NBSIR 73-236 (fi)

Field Service Test Model:

Computer-Controlled U System.

Manual for Test Unit.

R. J. Carpenter

Electronic Instrumentation

Measurement Engineering

Institute for Applied Technology

K. M. Gray

D. S. Grubb

L. J. Palombo

Measurements Automation

Information Processing Technology

Institute for Computer Sciences

and Technology

July 11, 1973

Instruction Manual

Prepared for Department of the Air Force HQ USAF (AFTAC/TAP)

Patrick A.F.B., Florida 32925

NBSIR 73-236

FIELD SERVICE TEST MODEL:

COMPUTER-CONTROLLED U SYSTEM.

MANUAL FOR TEST UNIT.

R. J. Carpenter

Electronic Instrumentation

Measurement Engineering

Institute for Applied Technology

K. M. Gray

D. S. Grubb

L. J. Palombo

Measurements Automation

Information Processing Technology

Institute for Computer Sciences

and Technology

July 11, 1973

Instruction Manual

Prepared for Department of the Air Force

HQ USAF (AFTAC/TAP)

Patrick A.F.B., Florida 32925

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

IMATIOIMAL BUREAU OF STANDARDS, Richard W. Roberts. Director

CONTENTS

Page

CONTENTS 1

1. INTRODUCTION 3

2. EQUIPMENT NEEDED WITH TEST UNIT 3

3. TEST UNIT OPERATION WITH RECEIVER ONLY 3

3.1 RF GAIN 4

3.2 PHASE 4

3.3 TRACKING RATE 5

3.4 BLANKING LEVEL 5

3.5 FREQUENCY AND CARDIOID 5

3.6 INE AND INTERRUPT 6

4. TEST UNIT OPERATION WITH ADACS INTERFACE CHASSIS AND

RECEIVER 6

4.1 RF GAIN 7 4.2 PHASE 7 4.3 TRACKING RATE 7 4.4 BLANKING LEVEL 8

4.5 FREQUENCY AND CARDIOID 8

4.6 INE AND INTERRUPT 8

5. TEST PLAN FOR RECEIVER 9

5.1 ADJUSTMENTS TO THE SlOOl CARD 9

5.2 RECEIVER IN MANUAL MODE 10

5.3 RECEIVER IN AUTOMATIC MODE 19

6. TEST PLAN FOR THE ADACS INTERFACE CHASSIS 26

6.1 ADJUSTMENTS TO THE BLANKING & INE CARD 26

6.2 ADACS TESTS 26

7. FAILURE DIAGNOSIS 38

7.1 NO AC POWER AT THE RECEIVER AND ACADS 38

7.2 INCORRECT FREQUENCY INDICATION 38

7.3 TUNING LIGHT FAILS TO GO OUT 38

7.4 NO AMPLITUDE OUTPUT TO COMPUTER 38

7.5 NO PHASE OUTPUT TO COMPUTER 39

7.6 RF GAIN UNCONTROLLED IN AUTOMATIC 39

7.7 TRACKING RATE UNCONTROLLED IN AUTOMATIC 39

7.8 BLANKING LEVEL UNCONTROLLED IN AUTOMATIC 39

7.9 PERCENT BLANKING INCORRECT 40

8. TEST UNIT CONSTRUCTION 40

8.1 CONSTRUCTION AND PARTS LIST 40

8.2 GAIN-TRACKING-PHASE CARD 41

8.3 LED DRIVER CARD 41

8.4 CHASSIS 43

1
ILLUSTRATIONS

Figure Title

1 Test Unit Cabling to Receiver

2 Test Unit with Receiver

3 Test Unit Cabling to Receiver and ADACS

4 Test Unit with Receiver and ADACS

5. . Test Unit Schematic, Sheet 1

6 Test Unit Schematic, Sheet 2

7 Test Unit Schematic, Sheet 3

8 Test Unit Schematic, Sheet 4

9 Test Unit Schematic, Sheet 5 10 Test Unit Schematic, Sheet 6

11 Tracking and Gain Chart

12 LED Driver Card

13 Gain-Tracking-Phase Card, Sheet 1

14 Gain-Tracking-Phase Card, Sheet 2 15 Blanking and INE Card (S4001) , Sheet 1

16 Blanking and INE Card (S4001) , Sheet 2 17 IC's on Gain-Tracking-Phase Card

18 MC 8311P on Gain-Tracking-Phase Card, Sheet

19 MC 8311P on Gain-Tracking-Phase Card, Sheet

20 IC's on Blanking and INE Card

21 U4 on Blanking and INE Card

22 U6 on Blanking and INE Card

23 Test Unit Front Panel - Holes

24 Test Unit Front Panel - Lettering

25 Test Unit Back Panel - Holes

26 Test Unit Back Panel - Lettering

27 Test Unit Chassis

28 Test Unit Front Panel - Components

29 Test Unit Back Panel - Components

30 Test Unit Chassis - Components

31 Test Unit Front View - Photograph

32 Test Unit Back View - Photograph

33 Test Unit Top View - Photograph

2
FIELD SERVICE TEST MODEL: COMPUTER-CONTROLLED U SYSTEM

MANUAL FOR TEST UNIT

by

R. J. Carpenter, K. M. Gray

D. S. Grubb and L. J. Palombo

1 . INTRODUCTION

The Field Service Test Model uses a computer to control the operation of from 1 to 15 EECO 881 receivers for unattended operation. Each

receiver is connected to the computer by an ADACS Interface Chassis,

which provides the necessary decoding and conversion for communications

between the receiver and the computer.

The Test Unit is a self-contained device to test the operation of

the receiver and the ADACS Interface Chassis.

When testing the receiver, the Test Unit is connected directly to

the receiver in place of the ADACS chassis. It performs the functions

of both the ADACS chassis and the computer (see figures 1 and 2).

When testing the ADACS chassis, the Test Unit is connected to the

ADACS chassis in place of the computer, where it performs the functions

of the computer (see figures 3 and 4).

It is assumed that the reader is thoroughly familiar with the

operation of the receiver and with the contents of the Manual for

Receiver and ADACS Interface Chassis.

2. EQUIPMENT NEEDED WITH TEST UNIT

Receiver and ADACS Interface Chassis being tested.

U Slmilator (generates VLF radio signal with variable amplitude

and frequency)

.

