase shift in the 9.56

MHz IF causes the reference phase to shift in a 1 to 1 manner.

Figure 3.1.3-14 shows that the greatest ranging delay varia-

tion, 177 nsec, occurred when the 9.56 MHz IF was subjected

to temperature variations.

IsolationAmplifier:

Figure 3.2.1-11 shows that the carrier phaseshift over

temperature is about 20 degrees. Figure A.5-2 shows that

this is equivalent to a negative reference phase shift

relative to the carrier. The measured ranging delay varia-

tion is about 64 nsec.

Frequency Divider:

The phase shift between the output to the ranging phase

detector and the APC phase detector causes the reference

phase of the ranging phase detector relative to the ranging

carrier to shift in a 1 to 1 manner; see Figure A.5-2.

4-16

PHILCO-_OAO CO mmOc_ATION


TR-DA1522 A

.

,

.

VCO Crystal:

The frequency versus temperature characteristic of the VCO

quartz crystal is responsible for causing an SPE versus

temperature variation. The result is that the ranging phase

detector reference relative to the carrier is affected on

a 1-1 basis; see Figure A.5-2. This effect is discussed in

Section 4.2.2.

The crystal filter:

The phase versus frequency slope is sufficiently steep so that

variations in S-band input frequency can cause the reference

to shift noticeably; the phase slope is approximately 0.04

deE/hertz. This effect is discussed in Section 4.2.2.

APC Phase Detector Slope:

The conversion factor _ of static phase error (SPE) to error

voltage is a function of the S/N. Since the APC loop actuat-

ing error is a fixed value under locked conditions, the phase

error must follow any change in KD, on a 1-1 basis. The net

effect then is a variation in ranging phase detector alignment,

and hence a variation in ranging delay.

This concludes the section on the causes of reference phase shift relative

to the carrier in the ranging phase detector.

4-17

["HL=Oi IBMILCO.FOA [3 CC) IN PO _ATIO N


TR-DA1522 A

4.2 TRANSPONDER PHASE RELATIONSHIPS

/'

This section concludes the analytical efforts Which were made in predict-

ing and explaining the results of the S-Band/"VCO"/ranging phase versus

temperature test measurement program.

4.2.1 General Transponder Phase Relationships

The block diagram shown in Figure A.5-1 was created in order to facilitate

the effort, This block diagram depicts the pertinent APC loop "locked"

phase relationships. It takes into account module input-to-output phase

shifts, which may be thought of as being functions of temperature, time,

or input S-Band frequency.

The equations derived in A.5-2 using this basic block diagram, predict

transient as well as steady state performance. The equations were used

primarily to predict the direction of, and in a qualitative sense the

magnitude of, the steady state value of the measured S-Band phase varia-

tions versus temperature. The APC loop mixing and frequency multiplying

processes can, and do, alter the S-Band phase deviations as compared to

the module (or module group) input'to-output values.

An example of how the equations of A.5-2 were used is as follows:

I. The steady state performance to step inputs is found by use of

the final value theorem of Laplace Transformation Theory; i.e. :

lim 8vco(t) - lim SOvco(S)

t "*_ S'*0

.where 8vco(S) = equation A.5;2.6

_t__.'. 8vc ° steady state - 110%

4-18

pN|LCO.I[OA 1:3 C(]RpOIqATION

6pace _ ReentrySystems Division

TR-DA1522 A

e Let _ be evaluated for the 9.56 MHz I.F., for example:

/!

where _ ; equation A.5.2.4

• 6 steady state ="" vco II0_

3. Finally, from equation A.5.2.7:

(SS)ou t = 120 8 = . _240)vco 2--_ 89.56

Thus it is apparent that the module input-to-output phase variation, B9.56 ,

will be modified in reaching the S-Band output by a -(240/221) factor•

Since the module phase deviation is expected to go negative with increasing

temperature, the S-Band phase will go positive with increasing temperature.

In addition, the magnitude of the shift is expected to be a small fraction

of a cycle. These observations are borne out by actual measurement (see

Figure 3.1.3-1).

This method of predicting the S-Band phase variations iS accurate to the

extent that interfacing driving point impedances do not vary. An example

of this is the apparent effect of the Frequency Divider input impedance

variation under temperature and power input varying conditions. The curve

of phase shift versus temperature and input power, Figures 3.2.1-15 and

3.2.1-16, along with the calculated multiplication factor, +(240/221),

predict only a fraction of a cycle of deviation at S-Band, compared to

the measured value of about 2.3 cycles. See Figure 3.1.3-11; note that

the phase shift curve is not monotonic, llke all of the others.

The only other example of the failure of the analysis given in A.5-2 to

explain measured S-Band phase variations is the test results of the VCO

module. ,The phase varied opposite to the expected direction, and the

magnitude was much greater than expected (13 cycles). A llst of possible

4-19

IPHL=°I _M|LCO=IIORO CO mPO_/_TION

Bpaoe J= I_a_nt:rySystemm Division

TR-DA1522A

explanations include the following, in order of expected importance:

7/i

1. The last isolation amplifier of the VCO shown in Figure

3.0-1_ which Is not taken into account in Figure A.5-1

and the derived equations, is responsible for much of

the S-Band phase deviation, since its phase deviation

is multiplied by 120 times.

e The output power of the JPL VCO module is known to

vary by about 3 db over temperature. This coupled

with the fact that the input stage of the frequency divider

is normally driven in a limiting condition, and that

the tuning is effected by the input level, leads to the

conclusion that the input impedance of the Frequency

Divider is being varied by the VCO module. The

variation in impedance varies the carrier phase angle

at that point, which then is multiplied by 120 ti_es in

reaching the S-Band output. This interface problem,

along with the VCO last isolation amplifier phase shift,

is believed mainly responsible for the large Variation

measured.

o Either or both of the two X3 multipliers and/or the

other isolation amplifiers (see Figure 3.0-1) could

be providing a positive phase shift with increased

temperature; this is not thought to be the case.

The two exceptional cases need further tests to determine the facts.

PHILCO,FORO CORPORATION

4-20

Bpace & ReentrySystemm Oivi_ion

TR-DAI522A

4.2.2 RanRinR De_laT_Variation Caused by the VCO Crystal

Temperature Characteristic

As mentioned in Section 4.1.2.2.4, the frequency versus temperature

characteristic of the VCO quartz crystal causes a variation in the

relative phase between reference and carrier in the ranging phase

detector. This in turn causes a variation in the ranging delay as a

function of temperature.

Figure 4.2.2.1 shows the expected ranging delay variation as a function

of temperature, due to this effect. The following steps show how the

curve was obtained (Note: brackets are used exclusively to indicate

functional dependence).

I. Aeref = -SSp E

2. %Sp E = VSPE/K D

.3. Vi(T)

4 • YSp E

5. VI(T)

(See Figure A.5-2)

Hypothetical internally generated bias

voltage which is equivalent to the frequency

pulling effect of temperature

= -VI(T)

= APC loop correction voltage

= Vvco[fvco(Z)_

• fVco(T) = VCO frequency versus temperature

characteristic curve; Figure 4.6-2

of "Interim Engineering Report"

4-21

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Bpace & ReentrySystems Division

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PHILI=O-FOm O CORPORATION

TR-DAI522A

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• Vvco(_vco) = Inverse of the VCO frequency versus bias

voltage curve; from data taken during this

program, but not appearing in this report.

I__ x v fVco(T)6. ASref = KD C

3. _9 d = f(A@ref) (Figure 3.2.2-4)

The curve, Figure 4.2.2.1, is hence obtained by determining the para-

meters in the given sequence, until the AOref parameter is obtained.

Then the ranging delay variation curve, Figure 3.2.2-4, is used to

compute AO d.

The curve shows an expected ranging delay variation of about 3.1 degrees,

or 17.3 n sec, as opposed to the measured variation of about 13.3 n sec.

Note that Figure 4.2.2-1 predicts a small hysteresis effect.

4-23

[ PHILCO I_PHILCO-FORO ¢OMPDRATiON

Bpace _, ReentrySystems Division

TR-DAI522 A

4.2.3 "Cog" Phase Steps

At the beginning of the S-band /"VCO"/ ranging phase versus temperature

testing program, it was noticed that the measured 'WC_' phase (i.e.,

the VCO output signal relative to the corresponding signal in the reference

transponder) would take discrete phase steps whenever the ranging channel f

was turned "on." These "Cogs" are explalned as follows:

le

e

Reference to Figure A.5-2 shows that the APC loop is

controlled at its phase detector; hence one cycle "slipped"

here should result in one "cog" of 'WCO" phase Jump.

The magnitude of one "cog" is computed by noting that the

APC converts an incremental phase change in eVCO, as defined

in Figure A.5-2, by 111 times at one input to the APC phase

detector, and by 1/2 times at the other input. Hence, for

a one cycle or 360 degree advance of the upper input relative

to the lower one

+ lll(Aeo) - [ = 360 °

• 360 ° A.. A9° = 110---_= 3.26 ° ffi1 "cog."

.

.

l..,L=ol IBHILi:O-FI=¢I CI CIO m IICIRATt(:3N

A half "cog" is theoretically possible, since the Frequency

Divider has two stable modes. Its output waveform relatlve

to the input drive signal has been observed to take either

of two phases, 180 degrees apart, due to a momentary interrup-

tion o£ the input drive.

The 'WCO Loop" shown in Figure A.5-3 is very sensitive to

VCO blas voltage transients having fast rlse times relative

to the loop filter response Clme (see Figure A.5-5). From

this Figure, a step input results In a 'WCO" phase overshoot

which Is approximately 3.2xi03 times the steady state value.

From equation A.5.3.2, the steady state value is

V i

(_evco)s. s.= (IIoD (KD) •

4-24


TR_DAI522A

The amplitude of V i that will cause the SPE to reach a

90 degree "knee" of the phase detector defines the stable

limit of V i. The incremental variation in the "VCO" phase

for this condition is:

(A@VCO)max 110% "

The final result is hence

= (3.2xi03)r vi( evco)max (ILO%>= [(llO%) (20) ]

I0_(Vi)ma x = _ I0 milllvolts peak.

3.2x103

5. The transient created in the +15 volt test power supply and

its associated leads was found to produce the "cog" phase

steps, whenever the ranging channel was turned "on," but

not "off."