Oscilloscope to observe 3-micro second , 5-volt pulse,

3. TEST UNIT OPERATION WITH RECEIVER ONLY

This section of the manual contains a general description of the

operation of the Test Unit when it is used to test just the receiver.

The details of these tests are given in section 5 of this manual.

The receiver is tested with the Test Unit connected as shown in

figure 1. The Test Unit performs the functions of both the computer

and the ADACS Interface Chassis. For this reason, the ADACS GainTracking-Phase card and Blanking & INE card are included in the Test

3
Unit, so that they may perforin the functions that would normally be

performed by their counterparts in the ABACS chassis.

Figure 2 shows an overview of the operation of the Test Unit when

used to test just the receiver. Figures 5 through 10 show the detailed

logic of the Test Unit. The circuitry on the cards is shown in figures

12 through 16, and the integrated circuits used on the cards are shown

in figures 17 through 22. The front and back panels of the Test Unit

are shown in figures 24 and 26.

3.1 RF GAIN

The RF Gain controls in the receiver are tested by setting the

RF Gain switches on the Test Unit front panel (figure 24) to a particular value and determining what signal amplitude from the U

Simulator is necessary for the Amplitude (AGO) level from the

receiver to indicate a particular value (0 dB) on the DVM (digital

voltmeter).

The RF Gain switches (figure 8) are used both to drive the LED's

(light emitting diodes) that are above the switches and as inputs to

the Gain-Tracking-Phase card (figures 9 and 13). (The switch outputs

to connector J2 are not used in this configuration.) The Gain-Tracking-Phase card decodes the binary switch settings into signals to

activate the proper relays in the receiver (see figure 11 for a chart

of the decoding). The decoded relay signals are sent to the receiver

via connector Jl.

The Amplitude level from the receiver is connected to the DVM

by the Function switch (figure 5).

3.2 PHASE

The phase shift controls are tested by observing the Phase

Difference level from the receiver on the DVM in response to phase

shift commands by the Test Unit.

The phase is shifted in the receiver when it gets a Phase

Pulse f rom the Test Unit. To generate a Phase Pulse, the Phase

bit switch on the front panel of the Test Unit (figure 8) is set

to the on position. This will cause the LED above the switch to

go on and will enable the one shot on the Gain-Tracking-Phase card

(figure 9). Thai the operator presses the Phase Change pushbutton

(figure 5) , which causes the one shot on the LED Driver card (figure

6) to send a Phase Change Pulse to the Gain-Tracking-Phase card.

The Gain-Tracking-Phase card uses the two inputs to generate the

Phase Pulse to send via connector Jl to the receiver.

The Phase Difference level from the receiver is connected by

the Function switch (figure 5) to the DVM, permitting the operator

to see its value.

4
3.3 TRA.CKING RATE

The tracking rate controls in the receiver are tested using

the Tracking Rate switches on the Test Unit front panel to select

a particular tracking rate and observing the time required for the

receiver Phase Difference level to respond by a given amount to a phase shift.

The Tracking Rate switches (figure 8) are set to a tracking

rate. This tracking rate is indicated in the LED's above the

switches and is sent to the Gain-Tracking-Phase card (figure 9).

The Gain-Tracking-Phase card decodes the binary switch settings into

signals to activate the proper relays in the receiver (see figure 11

for a chart of the decoding). The decoded signals are sent to the

receiver via connector Jl.

The Phase Difference level from the receiver is connected by

the Function switch (figure 5) to the DVM.

3.4 BLANKING LEVEL

The blanking level controls in the receiver are tested by

setting the Blanking Level switches on the front panel of the Test

Unit to particular values and observing the resulting Percent Blanking on the DVM.

The Blanking Level switches (figure 8) are used both to drive

the LED's that are above the switches and as inputs to the Blanking

& INE card (figure 10). The Blanking & INE card converts the

binary switch settings into an analog voltage level that is sent

to the receiver via connector J8. It may also be observed on the

DVM by setting the Function switch to the Blanking Level position.

The conversion from digital-to-analog also involves the use of a non-linear network for more precise definition of small levels (see

figure 15 for the card circuitry).

The Blanking Pulses from the receiver enter the Test Unit via

J6. The Blanking Pulses are brought to a front panel connector

where they may be viewed on an oscilloscope and to the Blanking &

INE card. The Blanking & INE card contains circuitry that converts

the Blanking Pulses into an analog level, called Percent Blanking,

which is connected via the Function switch to the DVM.

3.5 FREQUENCY AND CARDIOID

The frequency bits from the receiver and the bits from the

cardioid (if used) are indicated on the front panel of the Test Unit

to determine if the computer would be getting the correct bits.

5
The frequency bits from the receiver enter the Test Unit via

connector J3 and the bits from the cardioid via connector J4. Both

go to the LED Driver card (figure 6). The outputs from the LED

Driver card go to the LED's (figure 7). See figure 12 for a schematic of the LED Driver card.

3.6 INE AND INTERRUPT

The INE (Invalid Data Equipment sensed) is used by the computer

program to indicate that the receiver or its ADACS Interface Chassis

is inoperative.

The INE signal from the receiver enters the Test Unit via

connector J3 (figure 6) and goes to the Blanking & INE card (figure

10). The circuitry on the Blanking & INE card generates an INE

output if there is either an INE input from the receiver or INE

conditions within the Test Unit, such as, an incorrect power supply

voltage level. (The Maintenance switch input to the Blanking & INE

card is grounded, so that it will not cause an INE condition.) One

of the INE output lines from the Blanking & INE card goes to a front panel connector (figure 5) and the other goes to an LED

(figure 7).

The interrupt circuitry in the ADACS Interface Chassis will

cause an interrupt to the computer if there is any change in the

status of the Maintenance switch, the Manual switch or the INE

status since the last interrupt. The Manual switch output (figure

5) is used to light the LED above the switch (figure 7), to go to

the receiver via connector Jl (figure 9), and to be monitored by

the interrupt circuit on the Blanking & INE card (figures 10 and 16)

The Maintenance switch input is grounded, so that it cannot change

status. The output of the interrupt circuit goes to the LED Driver

card (figure 6), which contains a one-shot circuit that causes the

Interrupt LED (figure 7) to flash. The output also goes to a front

panel connector (figure 5).