6. Switching the ranging channel "on" involves only applying

D.C. power to the Isolation Amplifier module.

7. Both transponders were affected about equally, since the power

supplies were common. The measured "cogs" were predominantly

about 1.6 degrees, which is the equivalent of one-half of an

expected "cog".

8. When the transponders were connected to separate power supplies,

only the test transponder was affected. The phase Jumps were

in the order of 30 to 60 degrees, or the equivalent of many

"cogs."

9. Power supply isolating tests revealed that only the VCO module

was affected, and that isolating it eliminated the phase Jumps

altogether. Heavier transients were additionally applied to

the remainder of the transponder without any sign of "cogs."

4-25

IlIM I P.CO*PO R I_ CORPORATION

Space n Re-entrySystems Division

TR-DAI522A

The conclusions drawn from these observations are as follows:

I. Power supply transients are suspected of upsetting the VCO

via the frequency pulling varlcap. The biasing of this

varlcap should be transient-free. Further effort is required,

however, to verify that only the varicap biasing is affected.

2. The Frequency Divider can switch between the two bl-stable

modes in the APC loop "pulllng in" process.

4-26

.IpH,LcoJ DHILCO-POAO CORPDRATION


TR-DAI522 A

4.3 FREQUENCY RATIO STUDY

The results of this effort indicate a usable ratio of the transponder

transmlt-to'receive frequency as follows:

Transmit Frequency ffifd

Receive Frequency f

80

63 "

The objective of this study was to develop an analytical approach and to

use it to select an optimum value of r. It is apparent that a particular

set of constraints, when applied to the frequency relationships in a given

order will produce a value of r which is optimum in a particular sense,

The sections which follow present the analytical approach and the results

of applying one particular set of constraints in a given order.

The basic transponder configuration analyzed is presented in Figure 4.3-1,

and the significant results are presented in block diagram form in

Figure 4.3.-2.

General Discussion

The relationships presented in Section 4.3.1 comprise an independent set

of basic equations which govern the transponder frequency.relatlonships.

These relationships were used to derive the working formulas pre-

sented in Section 4.3.2, and used throughout the analysis which is

presented in Appendix VI. The analysis is presented in outline form.

The constraints which were applied in the analysis reflect the desire

to change the existing S-band transponder configuration as little as

possible, particularly the APC loop mixer signs.

4-27

PH|LCO-FORO CORPORATION Space & Re-entrySystems nivision

/ f J

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TR-DAI522 A

f

B.P.F.

(Bu)

7l

fd_ H TRANS.B. P.F. FREQ.

MULT.

<Bd) (Xd

IST

MIXER

I1STFREQ.MU LT.

t ,

IST IF

AGC 1NET.

2NDMIXER

(Xb)

2ND IF

LIM.

B

--a

fo

DET. K d

f2 t LAG• COMP.

_ [ V.C.O.

(INTEGRATOR)

Figure 4.3.-1 Basic Configuration

4.3.1 Basic Frequency Relationships*

4.3.1.I r - fd/f__

4.3.1.2 f_" afo "I" fl

• = • _" f24.3.1 3 fl bfo

4.3.1.4 f2 " Cfo

4.3.1.5 fd " dfo

*All frequencies and multiplication factors are positive quantities.

4-28

PHILCO-FO_O COR POTATIONSpace _ I::le-entrySystems Division

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4-29

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TR-DAI522A i

4.3.2 Derived Formulas

The following formulas are obtained by straightforward algebraic

means, from the basic frequency relationships given in Section 4.3.1.

4.3.2.1 fu/fo = [a • (b_c)]* i

4.3.2.2 fu/f2 = [a • (b_c)]/c

4.3.2.3 fu/fl = [a • (b_c)]/(b + c)

4.3.2.4 fl/fo = (b_c)

4.3.2.5 fl/f2 = (b:kc)/c

4.3.2.6 f2/fo = c

4.3.2.7 fd/fo = d

4.3.2.8 fd/f2 = d/c

4.3.2.9 fd/fl = d/(b_c)

4.3.2.10 fd/fu = d/[a+(b_.c)] =A r

Sign choices: .

2.

3.

4.

+c ........ fl > bfo

-c ........ fl < bfo

+(b_c) ...... fu > afo

-(b_:c) ...... f < afU 0

*Derived by Substitution of Equations 4.3.1.3 and 4.3.1.4 into

Equation 4.3.1.2.

4-30

ioH,.coi Space & IRe.entry

Systems Division

, /./

TR-DAI522A

SECTION 5

VIDEO AMPLIFIER

5.0 GENERAL

The following describes the SRS Video Amplifier which was developed as part

of the Phase II effort.

5.1 Functional Description.-

The video amplifier accepts the detected ranging modulation from the

isolation amplifier, amplifies the signal to a llmlted output level, and

provides separate outputs (isolated from one another) to each of the two

phase modulators. A block diagram of the video amplifier is shown in

Figure 5.1-1.

5.2 Speciflcation Requirements.-

The performance requirements for the SRS Video Amplifier module are

summarized in Table 5.2-1.

5.3 Problems in Mariner C Design.-

a. Both output level and pulse symmetry vary excessively

with variation in input level.

b. As a function of temperature, gain variation and pulse

asymmetry cause ranging distortion and error.

c. Rise and fall times are a function of bandwidth.e

IpH,:=ol PHILCO.FORD CORPORATION

5-1

Space _= Re-entrySystems Division

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d. Isolation between the two outputs (6 db) is marginal.

7I

e. Gain is too high both at 9.56 MHz and at 19.1 MHz.

f. Output impedance is too low and is not'controllable.

g. Insufficient bandwidth results in undesirable ranging

errors,

5.4 SRS Module Design.-

The video amplifier module has been completely redesigned to overcome the

above difficulties. The schematic diagram of the new module is shown in

Figure 5.4-1.

The incoming signal is amplified approximately 20 db by the first stage

(QI, 2N917) and then goes through a flve-pole Butterworth filter. The

3 db bandwidth of the filter is 40 Hz to 4.0 MHz. The steep attenuation

above 4 MHz assures adequate suppression of any components at the second

IF, VCO, or first IF frequencies. After the filter, the signal is

amplified approximately 20 db by the second stage (Q2, 2N917).

The third stage of amplification is a differential amplifier consisting

of a pair of 2N916 transistors CQ3 and Q4), that amplifies linearly at

input levels up to -60 dbm, then limits at all higher input levels. The

next stage is another differential amplifier (Q5 and Q6, also 2N916's) that

limits the output regardless of whether the input to this stage is linear

or has already been limited by the first differential amplifier.

The output stage for each of the two outputs is another 2N916 (Q7, QS) in

a con=non collector configuration. The gain provided at this stage brings

the signal up to the required 0 dbm output level. Separation of the out-I

p_t stages of the signals to the two exciters provides 50 db isolation

between the two outputs.

5-3

I"H'L=°iiJPHILCO.FORO CO _ PORATION

Space & Re-entrySystems [::)iris;on

TR-DA 1522 A

TABLE 5.2-1

]i

VIDEO AMPLIFIER MODULE DESIGN SPECIFICATIONS

Modulation Frequency

Impedance

Input

Output

Video Power

Input

Output

Limiting (for 3 db drop in input power)

Rise and Fall Time

Transient Response (-70 db squarewave)

Overshoot

Undershoot

Gain

9.56 MHz

19.1MHz

Current Drain

Voltage Supply

Power Output Variation

Temperature

70 Hz to 3.0 HHz

50 + 5 ohms resistive

50 + I0 ohms resistive

-70 dbm to -5 dbm

0 dbm + I db

I db max

80 nsec max

5% max

5% max

25 db max

I0 db max

50 ma max

+15 volts +3Z

+0.4, -0 db

-20°C to +75°C

IPHILCO _pPiiLCO._O RO COR pORATIQN

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5-5

Space & Re-en_rySystems [:)ivi_ion

TR-DAI522A

5.5 Test Data.-

7J!

Performance of the breadboard video amplifier module is summarized in

Table 5.5-1. Figures 5.5-1 and §.3-2 show representative oscillograph

traces from which time delay measurements were made. Figures 5.5-3 and

5.5-4 show output vs input of 9.56 and 19.1 MHz signals, respectively;

Figure 5.5-5 shows the module bandpass characteristic. Table 5.5-2 shows

the attenuation of 498 kHz harmonics.

5.6 Comparison with Mariner C Module.-

Table 5.6-1 summarizes the significant differences between the Mariner C

and the SRS Video Amplifier modules.

iPH'L=OI P_IILCO-FORO CORPORATION

5-6

Space E; Reentry

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TABLE 5.5-1

SRS VIDEO AMPLIFIER BREADBOARD TEST DATA

Current Drain (15 vdc supply)

Input Impedance

Output Impedance

Limited Gain (-70 dbm input)

Linear Gain (-85 dbm input)

Bandwidth (-85 dbm input)

Lower 3 db point

Upper 3 db point

Rise Time

-70 dbm input

-55 dbm input

Fall Time

-70 dbm input

-55 dbm input

Power Output in dbm (-55 dbm input)

43ma

48 ohms

50 ohms

70 db

85 db

40 Hz

3.4 MHz

50 nsec

50 nsec

50 nsec

50 nsec

Supply Voltage -20°C oOc +25°C +50°C +75Oc

14.5 vdc -.50 0.00 +.25 +.50 +.50

i5.0 vdc -.25 +.25 +.50 +.75 +.75

15.5 vdc 0.00 +.50 +.75 +I.00 +I.00

Limited Output Level (15 vdc supply, +25°C)

input Level Power output

-70 dbm +.50 dbm

-60 +.50

-55 +.50

-50 +.50

-40 +.50

-30 +.50

5-7

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TR-DAI522A

TABLE 5.5-1 (Continued)

SRS VIDEO AMPLIFIER BREADBOARD TEST DATA

Time Delay from Input to Output (25°C) - See Figure 5.5-1

Input Level Rise Time. Delay (nsec) Fall Time D_elax_(nsec )

-70 dbm 245 240

-60 240 235

-55 240 230-50 235 230

-40 230 230

-3O 20O 240

Time Delay from Input to Output (-55 dbm input) - See Figure 5.5-2

Temperature Rise Time Delay (nsec) Fall Time Dela_(nsec)

-20°C 235 220

O°C 240 220

+25°C 240 230

+50°c 240 230+75°C 240 250

Note : No change in time delay was observed due to supply voltage variationsof +0.5 vdc.

9.56 MHz output level (-70 dbm input)

19.1MHz output level (-70 dbm input)-52 dbm (See Figure 5.5-3)

-76 dbm (See Figure 5.5-4)

Linear Frequency Response at -85 dbm input (See Figure 5.5-5)

Frequency Output (dbm) Attenuation (db)

30 Hz -8 -640 Hz -5 -3

60 Hz -3 -I

100 Hz -2 0

50 kHz -2 0

500 kHz -2 0

1.0 l,a.Iz -2 02.0 -2 0

2.8 -3 -I

3.4 -5 -34.0 -8 -6

J PHILCO F_I_]PHILCOoFORD (_O R PQRATI ON

5-8

Space & Re-entrySystems Oivision

TR-DAI522A

(continued)

Frequenc 7 Output (dbm). Attenuation (db)

4.6 MHz -14 -12

5.0 -19 -17

5.5 -29 -27

6.0 -32 -30

7.0 -43 -41

8.0 -52 -50

9.56 -68 -66

TABLE 5.5-2

ATTENUATION OF 498 kHz HARMDNICS IN DB

498 kHz

Input

(dbm) 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0

-70 -30db -20 -50 -40 -50 -50 -50 -50 -50 -50 -50 -50 -50

-60 -30 -I0 -30 -20 -30 -20 -30 -30 -40 -50 -50 -50 -50

-50 -40 -I0 -30 -20 -30 -20 -30 -20 -30 -30 -40 -50 -50

-40 -40 -10 -40 -20 -40 -20 -40 -30 -40 -30 -40 -30 -40

Note: Attenuation is given in db below 0.0 dbm of 498 kHz output, e.g.,

-50 indicates that attenuation is at least 50 db below 0.0 dbm.

5-9

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),,4

o

(Nc'_!

l,=l

!

)

I

|

)

,!

]

!,J,,

,!

] ¸

I#

!.

IN

eQ_D

!

e_ ,4"!

-,,1

e. |

ou_

"0

o

¢M!

5=ll

PHILCO _-_] Sloace & Re-entry

Systems Division

TR-DAI522 A

-I0NO 498 KHz

SIGNAL

-20

:£mEl

Z

i'-D

I--DON

2toIn

-4(

50

---- _0

498 KHz

SIGNAL

-70 DBM

-30 DBM

-60 DBM

-40 DBM

-50 DBM

-Tq

-80

NOISE

LEVELS

-----' I L-70 -60 -50 -40

9.56 MHz INPUT IN DBM

FIGURE 5.5-3 9.56 MHz OUTPUT VS. INPUT

5-12

-30

TR-DAI522A

-I0

-2O

-3O

NO 498 KHz

SIGNAL

-40

:EmO

Z -50N

I-

lLI-::)O

N -60"r"

--

-80

I-70

I I I-60 -50

19.1 MHz INPUT IN DBM

FIGURE 5.5-4

-40 -30

19.1 MHz OUTPUT VS, INPUT

5-13

.... I ......

f i:

i

'! .... i

_I " iI ..... -T'---- ::r .... ;-,I ! i

: ': .2

-_:{,7_:uLili-_

;=] ......_, -T-I--77-

...... ; ]' i ' i. ,, : ,:1

_[iii

',_ili!l_l,_i_liiill', i ,!i

-- + i--I

:!1 i_-' ! I!

:!i![[iiit i!i i ill

:_iili_ii iiiilif!!i

::iiiii:::,! iii,_t!i_:,-i.!i!iiiii_ ;ril_}!ii

:r ;i|l_;; :::i i i:

:i_H:-!;ii:-i_i_li!!ii!ii+• " ?+i}

, .-t !! ' It ! : [it i-i=

I-C_T%F_+_1!_:!_ 14Li, ;+:-

llIil!i-i!

i:t++_1 !";++[l_]iii:i+-+I:]+' +, :+. ;

++-]-+Ii+!+:411!I!i;+

+

-.; , I , ,

iiii_

:TI iili- iit+i ¸=_ iill

___:__+,,-,o.-+ " ' I m+",4'+i,o ,:

+ I +

----r+ =T +l i;

' I_a+ ?f+li :, 13. o_

-',+_ +!I,-T-:: iii[iii i++t_iliili -t+it

: !i+I++ +i::

.-:_i!iiii _ii". . . : ; [, ..i .

_'_I!I:i !ii_::'::+++!+_il ++++I_!i!i;ii ',,!'

: Ii+:I+,'-i_i-s:_ +i+:_-u_ !!!I: ,+ ! I : t- ,'-_-_-H _ + +-+,

"+"+'" :+_+--m _i?!+,,,,-+: ++ .....li-:-l-i;rl:l-_t-I_l _ +

............. ...._+., :+.+-l+-+.,-++ _ +_-+-i.

........... I-++-+;! "? ?t't-;-t'-: ......... +..

...... t Tllltt _ ::f +"

I ' " ? .I i i:[+iP+ +i++ Ili: ++,++

.ii t; I-N.-: Li i i_i J-i+i_ i!iiLi! l+';i i.il_il+_++:,, _:'i_

; .k' : : t I '_,++,.+:I++i_I.:... ++-+I+ ,i _+J++'x++i:i-++.+, ++ :+,+,+++.+,.,++I+_ +'++!i_!+ i!+ +++_i_+_! ++.L+

+i:r :i ....... ii! I++_-¢_=',_:_-+l.I_+ i++'.+_L]l.lf_ t =_+____! ii+++[P_t+l++++_:' +_++++++I:_+-_-+!:'#+

0 t I I

I ' +I i . ] ;

!i!! .:illi:!:l : "

i,:i il _, il.!I11_i,

!!i: !+i! ; I ii:

!ii !i!_li!!ililil_' i" I '

,__L._ _'_+L ! I+ : '.+ I ; ' _

:+'_ +i ++

, i , ; ,_ , I .... i;

tttth+,t ,_,:tili4i _ii I

+-!i-i_ ii i.t+!.i+-,.:+ I+!-I!I'+!+

,i,r lii!iI_; !I j +!Ii__+t ',l_ +! .+

+i+ilJ+:++l++i+'+'- " ; _i++-t+li++i+l:ii+,._ F[+ttI,,i,_iil!i!il!_i!iiiil!;I!t_i!i+" i i ; "';-' :;:

r t I.: i ;:_-t; i+. :-! i i ':I : .-r4 t !1:-::+,

! ii

'_;iit!?+ !! !i

ii_;l_i,;ii',!!!i, iilliiil!!]!

_i:,.ili_ili:ii": "' I: _ _t+

:;:,,I!'!L/_, -_'

i:,iil_,i_!iiii' I.l ........-+,:,.-'._ ; _t: =Itt j'-;,l_t ' ,I t+ ;

:_=;+__c_| + ,+'..:'I, ; t+ ', ;_1:_-+cmlr',q !.l : ::T+

,. ,-tl.,. : , ++..i--+!

' I i

I

iii_l

:;+ _ ,

+i-![lii!,!

ii !++.++ i.+i j_,+-+-i+t+!+[!:+

-+.-1 + i-

!ili-

._;_

T;!:

i;!!,

I

• [,

i_! i i;'J _'I

i i!i_-i_::':i

I

i ; '1

! ,

::II

i;Ti

_!i-J

!:ii

I i_*-

.!!!;I. i ++

t-, i

-i-M-

lli

ii!-

:I1

i?I.

++t, + ,

+-+i-[I '

'!t-

8(] NI NOI.I.¥rIN'q.I..LY

5-14

PHILCO _IIHII.¢:O+I=O_I 0 GOUlIIICI_ATION

i!: i

; I ,

11:

+ ; !fl.l

',!I

i!l;!!

!!!!! N-

14_LL.

tit .+

! _--'T+!

i "

!!i.!

TR-DAI522 A

o

L__c;

I

• O

']i I-: : i (J)

, i _= ,,,E

' ' ' ill:;! <

I!: "r, ; _)

if+ =

ili °o:IiI u> =[;.i z "

'i ; it_l- _ E"'i! u o."

>

I

dhi

L[::D

!+-:: E

Ii,+

l!'

F:!:

! !:-i iill:

i',i4

iii: _

!: :-

, . "T"

, , + +

Ipaoi & Rm_IntryIIyitsmI r_lvliIon

TR-DA1522A

TABLE 5.6-1

l

VIDEO AMPLIFIER CHANGES FROMMARINER C

Mariner C SRS Version

le

2.

e

o

e

e

7.

8.

9.

I0.

11.

12.

Gain Variation vs Temperature

Output Level vs Input Drive

(-5 to -70 dbm)

Pulse Symmetry Variation

vs Temperature

Pulse Width Symmetry

Rise & Fall Times

(-70 dbm Input)

Output Impedance

Isolation Between Outputs

Bandwidth at -85 dbm Input

Gain at 9.56 MHz

Gain at 19.1 MHz

Symmetry Variation vs P.S.

Voltage Variations (_5 volt)

Current Drain

+2db

+ldb

50 ns

500 ns

80 ns R;90 ns F

35 ohms

6 db

1 kHz to 3.3 MHz

34 db

34 db

25 ns

21 ma

+ldb

+0.25 db

30 ns

10 ns

50 ns

50 ohms (Adjustable)

50 db

40 Hz to 3.4 MHz

18 db

-6 db

Unmeasurable

43 ma

pHt LCO.FOIR (_ COFII_O RATIO N

5-15

Space _ Re-entry

Systems Division

TR-DAI522A I

SECTION 6

CONCLUSIONS AND RECOMMENDATIONS

6.1 DISCUSSION AND REVIEW

The design study of the S-Band Turnaround Ranging Transponder was divided

into two parts, Phase I and Phase II. The Phase I effort was directed

toward general circuit and system performance improvements, and thePhase

II effort was directed towards evaluating the ranging system mainly, and

secondly towards evaluating the input-to-output S-Band phase stability

over temperature.

Due to the fact that the Phase I effort covered a broad spectrum of

topics, no attempt will be made in this section to discuss the conclusions

or recommendations resulting from that effort. A brief summary of the

design deficiencies and the proposed module and system design changes to

correct these deficiencies is presented in the Summary, Section II. For

further details, refer to the "Interim Engineering Report", WDL-TR3066.