4. TEST UNIT OPERATION WITH ADACS INTERFACE CHASSIS AND RECEIVER

This section of the manual contains a general description of the

operation of the Test Unit when it is used to test the ADACS chassis.

The details of these tests are given in section 6 of this manual.

The receiver must be tested prior to testing the ADACS chassis, as

it is used with the ADACS chassis in the testing of the latter. The

Test Unit is connected to the ADACS chassis and the receiver as shown

in figure 3, with the Test Unit performing the functions of the computer

Figure 4 shows an overview of the operation of the Test Unit when

it is used to test the ADACS chassis. Figures 5 through 10 show the

detailed logic of the Test Unit. The circuitry on the cards is shown

6
in figures 12 through 16, and the integrated circuits used on the cards

are shovm in figures 17 through 22.

The Gain-Tracking-Phase card is not used in this test configuration,

as an identical card in the ABACS chassis is used instead. The Blanking

& INE card in the Test Unit is used only for testing the INE circuitry

in the ABACS chassis.

A.l RF GAIN

The RF Gain control circuitry in the ABACS chassis is tested

using the RF Gain switches on the front panel of the Test Unit and

determining what signal amplitude from the U Simulator is necessary

for the Amplitude (AGC) level from the receiver to indicate a particular value on the BVM.

The RF Gain switches (figure 8) are used both to drive the LEB's

that are above the switches and as outputs to connector J2 to the

ABACS chassis (figure 9). (The Gain-Tracking-Phase card is not used.)

The ABACS chassis uses its Gain-Tracking-Phase card to decode the

bits from the switches and activate the proper relays in the receiver.

It is this circuitry that is to be tested by the Test Unit.

The Amplitude level from the receiver is connected to the BVM

by the Function switch (figure 5). Figure 11 contains a chart of

the decoding.

4 . 2 PHASE

The phase shift controls in the receiver are checked with the

Test Unit connected directly to the receiver. The only ABACS circuitry involved is the one-shot circuit on the Gain-Tracking-Phase

card in the ABACS and it is checked when the tracking rate controls

are tested.

4.3 TRACKING RATE

The tracking rate controls in the ABACS chassis are tested by

using the Tracking Rate switches on the front panel of the Test

Unit and observing the time required for the receiver Phase Bifference level to respond by a given amount to a phase shift.

The Tracking Rate switches (figure 8) are set to a tracking

rate. This tracking rate is indicated in the LEB's above the

switches and is sent to the ABACS chassis via connector J2 (figure

9). The ABACS chassis uses its Gain-Tracking-Phase card to decode

the bits from the switches and activate the proper relays in the

receiver. It is this circuitry that is tested by the Test Unit.

The Phase Bifference level from the receiver is connected by

the Function switch (figure 5) to the BVM. Figure 11 contains a chart of the decoding.

7
4.4 BLANKING LEVEL

The conversion of the blanking level bits into an analog

blanking voltage level by the digital-to-analog converter on the

Blanking & INE card in the ADACS chassis is tested by setting the

Blanking Level switches (figure 8). The outputs of these switches

are used both to drive the LED's that are above the switches and as outputs to the connector J2 (figure 9). The Blanking & INE card

in the ADACS chassis converts the bits into an analog voltage which

goes to the receiver via ADACS connector J8 , A BNC tee connector

is used on J8 and a coax line is connected to the External input to

the Test Unit (figure 5). The External input is connected to the

DVM by the Function switch. The DVM indicates the voltage level

from the digital-to-analog converter, which is then compared to

the value set in the Blanking Level switches.

The conversion of the Blanking Pulses from the receiver to a Percent Blanking level by the circuitry on the Blanking & INE card

in the ADACS chassis is tested by connecting the output of that

card, ADACS connector J7 , to the External input to the Test Unit.

The External input is connected to the DVM by the Function switch

(figure 5). By varying the setting of the Blanking Level switches

to produce known Blanking Pulses conditions, the correct operation

of the conversion may be verified.

4.5 FREQUENCY AND CARDIOID

The ADACS chassis merely wires the frequency bits it receives

from the receiver directly through to the computer, so the only

testing needed is to verify the correct wiring of this connection.

The cardioid bits do not come from the ADACS chassis.

4.6 INE AND INTERRUPT

The INE circuitry in the ADACS chassis is tested by causing

INE conditions in the ADACS chassis and observing the INE indicator

on the front panel of the Test Unit. The INE signal from the ADACS

chassis comes into the Test Unit via J3 (figure 6) and goes to the

Blanking & INE card (figure 10) of the Test Unit. The output of

the card goes both to the front panel INE connector of the Test

Unit (figure 5) and to INE LED indicator (figure 7).

Interrupts from the ADACS chassis are not tested.

8
5. TEST PLAN FOR RECEIVER

The test plan consists of a number of tests on the receiver that

should be done in the sequence given as the tests build on the results

of the previous tests. In each test the settings of all equipment

controls, a test procedure, and conclusions which may be drawn from a successful result are given.

In general all numbers in the tests are decimal, the exceptions

being that of the switch settings for the Test Unit which are given

in binary. The toggle switch handle should be up for a "one". In

the case of the LED (light emitting diode) indicators, a "one" is

indicated by the light being on.

The tests are in three groups: adjustments to the SlOOl card (which

are also described in 4.6.1.2 of the Manual for Receiver and ABACS

Interface Chassis; NBSIR73-227) , tests made with the receiver in manual

mode, and tests made with the receiver in automatic (computer-controlled)

mode.

5.1 ADJUSTMENTS TO THE SlOOl CARD

There are four adjustments to be made to the SlOOl card in

the receiver. Two of these adjustments compensate for offset in

the zero output and two provide full-scale (gain) adjustment.

5.1.1 AMPLITUDE CHANNEL

Switch the receiver to manual control (using the switch

on the ADACS chassis) and switch the receiver's Servo switch

to Track. Examine the Amplitude output with the DVM of the

Test Unit. With the receiver tuned to a moderately strong

station, or to the Simulator output, adjust the receiver RF

Gain control until the front panel Signal Strength meter

reads exactly "-20 dB". Now adjust R28 on the card for zero Amplitude output as indicated on the DVM in the Test Unit.