6.1.1 Ran_inK System

Table 2.3.1-2 summarizes the ranging delay and ranging delay variation

evaluation study. In it is presented measured and expected values, for

the Mariner "C" transponder. The expected delay variation performance

can be improved greatly, as it will be shown, if the following

conditions are met:

I. Crystal filter interaction is eliminated

2. Ranging detector misalignment is held to _.20 degrees.

.iPH,.=oi iJ_M|U_O-PORO CQR_OnATIO_

Spa¢e _ Reentryiynterna [:)ivia|on

TR-DAI522A

/

DASref AT d

I (deg) (n sec)/

-20 -12.3

+20 +14.0

This data, plus the expected total group delay variation obtained from

Section 4.1.1 provide the following design goals in ranging delay

variation:

Temperature (ATd) min (ATd) max

Range (n sec) (n sec)

-AT -5.8 +20.5

+AT -1.8 +24.5

Note that now the delay variations due to group delay is now an appreciable

factor, compared to that due to misallgnment in the ranging detector.

The new maximum expected spread is then about 30.3 n sec, as compared to

measured value of 84.3. The improvement is all the moresignlficant in

view of the reduction in cancellation effects, not to mention the reduc-

tion in ranging signal distortion.

6.1.2 S-Band Phase Shift

The S-Band phase shift can be reduced to about one-half its present value

by correcting only the impedance interface problem between the VCO and the

Frequency Divider. This can be done by replacing the present VCO output

stage and the present Frequency Divider input stages with temperature

compensated, broad-band isolation stages. (Note: The preceding statements

hinge on the verification of the assumption that an impedance interface

problem exists; time and funding did not permit proper investigation of the

problem.)

6-2

iPHL=Oi pHILCO-FORO COMPORAT)ON

Bpace & ReentryISymtems O|vislon

TR-DAI522 A

It is estimated that the input-to-output S-Band phase shift can be reduced

to about five cycles. This Is equivalent to a time delay equal to 2.18 n

sec. Use of the S-Band carrier In range measurements is attractive from

the standpoint of fine range resolution, but would be complicated by "lost"

cycle counts in the mission. "Cogs" would also result in small ranging

errors, since the "VCO" phase has 221 equally probable locked states,

relative to the input S-Band signal.

6.1.3 Spectrum Analysis

Table A.4-1 lists the expected spectral amplitudes of the ranging signal

at the input and the output of the transponder. The values are based on

the mathematical model presented in Appendix IV. This analysis was a

by-product of the demooulation analysis presented in Appendix If, and was

funded on another related program. Measurements indicate that the results

are valid for the values of the parameters chosen, and are useful in

checking for unwanted variations in the input or output signals of the

transponder. Note that the test set output spectrum is non-symmetrical,

and that the transponder output spectrum indicates over-devlatlon, and

limited bandwidth as evidenced by the high value of the even sidebands.

DMIL=O-FORD COA PDRATION

6-3

6pace & ReentryBysterns Division

6.2 REcOML_NDATIONS FOR FUTURE WORK

TR-DAI522A

In order to achieve the ultimate in performance of the JPL transponder,

the following areas are recommended for future effort:

Modules

Existing Mixer Preamplifier Design lacks gain and stability.

e The Frequency Divider should be redesigned to increasestability

and give added filtering to subharmonics.

Redesign the VCO to provide isolation between frequency divider

and auxiliary oscillator outputs, and improve oscillator bias

stability.

S_stem

A transponder detail system analysis should be made to determinex

optimum gain, bandwidth, and slgnal/reference level distribution.

A review should be made to determine the optimum transponder

functional configuration.

Ranging and doppler measurements should be made on the new module

designs to verify the expected improvements. It is recon_nended

thmt modules be tested as is, at first, then updated according to

the design recommendations arising out of the Phase II effort,

and then given a final test. The tests sould be done with a JPL-

supplied transponder on an SRS module, SRS six-pack, and a com-

plete SRS transponder basis. This would allow JPL to evaluate

and accept only those changes deemed necessary.

T_e technical know-how and experience exists at Philco-SRS Division for

• efficiently investigating these areas, due to the invaluable experience

•derived from the design study progr_, JPL Contract 951290.

6-4

I"H''=OI pH|LCO.I_OR O CORDORATION

Space _ ReentrySystems I_ivision

TR-DA1522 A

APPENDIX I

PHASE SHIFT AND GROUP DELAY VS RELATIVE DETUNING

SINGLE AND TRANSITIONAL COUPLED DOUBLE TUNED FILTERS

PHILCO-FORO CQIqPORATION


TR-DAI522A

APPENDIX I

PHASE SHIFT AND GROUP DELAY VS RELATIVE DETUNING

SINGLE AND TRANSITIONAL COUPLED DOUBLE TUNED FILTERS

A.I.I Relative detunlngAw o

B B = X

Aw= w - w =A detunlng in rad/sec0

B = filter BW.3db in rad/sec

B 1 = BW.3db of 1-pole

B2 = BW 3db of 2-pole, transitionally coupled

B2 =_-2 B 1 for two identical 1-poles having B 1

and transitionally coupled

A.I.2 Phase Shift

_I = phase shift of 1-pole

_2 = phase shift of 2-pole

_)I = "tan" I(2X)

_2 = -tan- [_]

A.I-I

iDNiLCO.FORO CORPORATION

Space & Re-entrySystems nivision

From the preceeding expressions:

X

0.0

0. I

0.2

0.3

0.4

0.5

0.6

0.7

_1(. de g) " _.2,(. des.)

0.0

11.3

21.8

31.0

38.7

45.0

50.1

54.4

0.0

16.4

34.0

52.9

72.3

90.0

104.6

115.9

TR-DAI522A

This data is plotted in Figure A.I-I.

A.1.3. Group Delay*

_ d_ d_ d×dee dX dw

'rx= d× d_o= ) ( )

d_2 dX _2d_'-'Ifl'_x 2 I

*Fagot and Magne, Frequency Modulation Theory.

Pergamon Press, New York, 1961.

Note: This theory is subject to the limitation that the filter bandwidth

is large with respect to the modulation spectrum.

A.I-2

iP.,.col IIHILCO-FORO CORPORATION


_1 e4

6÷ +

I I i

i

T&-I_1522 k

<1

\0

I

,,,,4

¢=_.._

¢_,

0

0 _0

U _

I

T

A.I-3

IIH i i,,.1¢0. F 0 R 0 CORPORATION

Space & Re-enl=rySy.etem s Division

TR-DAI522A

D A.I.3.1 Fractional Change ln Group Delay Versus Relatlve_Detunlng

Let

&l _ fractional change for 1-pole

_ fractional change for 2-pole

_I _ (_i)(1+ nl)

.,2= (2 J'F"s2 )(1 + _2) .

Then, solving for _ and

I

I + 41 - I + 4X2

1 +4x2I + 16X4

4"/,2 (1-4X2),42 =+

I+I6x 4

The expressions for 41 and _ have been evaluated, and are tabulated in the

following table.

A.I-4

PHILCOIDHI_CO._O R (_ CORPORATION

Space & Re-entrySystems E:)ivi_ion

TR-DAI522A

x 4×2 t+ x4 -t00_ +1000.00 0!0000 0.0000 0.00 0.00

0.02 0.0016 2.56x10 -6 0.16 0.16

0.04 0.0064 4.10x10-5 0.64 0.63

0.06 0.0124 1.54xi0 -4 1.23 1.21

0.08 0.0264 6.97xi0 -4 2.56 2.48

0.I0 0.0400 1.60x10 -3 3.84 3.69

0.12 0.0576 3.32xi0 -3 5.41 5.10

0.14 0.0784 6.15xi0 -3 7.21 6.63

0.16 0.1024 0.0104 9.18 8.26

0.18 0.1296 0.0169 11.3 9.83

0.20 0.1600 0.0256 13.4 11.3

This data is plotted in Figure

A.I.3

A.I-I.

Croup Delay for Small Relative Detunlng, X:

The phase expressions given in Section 2. can be simplified as follows

when X is small

@I _ -2X radlans

_2 _ "2d_2"X radlans.

This results in the following simplified expressions

aI ,_-#2t

I

2j-T(1 + 1 2

ghere the _ values are in radiane, as noted above.

A.I-5

pHII._O.IIOm Q GQRPOmATION

Space & ReentrySyltems Division

A.1.4 Circuit Element Stability

A 1tU =

o

TR-DAI522A

Aw (__!_1 1 )

o J_ n_oC°

o

1

I+ + ) + L'--6-0 0 0 0

ee AL AC -2(_ )_- +_---o o o

Aw Am B_ _ X

o o

AL + 5(: 28 Aw.... (_)L C B-o o o

A.I-6

IIIH|t.CG)-PO RO (_ONPOR&TIQN

Spaca & Re_mtrySystema Division

TR-DAI522 A

To determine the temperature stability coefficient of a 1-pole or tran-

sitional 2-pole when the phase versus temperature characteristic is known.

i.

me

e

2BCalculate --

O

Aw A_Obtain--_ from the _ vs. T

graph or the simplified expressionsAw

(Note: _- = X)

Compute_ + ACo _o and divide by the temperature increment

A.1-7

ipHI LCO-FCI R O CORPORATION


TR-DAI522A

APPENDIX II

DEMODULATION OF A TPAPEZOIDAL PHASE MODULATED CARRIER

[-..,LcoI_:_IIHILCO-FORO CO III_OAATION

Space _ Re.em_.rVSystems nivislan

TR-DAI522A

7

I

APPENDIX II

DEMODULATION OF A TRAPEZOIDAL PHASE MODULATED CARRIER

A.2.1 Definitions

e

8R =

M =

2_=

f(e)=

8(t) = w t = Modulation phase variablem

reference phase relative to signal carrier

peak amplitude of phase excursion

period of slope, in assumed trapezoidal modulation

waveform (%ax = w/2)

modulation function

cos[er + f(8)] = phase detector function

eo(8)= video output waveform

Note: The R.F. carrier frequency is considered much greater than the

modulation frequency.

A.2.2 Hathematical Model Analyzed

eo(8) = K cos[e R+ f(e)]

f(e) = -M

M

-rr +e < e =-i_

=-ttt

, = - _(e - _) _- _<e<rr+e

PHILCO-_O_IO (_(_ _ PO RATIO N

A.2-I


{/ /

TR-DAI522A

-Tr

f(O)

\ i I

'V

Y'I I

A.2.2.1 Fourier Series for f(8), the Modulation Function

A t

o E A' cos n8 + B' sin n@f(O) =i- +n=l n n

f(8) ffi nS=l B'n' sin 58 ''-

' sin 8 + B_ sin 3A + B 5sin n8 = B I

B'K n : [1.(.l)n](2__M)(_)sln he.

A.2-2

pHILCO._QRD CQmPO_ATION

Space _ ;_e-en_ry

Systems Divi_;on

TR-DAI522A

A.2.2.2 Fourier.Analysis of eo(8), the video output wavegorm:

A :o

oeo(e_.. = _-. + r.n=l A cos n@ + B sin n@

n n

rr Ao = _, e (O)deK o-rr-H_

+_+_rr = (O)cos ngde_" An ,J" e o

-_,_

+r_err

Bn = t e (e) sin nedeo

A

. o_- = cos _. - 2_) cosM + 2_ L

" " +[Z+('Z)n](c°s eR) "L-M+n_ + M-n_. J " _ cos M sln n_K An

-[1'(-1)"](,i, _) ,, i' M._ " M-,_ .uK n -- . -

A.2-3

IP.,L=ol IIHOLCO-FORO CORPORATION Space & Reentry

Systems [Division

TR-DAI522A

A.2.3 Fourier Coefficients

ee

A I = B2 = A 3 = B4 • _ 0

--_B I = -2 sin 8R 2 sin M cos _-K M+_ -

A 2 = +2 cos 8R "I M+2@ + M-2_ I " cos M sin 2_

_.nB3 = -2 sin 8 { 2K R _ sin M rsin_+3@) sin(M-3@) _cos 3@ - _ L M+3_) - M-3_

- -- _ 4_}" A 4 +2 cos 8R i _[sin_+4_)+ s,in(M-4_)] _ cos M sin"g M+4_ M-4_ -K

A.2-4

IpH,L=oJ3PHILCO-ItORO CORPORATION


A.2.4 Demodulated Output (_ = &JMt)

AO

Co(t) = _--+ B I sin (WMt) + A2 cos (2&)Mt)

TR-DAI522A

+ B 3 sin (3_Mt) + A4 cos (4_Mt)

Note that @R can affect the phase of the fundamental component, B I sin _M t,

by only a change in sign; i.e., by El. The characteristic curve shape of

the ranging phase detector (Figure 3.2.2-4) is not predicted in this model.

A.2-5

IDyll LCO_FO Iq D COrPORATiON

Space & R_-__ntr ySysternm _b_on

TR-DAI522A

APPENDIX III. 1

DELAY VARIATION CAUSED BY REFERENCE PHASE VARIATION IN THE DEMODULATION

OF A RANGING SIGNAL WHICH CONTAINS COMPLEX AMPLITUDE _)DULATION

/

/

J

//

p_PLCO-_OnD COA_OmAT_ON

mpeoa & Rs_ntrySystema Dlvleton

TR-DAI522A

APPENDIX IIl.l

DELAY VARIATION CAUSED BY REFERENCE PHASE VARIATION IN THE DEMODULATION

OF A RANGING SIGNAL WHICH CONTAINS COMPLEX AMPLITUDE MODULATION

A3. I. From Appendix II, let

eofe) = K cosLeR + f(9) = demodulated video waveform

A3.2. Assume K # constant

= 1 + A(O).

That is, assume the ranging signal envelope is amplitude modulated with an

unwanted complex waveformhavlng no symmetry conditions but with the same

period as f(e), the desired phase modulation waveform.

A3.3. Let A(%) be represented by the Fourier series

ao _a

A(e) = _- +mZ=l(amcos me + b sin me)m

A3.4 Combining terms, using the Fourier series for cos[0 R + f(0)] obtained

in Appendix II.

eo(e)= [I+ a° ®Y" + [ A° -(am cos me + bm sin me) _- + nEll(An cos ne + Bn sin ne)]

i PHILCO I_JHILCO-_ORO CORPORATION

A.3-1


TR-DAI522A

B3

_--(b 2 cos 0 + a 2 sin e)

A2

_-(a 3 cos e + b3 sin e)

A4

_-(a 3 cos e - b3 sin e)

B3

_--(b4 cos e - a4 sin e)

B5

_-(b 4 cos e + a4 sin e)

A3.7 The resultant phase angle is hence

tan Aed ffi

aI b2 a_

_-(A o + A2) +_-(B I + B3) + _(A 2 + A4) + ...

ao bI a2 b3

(I+_--)(BI) +_-(A ° - A2) - _-(B 1 - B3) +_--(A 2 - A4) + • •

A3.8 For _ _ 1 (modulation approaches square wave) and ao/2 _<.i, the

expression simplifies to

alA o 2b2B 1

2 3

biAo a2B 1

B1 +"2 3

tan Aed

where

A _ 0even

B3 _ 1/3 B1

B5 etc _ 0

A •3-3

•I IF ImHILCO-FOPO CORPORATION

Space jr. Re-entrySystems Division

TR-DAI522A

a A a

eo(O ) = (I +_-_)(_-S) + (i +_) l_. (A n cos nO + Bn sln nO)

A

+ (_)E (an cos m9 + bn sin me) +. [Z(am cos m0 +bin sin mS)]

[Z(Am cos m0 + Bm sin n0)]

A3.5 The last term then becomes

O_

n_l_--l<nAncos_o,innO+bBn sin mO sin nO + a Bm n

cos mO sin nO +

b A sin mO cos nO)nn

3, r'" ""mn __ _oosl(_+_)o_ +

a B bA ]}-l, {sln[(m+n)e] sln[(,.-.,)o ]}+ n n{ _"m n . -- s,nL(m_n)el+Sln[(m-n)eJ2 .J

A3.6. Evaluating only for the fundamental term, and noting Aod d

from Appendix II.

(eo)1

a A

= (_ + _)(s I sin e) + --(_)(a I cos e + bj. sin e)

= Beven _ 0

A2

+ _-(a I cos e - bI sin e) -

A,,oh

+ _-_(aI cos e - bI sin O)

B1

+ _-(b 2 cos 0 -a 2 sin 0)

A.3-2

[PH'L=OI pMILCO.FO_O CO I_ PC) _ATION


TR-DAI522A

APPENDIX III.2

DELAY VARIATION CAUSED BY REFER]L_CE PHASE VARIATION IN TH_

DEMODULATION OF THE RANGI_ SIG_AL - AN IDEALIZED MODEL

DNgLCO-FOR D COmPOINATIO_

Bplloe & RS).en_r.y

TR-DAI522A

APPENDIX III.2

DELAY VARIATION CAUSED BY REFERENCE PHASE VARIATION IN THE

DEMODULATION OF THE RANGING SIGNAL - AN IDEALIZED MODEL

A pictorial representation of ranging delay due to reference phase variation

is illustrated in Figure A.3-3. Sketch A.3-3b shows the phase relationship

between modulated and unmodulated carrier. At t=to, the phase deviation

waveform (A.3-3a) advances the phase of the carrier +180 °. Again at

t=I/2 T498 the carrier phase is acted on and caused to shift -180 °.

Of interest is the video output of this phase modulated waveform which is

approximated by reference signal sampling of the ranging signal (A.3-3c).

If the reference signal is exactly at -90 ° with respect to the unmodulated

carrier, then it's output will be as shown in Sketch A.3-3d. However, if

the reference signal is shifted_ say • 45 ° , the video output will undergo a

delay variation as shown.

From Figure A.3-3

45 ° at 9.56MHz ffi 4__5_5 = 2.52 ° at 498 KHz.19.4

The following general relationship can be deduced:

f498 I

Phase Slope = --" i-_.4• f9.56

= 0.0515 degrees @ 498 KHz per degree @ 9.56 MHz.

This simple illustration shows qualitatively the minimum delay in the

• demodulation process due to reference signal phase shifting.

A.3-5

PMILCO-FORD CO_ORATION


TR-DAI522A

/

oD

N

IIII

I.I

IF-,IIIIIII

IIII

I

II

II

IIIIIII

I

:z;_

\

I\

o

+ I ÷

_A, _ _ _.. |

0 , 0 ,

I1=0

III

III

41t_

4_

0

0

0

I

41

tPH'LCOPHILCO-IIORO CORPORATION

A.3-6

Space 1_ R_-_ntPySystem _ -=;ivision

0.0

00

TR-DAI522A

!i

i,

A.3-?

DHILCO-_OaO COmPO_T_N8paoe Jr- _-entry

ayatem5 [_ivision

TR-DAI522A

APPENDIX IV

TRAPEZOIDAL WAVEFORMPHASE MODULATION SPECTRUM ANALYSIS, USING

THE RESULTS OF THE D_ODULATIONA}_LYSIS

PHILCO.POAO CO_BOMAT_NBpI©I & ReentrySystems Olv1_ion

TR-DAI522A

APPENDIX IV

TRAPEZOIDAL WAVEFORM PHASE MODULATION SPECTRUM ANALYSIS, USING

THE RESULTS OF THE DEMODULATION ANALYSIS

A.4.1. e(t) = cos[ w t + f(e)]O

= instantaneous R.F. voltage

A.4.2. f(8) and 8, 8R, M, and _ as previously defined

A.4.3. cart + ev S.B.'s vect: [cos f(B)] cos w tO

odd S.B.'s vect: -[sin f(e)] sin w tO

A .4.4.

A.4.5.

0

REF.