Readjust the receiver RF Gain control until its Signal Strength

meter reads exactly "+20 dB". Now adjust R31 on the card until

the DVM reads +10.00 volts.

5.1.2 PHASE CHANNEL

With the receiver still on manual control and the

Signal Strength meter indicating mid-scale, set the Servo

switch to Negative Slew and the Tracking Rate control to 0.3

microseconds per second. Observe the Phase output of the

receiver with the DVM in the Test Unit. As the value indicated on the DVM approaches zero, adjust R38 on the card to

keep the DVM indicating zero. When the phase jumps from 0

to 360 degrees, stop turning R38. To confirm that zero degrees is represented by zero volts, switch to Positive Slew

9
and observe that just after jumping from 360 degrees to zero degrees, the DVM reads essentially zero. The full scale

adjustment R41 is made with Positive Slew as the phase

approaches 360 degrees in a like manner, keeping the DVM

indicating 7.816 volts. This completes the adjustments to

the SlOOl card.

5.2 RECEIVER IN MANUAL MODE

Before the receiver can be tested for automatic (computercontrolled) operation it is necessary to verify its operation in

manual mode. The following tests should be performed in sequence.

10
5.2.1 SUBJECT OF TEST: MANUAL OPERATION OF RECEIVER - TUNING AND

TRACKING

Configuration tested (see figure 1):

Fixed control settings ;

Receiver: RF Gain: to obtain midscale on signal level meter

Blanking : 5

Tracking Rate: 1.0

Servo: track, unless noted

Frequency: see test procedure

AC Power: see test procedure

ABACS Maintenance

Manual

Power

NOT USED

Simulator: Frequency: see test procedure

Signal Generator Control: Continuous Carrier

Square Wave

Keyed CW

Duty Factors: 0.2

Signal Phase Shift Control: Step: vis : OFF

Ramp: ys/s: OFF

Attenuation, S+N Control: Signal: 40 dB

Gaussian Noise: OFF

Impulse Noise: OFF

Test Unit: Manual: Manual

DVM: Amplitude

Switch Register: Gain:

Tracking Rate:

Blanking

Phase change:

Test procedure : Set the tuning to 10.0 kHz. Turn AC power to

ON. Observe that TUNING lamp blinks and eventually goes out.

The INE lamp on the Test Unit should be lit when the TUNING

light is lit. After the TUNING lamp goes out, the DISABLE lamp

may light. When tracking and signal strength are acceptable,

the DISABLE lamp will be out. Change the tuning at the Synthesizer and then the Receiver to 27.7 kHz. Observe that the above

pattern of lamp actions is repeated. Now switch the Servo

switch to all of its positions. The DISABLE and INE lamps

should be continuously lit in all except the TRACK and INT BAL

positions.

Conclusions :

The local oscillator synthesizer works. Portions of the INE

Circuit are operable.

11
5.2.2 SUBJECT OF TEST: MANUAL OPERATION OF RECEIVER - RF GAIN CONTROL

Configuration tested (see figure 1):

Fixed control settings ;

Receiver: RF Gain: see test procedure

Blanking : 5

Tracking Rate: 0.1

Servo : Track

Frequency: 19.9

AC Power: ON

ADACS: Maintenance

;

Manual

Power

NOT USED

Simulator;

Test Unit:

Frequency: 19.90

Signal Generator Control;

Signal Phase Shift Control:

Attenuation, S + N Control:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Step: ys : OFF

Ramp: ys/s: OFF

Signal

cedure

Gaussian Noise

Impulse Noise:

see test proOFF

OFF

Manual : Manual

DVM: Amplitude

Switch Register: Gain:

Tracking Rate

Blanking

Phase change:

DON'T CARE

Test procedure : Set the Simulator signal attenuator to 0 dB.

Find the Receiver RF Gain setting that results in a midscale

reading on the Signal Level meter. This setting should be

about 2. Set the Simulator attenuator to 50 dB and again

determine the RF GAIN setting for midscale reading. This

setting should be about 8. The DVM on the Test Unit should

read 5 + J.0 V. Set the Simulator Signal attenuator to 70 dB

and observe that the DVM reads 0 + .10 Volts, while the Signal

Level meter reads - 20 dB.

Conclusions

The RF Gain can be adjusted to accommodate the range of input

signals and the Amplitude output indicates correctly.

12
SUBJECT OF TEST: MANUAL OPERATION OF RECEIVER - BLANKING

Configuration tested (see figure 1):

Fixed control settings :

Receiver: RF Gain: to obtain mid scale on signal level meter

Blanking: see test procedure

Tracking Rate: 1.0

Servo

Frequency: 19.9

AC Power: ON

ADACS:

Simulator

Test Unit;

Maintenance

Manual

Power

NOT USED

Frequency: 19.90

Signal Generator Control:

Signal Phase Shift Control;

Attenuation, S+N Control:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

: Step: Vs : OFF

Ramp: ys/s: OFF

Signal: 50 dB

Gaussian Noise: 0 dB

Impulse Noise: OFF

Manual: Manual

DVM: Percent Blanked

Switch Register: Gain:

Tracking Rate;

Blanking

Phase change:

DON'T CARE

Test procedure : This is a test of the manual blanking level

control. These tests also verify (to some extent) proper

operation of the percent blanking-to-analog-voltage circuit

in the Test Unit. Disconnect the Blanking Pulses cable from

J6 of the Test Unit. The DVM should read 0 + .10 V. With J6

shorted the DVM should read 10 V within 0.25 V. Reconnect the

cable to J6. Vary the Blanking control and observe that for

settings below 5 the BLANKING lamp does not flash and the DVM

indicates 0 + .10 V. Rotate the Blanking control clockwise

until the BLANKING lamp appears to be continuously illuminated.

The DVM should indicate at least 3.00 V (indicating 30% blanking).

Further clockwise motion of the Blanking control should allow a DVM reading of at least 9.5 V to be obtained.

Conclusions : The internal blanking circuits operate properly

and the Percent Blanking portion of the Test Unit operates.