+M

Evaluation of cos f(8) and sin f(8) from demodulation analysis (Appendix II)

cos f(9)

,in f(e)

= cos [SR + f(e)]

= cos [eR +

ev. @ BR = 0°

ev. @ eR = -90°

A.4-1

lo.,.=oj 3PMILC¢)-FO_O COAPORATION

9pace £_ R_-etatrySystems D_vis_on

TR-DAI522A

Cos f(@)

sin f(s) =

Ao

__+ r A cos(n%t)_=2,4,6,"" n

Bn sln(n_Mt)n=1,3,5,-'"

where :

Ao _= I _0 T . 2@) cos M + 2@ sin M

2_]a[sin(M+n@) sin(M-n@)q 2 cos M sin n@}An = _[_L M+n_ + M-n@ -J " n

n = 2,4,6,'-"

n = 1,3.5,-"

A.4.7

Carrier =

Ao

-----cos u) CZ O

ev sldebands" (Z An cos n_MC ) cos w Co

n = 2,4,6,'"

PHI I.CO-FO RO CORPORATION

A.4-2

Space ELIRe_ntrySystems Division

TR-DA1521A

A.4.8. Odd sidbands: -(_ Bn sin n_t) s_.n w t

0

Bn

r..q__sin (Wo + n_)t

B11

z -T- sln(_o - n_)t

A.4-3

L PHILCO I_

PHILCO-FORO CORPORATION

IBpaoo s= Re.entr V8ynutomm Olvlmlon

TR-DAI522A

Ip-,-=°l_P_'q_CO- _'OqD CORPORATION

A.4-4

Space _ Re-en_rySystems Div_o_

TR-DAI522A

APPENDIX V

TRANSPONDER PHASE ANALYSIS

[PH'L=OI_"PHILCO-_Om_ CORWOAATION

8pace _= IRe_ntrySystems C)ivlgion

TR-DAI522A

7/

APPENDIX V

TRANSPONDER PHASE ANALYSIS

A block diagram, Figure A.5-1, was developed to explain the transponder

carrier phase measurements. Figure A.5.2 is a dlagram of the transponder

phase detection relationships.

Only elements known as significant contributors to phase shifts were noted

In addltlon,only transfer functions are shown. Driving pol,t-lmpeda_ce

interface effects were not taken into account although subsequent tests

indicated interface problems do contrlbute to phase shiftln so=a "instances.

A.5.1 Explanation of Symbols for All F!_ures

I j

O Amplifier

S,--mlng Junction

Amplifier of Galn "N"

Composite representation of an amplifier which contributes

a galn N and a phase shift, Oampllfler, where 6ampllfle r is

the sum of all phase shifts within the amplifier referenced

to an equivalent output value.

A.5.2 Analysis of Transponder Carrier Phase Relatignships

A.5.2.1 a 1 l+'r2S

_.(1+--_1S ) and K " KDK v

A.5.2.20vc o - KG(elV - ellI)

1- ,G{[_ Ovco+ %,]- [3evco + e._- (es_z_,

IP.,.=ol PHII.¢O-FOmO CORPORATION

A.5-1

+ lo8O,co+36e;

mpece & Reentrylystems Divimion

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O

OO

oo

A.5-2

Space & Re-entrySy.ste r_ _ I:_ivision

IP.,.col PMILCOo_ORO CORPORATION

/fL/

:1

0

o_o_

t

r_ .

0

r

<>

/ :

TR-DAI522A

I

u_

I_d

/_

ftm1.1

I

Ill

I.i04.1I,.III

I1

II10q

"0

0

I

tN

G

A.5-3

"[ Pi.-IILCO :._]Space & R_-_nt:ry

Systems Division

TR-DAI522A

A.5.2.3.

A.5.2.4.

_CO(I + 110% KG) = KG(e% - 8_ + (SS)IV - 368_ - 836 + 847.8

/

A (eS)IN .,(e= " 36 " 047.8 + 09.56)' "

Receiver, N0.1 Six-Pack

(368_ + 8_ - e_)

Recelver, No.2 Six-Pack

- 89.56)

A5.2.5. _KO8Fro= II0_KG+I

A.5.2.6.6VC 0 =

'r2

lto s + tto S2 + .r1 .... ,rl

= _(S) 4.098(S + 13.333)

(S + 13.751) (S + 439.06)

A.5.2.7.(8s)OU T = 120 8VCO + 30(84 +%M ) + 830

Receiver No. I & Transmitter six-pack

No. 2 slx-packs

NOTE:

a. _ = _(S)=ES(S) inputs, these inputs should be considered general

functions having the angular amplitudes designated

b. The APC loop is considered to be "Inlock" for all time

c. System constants are as follows:

T1 ffi276 sec

72 ffi75 Msec

K = 754 radians/volt-secV

KD = 20 volts/radian

d. @_ and Q_' are in the VCO module.

A.5-4

I_:_

IbI'41LCO-_D_D CORPORATION


A.5.2.3.

TR-DAI522A

_co(l + II0½ KG) = KG(O_ - O½ + (es)iv - 36e_ - 036 + 047.8

11

i

A.5.2.4._ A (0S)IN ,(O ,= " 36 " 047.8 + 09.56)

J

Recelver, No.l Six-Pack

(360_ + O_ - 0_) J

Receiver,No.2 Six-Pack

A5.2.5._KG

8VCO = 110%KG+I

A.5.2.6.8VC O =

%%(s+

11o KKD'2+t 110 KKDS2+ S+

= _(S) 4.098(S + 13.333)

(S + 13.751) (S + 439.06)

A.5.2.7.(es)ou T = 120 °vco + 30(04 + 8.M) + 030

Receiver No. l & Transmitter six-pack

No. 2 slx-packs

NOTE:

a. _ ffi_(S)=Z0(S) inputs, these inputs should be considered general

functions having the angular amplitudes designated

b. The APC loop is considered to be "inlock" for all time

c. System constants are as follows:

T1 = 276 Sec

_2 ffi75 Msec

K = 754 radians/volt-secV

KD = 20 volts/radian

d, @_ and @_ are in the VCO module.

A.5-4

• IIHILCO.FOIqO CORPORAT|ONI

Space & Reentry

Systems Division

TR-DAI522A

A.5.3 An Analysis of the Effect of VCO Crystal Frequency Drifts

Expressed as an Equivalent Input DC Voltage Change

Figure A.5-3 VCO Loop Block Diagram

A.5.3.1evco(S)= G(s)

vi(s) 1+H(s)c(s)

A.§.3.2 evco(S) = S2 +(II0½ KvKDT2+II_ - S'+ Ii0_ KvK D = (S+13.751)(S+439.06)

, vI / vI

NOTE: See Figure A.5-6 for typlcal graph of VCO equivalent D.C.

bias change vs temperature

A.5-5

PHILCO _ORO COAPOmATIONSpace & ReentrySystems Division

TR-DA1522A

I!

I,,I

ILl

h

!

I

?

0

0hi

v

I,-ZI11>hi

Izl

g

o

o_.1

o

Y.

III

,W

o

o

!

lu

A.5-6

Space & Re-anCrySvstem; _Jiv{siQn

TR-DAI522A

d

.... |

II

A.5-7

0

,q

_ d

_:_pace & i:le-entry

_ys._em s _ivisian

I I I I I I I

I

OD

,-_0

;::> ,.C:

4o

0_

or_ v> o

v

0

!

!

A.5-8

I

• I_

mHIL_O-FO_O =OR_ORATIONSpace & Re-entrySystems Division

TR-DAI522A

7

/

APPENDIX VI

FREQUENCY RATIO STUDY; ANALYSIS OUTLINE

[PH'L=OI pMILCCI. ImO R O CORPORATION

Space & ReentrySystems [::)lvlslon

APPENDIX VI

TR-DAI522A

FREQUENCY RATIO STUDY; ANALYSIS OUTLINE

TENTATIVE RESTRICTIONS

For purposes of analysis let

k = 1,2,3 ... (an arbitrary positive integer)

(R1)6 /1750M= f. ISSOMc 1_2200 Hc _ fd _ 2300 Mc

"2300/1850

2300/1850 =

2250/1800 =

2200/1750 =

fd/fu ¢ 2200/1750 t

46/37 = 1.2432

5/4 = =1.250044/35 1.2571

For reference only

(not part of R1)

R2. * _ f _ 50 McO

(R3)4 * ¢ fl ¢ i00 Mc

(R4) 3 8 Mc ¢ f2 _ 12 Mc

R5. * _ Bu < 2f °

R6. * < B 1 < 2f °

R7. * ¢ B2 ¢ 4.7 Kc

R8. * < B_ < *

R9. * < Bd

• Undermined limits.

PHI&,CO-POIR O CORPORATION

< 2fO

A.6-1Space & Reentry6ys.tems Division

(RI0) I fu # kfo

RII. fu _ kf2

TR-DAI522A

RI2. fu # kfl

RI3. fl # kfo

RI4. fl _ kf2

RI5. f2 _ kfo

RI6. fd = kfo

(R17) 2 fu **= fd - (k & _)fo

(R18) 7

(19)5

a = 'rrk, 2 £ k '_ 5

-A-b = k, 2_;k<

R20. c = kl/k 2, k 2 >k 1

k 1 = 1,2,3,...

k2 = 1,2,3,...

(R21)8 d " rrk, 2 _ k _ 5

NOTE: The brackets indicate only those restrictions actually used,

and the subscript indicates the order of usage.

Locates f midway between harmonics of f .u O

* Undetermined limits.