13
2.4 SUBJECT OF TEST: MANUAL OPERATION OF RECEIVER - TRACKING RATE

Configuration tested (see figure 1)

Fixed control settings ; Receiver: RF Gain: to obtain, midscale reading on Signal Level

meter

Blanking: 5

c- Tracking Rate: see test procedure

Servo: TRACK

Frequency: 19.9

AC Power : ON

ABACS:

Simulator

Maintenance

Manual

Power

NOT USED

Frequency: 19.90

Signal Generator Control

Signal Phase Shift Control:

Attenuation, S+N Control:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor:

Step: ys : Ramp: ps/s:

Signal: 50 dB

Gaussian Noise

Impulse Noise:

0.2

see test

procedure

OFF

OFF

Test Unit Manual : Manual

DVM: Phase

Switch Register: Gain:

Tracking Rate:

Blanking

Phase Change:

DON'T CARE

Test procedure ; The tracking rate will be roughly checked by

causing a phase step in the signal and observing the response

time of the phase output of the receiver, using the DVM as an

indicator. Place the Tracking Rate Switch at 5 ys/s. Place

the RAMP switch on the Simulator in the ADV or RET position

and press the step push button until the DVM reads about 4 V,

Write down the voltage step corresponding to a 10 ys phase step.

For each of the following settings of the Receiver Tracking Rate

control observe that the DVM takes the listed time to change by

62% of the voltage step measured above.

Tracking Rate setting ps/s 5 1 0.5 0.1

Time for 62% of step s 2 10 20 100

Allow the reading to fully settle between each test. In order

to keep on scale, the Simulator RAMP switch should be reserved

after each test.

Conclusions : Achievement of the above results indicates that

the Receiver tracking rate circuits are functioning satisfactorily.

14
5.2.5 SUBJECT OF TEST: CORRECT FULL-SCALE RANGE. ON PHASE OUTPUT:

50 ys SHIFT

Configuration tested (see figure 1):

Fixed control settings ; Receiver: RG Gain: to obtain midscale reading on Signal Level

meter

Blanking : 5

Tracking Rate: 0.1

Servo : see test procedure

Frequency: 19.9

AC Power: ON

ABACS:

Simulator

Maintenance

;

Manual

Power

NOT USED

Frequency: 19,9

Signal Generator Control

Test Unit:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Signal Phase Shift Control: Step: us : OFF

Ramp: ys/s: OFF

Attenuation, S+N Control: Signal: 50 dB

Gaussian Noise: OFF

Impulse Noise: OFF

Manual : Manual

DVM: Phase

Switch Register: Gain:

Tracking Rate:

Blanking

Phase change:

j DON'T CARE

see test procedure

Test procedure : The analog output of the receiver that is used

to indicate phase will be examined to determine if its amplifier

gain and zero are set correctly. The test method involves use of

the 50 ys Phase Change system, which results in exactly a halfscale change in the phase output each time the phase is changed

by 50 ys. First the operation of the phase changer must be

checked. Set the SERVO switch to TRACK. Set the Phase switch on

the Test Unit to 0, then push the Phase Change button. The DVM

reading should not appreciably change. Now set the Phase switch

to 1 and press the button again. The DVM reading should change

exactly 3.908 V each time the button is pressed, alternately

positively and negatively. Any error in this value indicates

that the phase amplifier on the SlOOl card in the receiver is set

for the incorrect gain. An error of 0.05 V is acceptable.

To observe the zero adjustment of the Phase channel, switch the

Servo control to the NEG SLEW position and observe the DVM

readings. They will progressively decrease and then jump to

about 7.816 V and slowly decrease again. The value just before

15
5.2.5 (Cont'd)

the jump to full-scale is the "zero". This should be within

0.05 V of zero.

Conclusions ; The phase output signal is correct and the 50 y.s phase shift system works.

16
5.2.6 SUBJECT OF TEST: MANUAL OPERATION OF RECEIVER - REMOTE FREQUENCY

INDICATION

Configuration tested (see figure 1):

Fixed control settings ;

Receiver: RF Gain: 5

Blanking : 5

Tracking Rate: 1»0

Servo : TRACK

Frequency: see test procedure

AC Power: ON

ABACS: Maintenance

Manual

Power

NOT USED

Simulator: Frequency:

Signal Generator Control: Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Signal Phase Shift Control: Step: ys : OFF

Ramp: ys/s: OFF

Attenuation, S+N Control: Signal:

Gaussian Noise: OFF

Impulse Noise: OFF

Test Unit: Manual: Manual

DVM: DON'T CARE

Switch Register: Gain:

Tracking Rate:

^ Blanking

Phase change:

Test procedure : Proper operation of the remote frequency indicating system will be determined by setting each frequency dial

to the useful values and observing the remote indication on the

lamps of the Test Box. The frequency is Indicated in nine's

complement, binary coded decimal; i.e.

dial lamps

0 1001

1 1000

2 0111

3 0110

etc

8 0001

9 0000

17
5.2.6 (Cont'd)

The frequency should always lie in the range of 10.0 and 29.9

kHz. Set the tenths dial successively to all its values and

observe that the correct lamps are lit. Do the same for the

units dial. Set the tens dial to 1, and 2 and observe that

the Test Unit lamps indicate only the last two bits of the

; correct number.

Conclusions : The remote frequency indicating system is

operating correctly.

18
5.3 RECEIVER IN AUTOMATIC MODE

The following tests verify that the receiver works correctly

when under automatic (computer-controlled) operation.

19
5.3.1 SUBJECT OF TEST: REMOTE OPERATION OF RECEIVER - GAIN CONTROL

Configuration tested (see figure 1)

Fixed control settings;

Receiver: RF Gain: any, is also varied during test

Blanking : any

Tracking Rate: any

Servo : any

Frequency: 19.9

AC Power: ON

ABACS: Maintenance

Manual

Power

NOT USED

Simulator: Frequency: 19.90

Signal Generator Control

Signal Phase Shift Control:

Attenuation, S+N Control:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Step: ys : OFF

Ramp: ys/s: OFF

Signal: 50 dB

Gaussian Noise: OFF

Impulse Noise: OFF

Test Unit: Manual: Automatic

DVM: amplitude

Switch Register: Gain: see test procedure

Tracking Rate: 0000

Blanking: 110000

Phase change: 0

Test procedure : This test determines correct remote control of

RF gain. The procedure is to set the Receiver gain by remote

control to each of the possible values and determine the Simulator output amplitude setting that results in a 0 dB reading

on the Signal Level meter. There should be smooth relationship

between gain and required signal. Any steps differing by more

than 2 dB from the smooth curve indicate malfunction. Lowest

gain occurs with a switch setting of 00000. Highest gain occurs with a switch setting of 11000. Any higher switch settings

results in uncontrolled higher gain and improper operation. To

make the measurement, set the Test Unit gain switches to 01000,

and record the Simulator output setting SI required to obtain

a 0 dB reading on the Receiver Signal Level meter. Now set

the Test Unit gain switches to 11000, and again record the

Simulator output setting required to obtain a 0 dB reading on

the Receiver Signal Level meter. These Simulator levels should

be about 0 and 50 dB respectively. Rotate the Receiver RF Gain

20
(Cont'd)

control and observe that there is no effect on the signal level

meter reading. Now calculate the ratio (S2-S1)/16. This gives

the average Receiver gain step size in dB. Verify that all

gain steps are within 2 dB of being correct.

Conclusions : The remote control of the Receiver gain operates

correctly.

21
5.3.2 SUBJECT OF TEST: REMOTE OPERATION OF BLANKING LEVEL CONTROL

Configuration tested (see figure 1)

Fixed control settings ;

Receiver

;

ABACS;

Simulator

RF Gain: any

Blanking: (changed during test)

Tracking Rate: any

Servo : any

Frequency: 19.9

AC Power: ON

Maintenance

Manual

Power

NOT USED

Frequency: 19.90

Signal Generator Control: Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Signal Phase Shift Control: Step: ys : OFF

Ramp: ys/s: OFF

Attenuation, S+N Control: Signal: 50 dB

Gaussian Noise: 10 dB

Impulse Noise: OFF

Test Unit: Manual: Automatic

DVM: see test procedure

Switch Register: Gain: to obtain midscale reading

on Signal Level

Tracking Rate: 0000

Blanking: see test procedure

Phase change: 0

Test procedure : This is a test of the remote blanking level

control. These tests verify (to some extent) proper operation

of the Blanking Control and percent-blanked-to-analog-voltage

portions of the Test Unit. Set the DVM to Blanking Voltage.

Set the Blanking control switches to 000000. The DVM should

read 0 V within 50 mV. Set the switches to 010000, the DVM

should read -.50V within 0.05V. Set the switches to 1000000,

the DVM should read -2V within 0.2V. Set the switches to

110000, the DVM should be -6V within 0.6V. Set the switches

to mill, the DVM should read greater than -lOV. Now switch

the DVM to the Percent Blanked position for the rest of this

test. Set the Blanking switches of the Test Box until the DVM

reads l.OOV (10% blanking). The switches should be 011000

within 000010. Now change these switches to obtain a DVM

reading or 3.0V. The switch combination should be 010011 within

22
5.3.2 (Cont'd)

000010. Rotate the Receiver Blanking control over its range and

observe that there is no change in the DVM reading.

Conclusions : Remote control of blanking level is possible and

the Blanking Control portion of the Test Unit also operates.

23
5.3.3 SUBJECT OF TEST: REMOTE CONTROL OF RECEIVER - TRACKING RATE

Configuration tested (see figure 1)

Fixed control settings ;

Receiver

RF Gain: any

Blanking : any

Tracking Rate: any

Servo : any

Frequency: 19.9

AC Power: ON

ABACS: Maintenance

Manual

Power

NOT USED

Simulator: Frequency: 19.90

Signal Generator Control: Continuous Carrier

Signal Phase Shift Control: Step: ys : see test

Ramp: ys/s: procedure

Attenuation, S+N Control: Signal: 50 dB

Gaussian Noise: OFF

Impulse Noise: OFF

Test procedure : The tracking rate will be roughly checked by

causing a phase step in the signal and observing the response

time of the phase output of the receiver using the DVM as an

indicator. Place the Test Unit Tracking Rate switches in the

fastest rate 1001 (7 ys/s) . Place the RAMP switch of the

Simulator in the ADV or RET position and press the step push

button until the DVM reads about 4 V. For each of the following

settings of the Test Box Tracking Rate switches, observe that

the DVM takes approximately the listed time to change by 62%

of the value measured for a 10 ys step in the test "Manual

operation of receiver - tracking rate".

Tracking Rate switches 1000 0101 0100 0000

Time for 62% of step 2 10 20 160 seconds

Allowing the reading to settle between each test. In order to

keep on scale, the Simulator RAMP switch should be reversed

after each test.

Conclusions : Correct operation of the tracking rate remote

control and the associated decoder in the Test Unit is

determined by this test.

Square Wave

Keyed CW

Duty Factor: 0.2

24
SUBJECT OF TEST: INE OPERATION

Configuration tested (see figure 1)

Fixed control settings ;

Receiver: RF Gain: any

Blanking : any

Tracking Rate : any

Servo: see test procedure

Frequency: see test procedure

AC Power: ON, is turned off during test

ABACS:

Simulator

Test Unit;

Maintenance:

Manual

Power

NOT USED

Frequency: 19.90

Signal Generator Control

Signal Phase Shift Control

Attenuation, S+N Control:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

: Step: ys : OFF

Ramp: ys/s: OFF

Signal: 50 dB

Gaussian Noise: OFF

Impulse Noise: OFF

Manual : Automat ic

DVM : any

Switch Register Gain: to obtain midscale on Signal Level meter

Tracking Rate: 0000

Blanking : 110000

Phase change: 0

Test procedure : This test is to determine proper operation of

the INE circuits in the modified receiver when in the Automatic

mode. The first portion of the test determines that the SERVO

switch has no effect in Automatic. Observe the INE lamp while

rotating the Servo switch. It should not light in any position.

Reset the Simulator to 20.1 kHz and wait for the Signal Level

meter to go below -20 dB. The INE should not light. Reset the

Simulator to 19.9 kHz. Turn Receiver AC POWER switch off. Note

that the INE lamp remains on. After waiting a few seconds, turn

the AC POWER back on. The INE will blink until the TUNING lamp on the Receiver goes out.

Conclusions : The Receiver portion of the INE circuit operates.

25
6. TEST PLAN FOR THE ABACS INTERFACE CHASSIS

Testing of the ABACS chassis includes both the adjustment of zero and full scale settings of a circuit on the Blanking & INE card, and a series of tests on the unit.