A.6-2

I PHILCOJ_j

PHILCO-FOg O CO I_PQRATION

Space & Re-en_;r'ySyatam_ Division

TR-DAI522A

A6.1. A Conditlonsal Choice of "C"

Assumptions:

RI0. f _ kfU O

RI7.1

fu = fd " (k • _)fo

Pertinent Formulas:

fd = dfo

fu/fo = a • (b_c)

Results:

fu/fo = a • (b_c) # k

Since a, b, and k are integers, c is not an integer

1fu/fo = a • (b_c) ffid - (k • _)

1A.6.1.1 C - --

2

A.6.2 Bounds on fO

Assumptions:

R4. 8 Mc

A6.1.1. c = I2

f2 _ 12 Mc

Pertinent Formulas:

4.3.1.4. f2 - C fo

A.6-3

[PH,'=OJ _MtUGO,_O_E) _ORpORATtQN

Spa=e & Re-entry6yste_s [Division

Results:

8 Mc _ I12 fo < I_ Mc?

A6.2.1 16 Mc _ f _ 24 McO

A6.3 Upper Bound on "b"

Assumptions:

R3. * _ fl S I00 Mc

R4. 8 Mc _ f2 _ 12 Mc

1A6.1.1. c _

Pertlment Formulas:

A6.2.5. ft/f2 = (b&c)/c

Results

fl max + I)bma x = c f2 min

= 1/2(-_-+ 1) = 6.7.5

A6.3.1 b = 6max

A.6.4 Lower Bound on fl

Assumptions:

R4, 8 Mc < f2 < 12 Mc

RI9. b = k, 2 < k <*

1A6.1.1 c -_

DHILCO-FOR O COPPO_ATION

A.6-4

J

TR-DAI522A

Space & Re-en_rySystems Division

Pertinent Formulas:

A6.2.5. fl/f2 = (b-_c)/c

Results:

fl mln ffif2 mln (

- (8 Mc)(_)

A6.3.1 fl mln = 24 Mc

A6.5 Bounds on "a" and "d"

Assumptions:

fl _ 1850 M:_R1 750 Mc _ fu

[.2200Mc s fd _ 2300 Mcj

R19 b = k, 2 _ k _*

A6.1.1. c - 1/2

A6.2.1. 16 Mc < f s 24 McO

A6.3.1. b = 6

Pertinent Formulas_

4.3.2.1. fu/fo

4.3.2.7. fdlfo

- a 4. (b_c)

-d

"l PHILCO _i_]IIHILCO-FO I_ O CORPORATION

A.6-5

TR-DAI522A


TR-DAI522A

Results:

fu mtn

fO maX

fU max

fo mln

fd mln f

< d _ fu max-fo max o mln

f= U mln

[a :_ (b-+-c)]mi n fO max

f_ u max

[a "- (b_c)]max fo rain

d

min

1750: 2_ = 72%

1850 5= l----T=11sg

fd rain = 220_____0= 91 2f 24 3

0 max

fd maxd =

max fo rain

= 230._._.00= 143_16

A6.5. I5

72% _ a • (b:_::) _ 115_

91 2/3 _ d _ 143_

IBounds an "d" using A6.5.1 and C =

A.6.5.2 92 _ d _ 143

Minimum bounds an "a"

A6.5.3 71 g a _ 109

A.6-6

.LPH,-=oI IIH|LCO.FORO CORDORATtON

Space & ReentrySymtems Division

A6.6 Prime Factors

TR-DAI522A

¢i?(*;

Assumptions:

R19. b ffi k, 2 a k a,

AI.1. c =- 1/2

A3.1. b = 6max

A5.2. 92 ¢ d _ 143

A5.3. 71 _ a _ 109

Results:

No.m

1

2

3

4

5

6

7

8

9

10

11

12

13

trait

71

72

73

74

75

76

77

78

79

8O

81

82

83

Prime No.'s

71

2,2,3,3

73

2,37

3,5,5

2,2,19

7,11

2,3,13

79

2,2,2,2,5

3,3,3,3

2,41

83

NO. "a"

14 84

15 85

16 86

17 87

18 88

19 89

20 90

21 91

22 92

23 93

24 94

25 95

26 96

A.6-7

Prime No. 's

2,41

5, 17

2,43

3,29

2,2,2,11

89

2,3,3,5

7,13

2,2,23

3,31

2,47

5,19

2,2,2,2,2,3

NO. "a II

27 97

28 98

29 99

30 I00

31 I01

32 102

33 103

34 104

35 105

36 106

37 107

38 108

39 109

Prime No. is

97

2,7,7

3,3,11

2,2,5,5

101

2,3,17

103

2,2,2,13

3,5,7

2,53

107

2,2,3,3,3

109

ire:pHi LCO.IIIOR D CORPORATION

Space x: Re-entrySystems Division

TR-DAI522A

No.m

1

2

3

Ilbll

2

4

Prime No._s

J

2

2,2

No.m

4

5

t I'btt

5

Prime No. 's

5

2,3

A.6-8

PHII,.CO.FO RO CORt, mORATfO N

Space & Re-entPySystems Division

No. Ifdt! Prime No 's. NO. II d If

TR-DAI522A

Prime No 's.

I

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

92

93

94

95

96

97

98

99

I00

I01

102

103

104

105

106

107

108

109

II0

III

112

113

114

115

116

117

118

119

120

:121

2,2,23

3,31

2,47

5,19

2,2,2,2,2,3

97

2,7,7

3,3,11

2,2,5,5

101

2,3,17

103

2,2,2,13

3,5,7

2,53

107

2,2,3,3,3

109

2,5,11

3,37

2,2,2,2,7

113

2,3,19

5,23

2,2,29

3,3,13

2,59

7,17

2,2,2,3,5

ii,Ii

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

5O

51

52

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

2,2,31

3,41

2,2,31

5,5,5

2,7,9

127

2,2,2,2,2,2,2

3,43

2,5,13

131

2,2,3,11

7,19

2,67

3,3,3,5

2,2,2,17

137

2,3,23

139

2,2,5,7

3,47

2,71

11,13

A.6-9

PNtLCO-_OmO CO_OO_AYlON

_pace _ Re-entrySystems _ivi_ion

TR-DAI522A

Summary 0f usable values:

Assumptions:

RI8. a - _k ,

RI9. b = k ,

R21. drink ,

A6.1. c = 112

A6.3. b = 6max

A6.5.2. 92 <

A6.5.3. 71 <

d < 143

a _ 109

2 _ k _ 5

2 _ k _; 5

• No. a b d,.,. J,. , • • ,,, ,

1

2

3

4

5

6

7

8

72(2,2,3,3_

75(3,5,5)

80(2,2,2,2,5)

81(3,3,3,3)

90(2,3,3,5)

96(2,2,2,2,2,3)

100(2,2,5,5)

108(2,2,3,3,3)

2

3

4(2,2)

5

6(2,3)

.96(2,2,2,2,2,3)

100(2,2,5,5)

108(2,2,3,3,3)

120(2,2,2,3,5)

125(5,5,5)

128(2,2,2,2,2,2,2)

135(3,3,3,5)

mMIt.CO-_O_O COAPOPATION

A.6-10

Space & ReentrySystems DivisiQn

TR-DA1522A

A6.7 Tentative Choice of fd/fd = r

t

As ions /sumpt :

A6.1. c m 1/2

A6.6. See table, summary of values on previous page

f > a£u o

fl < bfo

Pertinent Formulas:

Results:

fu/fd = d/[a "4"(b::_)] A r

(Using Mariner C sign choices)

r = dlEa + (b-c)]

A6.7.1 Table o£ a+(b-c) for usable values of a,b, and c.

No__ a a+2__ _ a_ - _ a+5 - _ a+b.-

1 72 73_ 7_ 75_ 76_ 77_

2 75 76_ 77_ 78_ 79_ 80_

3 80 81b 82_ 83_ 84_ 85_

4 81 s2_ 83_ 84_ 8_ 86_

5 90 gl_ 92½ 93_ 94_ 95_

6 96 97_ 98_ 99_. i00_ I01_

7 100 I01% I02_ 103_ I04_ I05_

8 108 109% ilO_ I11_ I12% 113%

A.6-11

PHILCOJ_._pHI_CO-_OAO CorPORATiON

Spaa:e _ Re_sntrySystems oivision

TR-DAI522A

A6.7.2 Prime Factors of 2[a+(b-c)]*

No__;. a+(b-c) 2[a+(b-c)]

1 73% 147

2 74% 149

3 75% 151

4 76% 153

5 77% 155

6 78% 157

7 79% 159

8 80% 161

9 81% 163

10 82% 165

11 83% 167

12 84% 169

13 s5% 171 "

14 86% 173

15 9{% 183

16 92% 185

17 93% 187

18 94% 189

19 95% 191

"[a + (b - c

for r =

• Prime Factor

3,7,7

3,3,17

5,31

3,53

7,23

3,5,11

13,13

3,3,19

3,61

5,37

11,17

3,3,3,7

I

)J is multiplied by 2 in anticipation of a rational fractionfd

f •U

A.6-12

phi I.CO.I_OA D CCIRPO RA'rlON

Spm=e _ ReentrySymtems [Division

TR-DAI522A

A6.7.3

.o._._ a+(b-c) 2Ca+(b'c)1

20 97_ 195

21 98_ 197

22 99_ 199

23 100_ 201

24 101_ 203

25 102_ 205

26 103_ 207

27 104_ 209

28 105_ 211

29 109_ 219

30* 110_ 221

31 111_ 223

32 112_ 225

33 113_ 227

Tentative Choices of a+(b-c)

No..._.:.. a+(b-c) __a

1 112_ 108

2 94_ 90

3 73_ 72

Present S-band value.

5 1/2

s 1/2

2 1/2

A.6-13

•Prime Factor

3,5,13

3,67

7,29

5,41

3,3,23

11,19

3,73

13,17

3,3,5,5

] PHILCO I_PHILCO-PORD CORPORATION


TR-DAI522A

Prime Factors:

/

2(112_) = 225 = 3 x 3 x 5 x 5

2(94_)

2(73_)

a

a, m

a =

ffi 189 ffi 3,3,3,7

= 147 ffi 3,7,7

= 108 = 2 x 2 x 3 x 3 x 3

90 = 2 x 3 x 3 x 5

72 = 2 x 2 x 3 x 3

A6.7.4 Resultant fd/fu = r

No. a+b-c d r

1 I12_ 135 I.2000

2 94_ 120 1.2698

3 73_ 96 1.3061

The best all-around choice is No. 2, and the final results are as follows:

fd d 120

f _b-c 9_U

2x2x2x3x5 8Oz

(2x3x3x5) + 5 - I/2 63 "

The final transponder configuration is shown in Figure 4.3-2.