The receiver must be tested prior to testing the ABACS chassis,

as it is used with the ABACS chassis in the testing of the latter.

6.1 ABJUSTMENTS TO THE BLANKING & INE CARB

The circuit on this card for converting the Blanking Pulses

into an analog Percent Blanking voltage has both a zero setting

and a full scale setting. The zero setting uses a fixed resistor

and the full scale setting uses an adjustable pot.

Remove the cable to J6, connect a coax cable from J7 to the

External input connector on the front panel of the Test Unit, and

set the Function switch of the Test Unit to External. The voltage

indicated on the BVM (digital voltmeter) in the Test Unit should

be zero, plus or minus 50 millivolts. If not, a new value for R17

is needed. Use a higher value of resistance if the voltage is

negative.

With the cable to J6 still disconnected, connect a shorting

cap to J6. The BVM voltage should be adjusted with R18A on the

card to give a reading of +10.00 volts.

6.2 ABACS TESTS

The test plan consists of a number of tests using the receiver

and the ABACS chassis connected as shown in figure 3. The tests

should be done in the sequence given. In each test the settings

of all equipment controls, a test procedure, and conclusions which

may be drawn from a successful result are given.

In general all numbers are decimal, the exception being that

of the switch settings for the Test Unit which are given in binary.

- The toggle switch handle should be up for a "one".

The tests are performed using the Test Unit to simulate

computer commands. In almost all cases the actions may be commanded

: from the operator console when using the receiver /ABACS chassis

J under computer control. All tests made in this section of the

manual should be repeated using the computer to establish the

conditions and observe the results.

26
6.2.1 SUBJECT OF TEST: OPERATION OF PERCENT BLANKING PORTION OF ADACS

Configuration tested (see figure 3)

Fixed control settings :

Receiver: RF Gain:

Blanking

Tracking Rate:) DON'T CARE

Servo

Frequency

AC Power: ON

ADACS:

Simulator

Test Unit;

Maintenance: either

Manual: either

Power : ON

Frequency:

Signal Generator Control;

Signal Phase Shift Control:

Attenuation, S+N Control:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Step: ys : OFF

Ramp: ps/s: OFF

Signal

Gaussian Noise: OFF

Impulse Noise: OFF

Manual : either

DVM: PERCENT BLANKING

Switch Register: Gain:

Tracking Rate;

Blanking

Phase change:

DON'T CARE

Test procedure : This test determines the 0% and 100% blanking

readings of the Percent Blanking portion of the ADACS. The test

is conducted with the normal wire to J6 of the ADACS disconnected.

With this wire disconnected , the DVM should read 0 V within 100

mV. With the center terminal of J6 shorted to its shell, the DVM

should read 10.00 V within .25 V. Percent blanking is directly

read by moving the DVM decimal place one place to the right. A

reading of 1.00 V means 10.0% blanking.

Conclusions : The percent blanking circuit in the ADACS is

operating properly.

27
2.2 SUBJECT OF TEST: OPERATION OF RECEIVER THROUGH ABACS - FREQUENCY

INDICATION

Configuration tested (see figure 3)

Fixed control settings ;

Receiver: RF Gain: any

Blanking : any

Tracking Rate: any

Servo: TRACK

Frequency: see test procedure

AC Power: ON

ABACS; Maintenance: NORMAL

Manual : MANUAL

Power : ON

SimulatorFrequency:

Signal Generator Control; Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Step: ys : OFF

Ramp: ys/s: OFF

Attenuation, S+N Control: Signal:

Gaussian Noise: OFF

Impulse Noise: OFF

Signal Phase Shift Control:

Test Unit: Manual : either

DVM: any

Switch Register: Gain:

Tracking Rate;

Blanking

Phase change:

DON'T CARE

Test procedure ; Proper operation of the remote frequency

indicating system will be determined by setting each frequency

dial to the useful values and observing the remote indication

on the lamps of the Test Box. The frequency is indicated in

nine's complement, binary coded decimal; i.e.

dial lamps

0 1001

1 1000

2 0111

3 0110

etc

.

8 0001

9 0000

28
6.2.2 (Cont'd)

The frequency should always lie in the range of 10.0 and 29.9

kHz. Set the tenths dial successively to all its values and

observe that the correct lamps are lit. Do the same for the

units dial. Set the tens dial to 1 and 2 and observe that the

Test Unit lamps indicate only the last two bits of the correct

number

Conclusions ; The remote frequency indicating system is operating

correctly.

29
6.2.3 SUBJECT OF TEST: REMOTE CONTROL OF RECEIVER ADACS-GAIN CONTROL

Configuration tested (see figure 3):

Fixed control settings :

Receiver: RF Gain: any

Blanking : any

Tracking Rate: any

S Servo: any

Frequency: 19.9

AC Power: ON

ABACS: Maintenance: NORMAL

Manual : AUTOMATIC

Power : ON

Simulator: Frequency: 19.90

Signal Generator Control:

Signal Phase Shift Control

Attenuation, S+N Control:

Test Unit: Manual: either

DVM: Amplitude

Switch Register;

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

: Step: ys : OFF

Ramp: ys/s: OFF

Signal:

Gaussian Noise: OFF

Impulse Noise: OFF

Gain: see test procedure

Tracking Rate: 0000

Blanking : 110000

Phase change: 0

Test procedure : This test determines correct remote control

of RF gain through the ADACS. A previous test has determined

that the gain control card in the Receiver operates. This

test is to assure that the decoder and wiring in ADACS are

correct. The procedure is to set the Receiver gain by remote

control to each of the possible values and determine the

Simulator output amplitude required to obtain a 0 dB reading on the Receiver Signal Level meter. There should be a smooth

relationship between gain and required signal. Any steps

differing from the smooth curve by more than 2 dB indicate a malfunction. A gain-per-step value for each receiver is determined in the test "Remote operator of receiver - gain control".

Using this value, go through all gain steps and determine the

associated Simulator output required. Verify that all steps are within the 2 dB tolerance.

30
6.2.3 (Cont'd)

Conclusions ; The remote control of Receiver gain using the

decoder in the ADACS unit operates correctly.