[!i aPMILCO-FOq O COAPORATJON

A.6-14


TR-DAI522A

A6.7.5 Loss In Tuning Range

r =_ .5 (This value provides optimum tuning range)

u mtn ffi 5 fd mtn = (2200) = 1760 Mc

ffi4 fd ffi 4(2300) " 1840 Mcfu max max

r = 80/63:

80 80(1750) 149000 2,222_fd mln ffi_ fu min ffi63 = 6---_ =

f 63 63 _ 1,811%u max =8"6 fd max =_(2300) ffi 4

Result:

r fu mln f BW fd-- u max _ mln

5/4 1760 1840 80 2200

80/63 1750 1811% 61% 2222_

Loss of BW = 80 - 61% = ldMc

fd max

2300

2300

BWd

I00

A6.7.6 Transponder Nominal Frequencies

fd mi___n= fd mi__dd= fd ma_.._x= r

_umln _umld <max

fu mln/ max/

A.6-15

PHILCO.FORO CO I_1PO RATIO NSpace & Re-entr¥

Systems Divi_ion

TR-DAI522A

fd mid Sfd rain fd max

fU told _fu min fu max

fd mid "_/ fd rain fd max

_J_140,O00, 2300 =J5,111,1119 ,, 2260.6963

fd mid = 2260.79 Hc

2260.79fu mid =

1.2698

= 1780.43

fu mid ffi 1780.43 Mc

fd 2260.79f lit _ I

o d 120ffi18.840

f - 18.840 Mc0

1£2 " Cfo I _'(18.840) = 9.420

f2 " 9.420 Mc

fl" ('_)f2 " 5-'_ (9"420) " 84.780

fl " 84.780 Mc

A.6-16

• _r.._'_:-_

PHIt.(:o,Fr_ m O ¢;0 m _0 RATICI N


I,:,,...=,:,I!pMIt.CO-ROAD CORWOmAT#ON

1

2

3

5

7

11

13

17

19

23

29

31

37

41

43

47

53

59

61

67

71

73

79

83

89

97

101

103

107

109

REFERENCE

PRIME NUMBERS

A.6-17

113

127

131

137

139

149

1.51

157

163

167

173

179

181

191

193

197

199

211

223

227

229

233

239

241

251

257

263

269

271

277

281

TR-DAI522A

6paom & Reentrygymtemm Division

TR-DAI522A

APPENDIX VII

TEST INFORMATION FOR S-BAND/"VCO"/RANGING PHASE SHIFT VS TEMPERATURE

IDHIL=O-FOmD =ORPORATJONSpace _ I_._-mntrySystem_ O_v.L_I on

TR-DAI522A

APPEI_IXVII

TEST INFORMATION FOR S-BAND/"VCO"/RANGING PHASE SHIFT VS TEMPERATURE

The test information that follows describes the application of the ranging

equipment as utilized for the measurements made in this study. Information

on theory and procedure of operation for the MotorolaMariner S-band trans-

ponder Test Set, can be found in Motorola documents 68-26429C and 68-26430C.

A.7.1 GENERAL POINTS OF INTEREST

1. The equipment was connected as shown in the test setup block

diagramFigure 3.1-1.

2. The part of the transponder to be temperature tested was placed

in the test environment. In order to insure that room tempera-

ture variations did not cause the rest of the test transponder

to be the source of phase variations, the remaining portion of

the test transponder was placed in a reference oven.

3. After connecting the module with the rest of the transponder,

via appropriate interconnection cables, a preliminary check was

made to see that everything was operating correctly (seepreliminary

transponder checks Section A.7.3)

4. The test set was left on continuously because, at the early

pert of the program,the daily log of ranging delay showed

about • two day stabilization time after weekend shutdowns.

The transponder was only shutdown during the time a different

pert of it was placed in the test oven.

5. The Rustrak recorder charts were adjusted at the beginning of

each temperature test to correlate with the actual time of the

day. Two other recorders, used to monitor room temperature

and AC line voltage, were also adjusted to correlate with actual

A.7-1

[pN,L=ol PHII.Ct3-1cORD COIq pDImATDI3N

Space & ReentrySystemn Division

TR-DAI522A

.

.

A.7.2

time so that any variation observed on the S-band charts .-

could be corrected for posslble room temperature and

llne voltage effects. The recorder speed was one inch per

hour which permitted convenient recording of the S-band phase

changes.

Two transponders were used for the test. One was used only

to supply coherent reference signals to the "VCO" and S-band

phase detectors. To insure a phase stable reference, the

temperature and power input of the reference transponder were

maintained constant. A reference temperature of 45°C was

used to ellmlnate a need for refrigeration to maintain constant

temperature.

The DC supply power to the isolation amplifier of the reference

transponder was disconnected to turn its ranging channel off.

This made the S-band chart recordings trace smoother because

of reduced phase noise in the reference signal. The ranging

channel of the test transponder was left on continuously

because the switching action caused cog Jumps of the "VCO"

phase. (See Section 4.2.1) The phase noise on the S-band

recordings was only about a pen width in amplitude.

HIGHLIGHTS OF TEST METHOD

le

.

With the part of the test transponder to be tested placed in

the test environment and properly connected to the rest of the

test transponder in the reference oven, the test was begun

by lowering the temperature tO-10°C and allowing at

least a two hour stabilization time. The chart recorders

were not started at this time.

After stabilization, ranging phase was measured at three power

levels, -70 DBM, -90 DBM, and -110 DBM. This measurement was

done by first making a doppler phase reading with the transponder

connected to the test set. Then, the frequency converter was

A.7-2

P_UCO-FORO _OR_OmATION


TR-DAI522A

,

.

.

connected to the test set, and, by means of the test receiver

input attenuator and the ranging modulation level control,

the test receiver AGC and the ranging correlation voltage,

respectively, were made to match those recorded while the

transponder was being measured. The doppler phase reading

of the frequency converter was subtracted from the transponder

reading to give the transponder delay. Since the delay

through the frequency converter wasn't actually zero, the

absolute delay of the transponder is in slight error. However,

since the frequency converter reading was taken at each power

level at all temperature being tested, the relative ran_In_

delay change with temperature is accurate.

The S-band phase voltages were read on a digital voltmeter as

a function of input power to the test transponder. '_CO"

phase shift was also recorded at the same levels which was

from -70 DBM to -140 DBM in I0 DB steps. At the same time

all the data asked for on the data sheet (Figure A.7.1) was

recorded.

The input power was then returned to -70 DBM and the S-band

chart recorders were fixed to record. The temperature at this

time was changed to the next higher value. If the S-band

phase changed considerably with temperature, 5°C temperature

steps were made to keep the recordings legible. If little

S-band phase change was noticed with temperature, the complete

temperature change was made in one step. When whole six packs

were being temperature tested, an hour was allowed for stabili-

zation, while only 45 minutes was used in module tests.

At the end of the stabilization time, the S-band recorders were

set to stop recording, but allowed to keep running to keep the

chart correlated with the actual time of the day. The ranging

S-band and 'WCO" phase measurement were made at this time and

upon setting the charts to record, the procedure repeated until

75°C was reached.

A.7-3

IpH,L=°DI_|L(=O.WO R D (::O I_1_ORATIO N

Space & Re-entrySystems [Division

TR-DAI522A

A. 7.3 PRELL_IHARY TRANSPONDER CHECKS

I. All connectors tight (especially microdot)

2. X30 output spectrum

3. (a) Receiver in, and out, of lock

(b) Ranging on, and off

3. No signal receiver SPE < _100 my.

4. Receiver phase noise maximum peak _ 9 °, uasurad at

transponder receiver SPE test Jack; Pin = -70 dbm

5. Transmitter phase noise maximum peak > 6@. measured

at test set receiver SPE test Jack

6. Receiver AGC curve (approx. values)

Pin VAGC

(dt_) (vdc)

-70 -7.0

-90 -6.5

-110 -5.8

-152 -2.0 (threshold)

-" +1.8 (no signal)

7. False lock Is indicated if VAGC is some negative value

8. Check X36 spectrum (2.0655Gc) at transponder invut

Check TLMmodulatlon sensitivity

Check frequency for "O" volts SPE

a. "receiver phase error"

b. "transmitter phase error"

A,7-4

DNILCO.POIIIID £ONWOMAY;ON

|pill=| ; Re.entrymVmtemm [Division

J

TR-DAI522A

A.7.4 Stability of the Test Set Frequency

7 _

!The manner in whlch the stability of the test set VCO was determined

was by the observation of the transponder SPE. During the testing of

the transponder when the VCO module was in the test oven, the SPE was

noticed to change only .02 volts throughout an entire temperature test.

The manual setting of the test set VCO frequency was not changed during

any particular temperature test. Since the temperature of the trans-

ponder VCO was kept constant in a reference oven, any SPE change will be

due to test set frequency changes. The VCO frequency sensitivity is 120

Hertz per volt. This means, for a .02 volt change, there is only a 2.4

Hertz drift in the transponder VCO frequency due to the change in test

set VCO frequency change with varying room temperature.

A.7=5

tPH'L°O,I _tt.co.womo CC]_pOmATION

Space _- Reentry6ystems [:)ivisiom

TR-DAI522A

TABLE A.7-1

JPLMARINER S-BAND TRANSPONDER TEST SET SERIAL NO. 12

I. 1362 Dynamics Microvoltmeter

2. Type M TEK Plug In (Scope)

3. 45A TEK (Scope)

4. RAN. RCVR

5. 802 B HARR (Pwr. Sup)

6. TP-12 Pwr. Sup. (CCC)

7. TP-12 Pwr. Sup. (CCC)

8. BL-IO Card Files

9. B6-10 Card Piles

10. 122AR Scope

II. Test Xmit

12. Test Revr.

13. Conv. RF

14. R-100B Philbk. Pwr. Sup.

15. 480M Lambda Pwr. Sup.

16. QR. I0-I0 NJE-Pwr. Sup.

17. 802B Harrison Pwr. Sup.

32-13423

J2-19778

J2-22612

J1-862

32-19541

J2-12003

J2-11994

32-11981

J2-11985

J2-13422

J1-863

J1-839

Ji-29461

32-33325

32-33324

32-33326

J2-33327

[PH,L=O] IBl.,t I L, CO. FO R IO CORPO ¢:IATION

A.7-6


TR-DAI522A

TE_ °C POWER

SUPPLIES

RCVR -15

+15

EXCITER 15

-25

S-BAND

(Cycles) SPE

!POWER S-BAND

LEVEL O °

Volts

-70DBM

-80

-90

-i00

-ii0

-120

-140

S-BAND

Degrees

8 0 AGC I.F. ATTN

No.

MOD.

90 °

I

CORR.

VOLTS

NOTES:

I. S-band cycles are measure from the preceedlng temperature

2. (+) above at S-band cycles means advancing

Figure A.7-1 JPL Transponder Temperature Test

(Sample Data Sheet)

A.7-7

IPHILCO FO_ _ORPORATION

Bpace & Re-entrySystems Division

F'L CONTRACT 95i - NASA · presentation of the design investigation, analysis and testing...

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