31
6.2.4 SUBJECT OF TEST: OPERATION OF RECEIVER THROUGH ABACS - BLANKING

LEVEL CONTROL

Configuration tested (see figure 3):

Fixed control settings ;

Receiver: RF Gain: any

Blanking : any

Tracking Rate: any

Servo: any

Frequency: 19.9

AC Power: ON

ABAC S : Ma intenance : NORMAL

Manual: AUTOMATIC

Power: ON

Simulator: Frequency: 19.90

Signal Generator Control:

Signal Phase Shift Control:

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Step: vs : OFF

Ramp: ys/s: OFF

Attenuation, S+N Control: Signal:

' Gaussian Noise: OFF

Impulse Noise: OFF

Test Unit: Manual: either

DVM: EXTERNAL, changed during test

Switch Register: Gain: to obtain midscale reading

on Signal Level

Tracking Rate: 0000

Blanking: see test procedure

Phase change: 0

Test procedure : This is a test of remote control of blanking

using the Blanking Control card in ABACS. A previous test has

determined that blanking level of the receiver can be remotely

controlled. The first step in this test is to determine the

correct operation of the digital-to-analog converter in ABACS

which produces the Blanking Control Voltage. The external

voltage input for the BVM on the Test Unit is connected by a tee to the Blanking Control Voltage output on the ABACS. Set

the blanking switches and read the BVM voltages. Compare with

this table.

32
6.2.4 (Cont'd)

Switches Lowest Voltage Highest Voltage

000000

010000

100000

110000

mill no limit

-0.05

-5.5

-2.2

-6.6

0.05

-4.5

-1.8

-5.4

-10.0

Connect the cable from the External input of the Test Unit to

the Percent Blanking output of the ABACS, Adjust the Blanking

Control Switches so that the Blanking light never lights. The

DVM should read 0.0 V within 100 mV. Now change the Blanking

control switches until the DVM reads 2.00 V as closely as possible. This is the voltage produced by the ABACS. A

similar circuit is contained in the Test Unit. Its voltage

should be read by switching the BVM to the PERCENT BLANKING

position. The two values should agree within 100 mV.

Conclusions ; The Blanking circuitry of the ABACS operates.

33
.2.5 SUBJECT OF TEST: OPERATION OF RECEIVER THROUGH ADACS - TRACKING

RATE

Configuration tested (see figure 3):

Fixed control settings :

Receiver: RF Gain: any

Blanking : any

, Tracking Rate: any

_ . Servo : any

Frequency: 19.9

AC Power : ON

ADACS: Maintenance: NORMAL

Manual : AUTOMATIC

Power : ON

Simulator: Frequency: 19.9

Signal Generator Control: Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

Step: vs : OFF

Ramp: ys/s: OFF

Attenuation, S+N Control: Signal:

Gaussian Noise: OFF

Impulse Noise: OFF

Signal Phase Shift Control:

Test Unit: Manual : either

DVM: PHASE

Switch Register: Gain: to obtain midscale reading

of Signal Level

Tracking Rate: see test procedure

Blanking : 110000

Phase change: 0

Test procedure : The tracking rate will be roughly checked by

causing a phase step in the signal and observing the response

time of the phase output of the receiver using the DVM as an

indicator. Place the Test Unit Tracking Rate switches in the

fastest rate 1001 (7 Us/s). Place the RAMP switch of the Simulator in the ADV or RET position and press the step push button

until the DVM reads about 4 V. For each of the following settings

of the Test Unit Tracking Rate switches, observe that the DVM

takes approximately the listed time to change by 62% of the

value measured for a 10 ys step in the test "Manual operation of

receiver - tracking rate".

Tracking Rate switches 1000 0101 0100 0000

Time for 62% of step 2 10 20 100 seconds

34
6.2.5 (Cont'd)

Allow the reading to settle between each test. In order to

keep on scale, the Simulator RAMP switch should be reversed

after each test.

Conclusions : Correct operation of the tracking rate remote

control and the associated decoder in the ABACS chassis is

determined by this test.

35
6.2.6 SUBJECT OF TEST: INE OPERATION OF RECEIVER AND ADACS

Configuration tested (see figure 3):

Fixed control settings ;

Receiver: RF Gain: 5

Blanking : 5

Tracking Rate: 0.1

Servo: TRACK, varied during test

Frequency: 19.9, will be varied during test

AC Power: ON, varied during test

ADACS:

Simulator

;

Test Unit;

Maintenance: NORMAL, changed during test

Manual: AUTOMATIC, changed during test

Power: ON, changed during test

Frequency: 19.90

Signal Generator Control

Signal Phase Shift Control

Attenuation, S+N Control:

Manual : either

DVM: any

Switch Register

Continuous Carrier

Square Wave

Keyed CW

Duty Factor: 0.2

: Step: ys : OFF

Ramp: ys/s: OFF

Signal

Gaussian Noise: OFF

Impulse Noise: OFF

Gain: to obtain midscale on Signal

Level meter

Tracking Rate: 0000

Blanking: 110000

Phase change: 0

Test procedure : Operation of the INE system will be verified.

The Receiver parts of the system have been tested before. The

Interrupt lamp on the Test Unit is not connected to the Interrupt output on the ADACS. The INE lamp in the Test Box will

indicate INE conditions in the ADACS, but the Interrupt lamp

is meaningless. Observe the interrupt pulse with an oscilloscope

connected to either Interrupt BNC connector on the rear of ADACS.

Let the system stabilize with the INE lamp extinguished. Suddenly change the Receiver tuning to 29.9 kHz. The TUNING lamp of

the receiver will blink resulting in a blink of the INE lamp

and an interrupt. When the tuning is reset to 19.9 the same sequence of events should occur. Turn the Receiver AC POWER

switch off. There should be an interrupt and the INE lamp

should remain lit. When the AC POWER is turned on there should

36
6.2.6 (Cont'd)

be another interrupt and the INE should eventually go out. Turn

the Maintenance switch to MAINTENANCE; there should be an interrupt and the INE lamp should remain lit. After a few seconds

return this switch to NORMAL; there should be another interrupt

and the INE lamp should extinguish. Turn the INE Manual switch

to MANUAL; there should be an interrupt but the INE lamp should

NOT light. Return this switch to AUTOMATIC; there should be

another interrupt but no INE light. Turn the ADACS OFF and

observe that there is an interrupt.

Conclusions ; The INE system has been tested when this and the

previous tests are complete.

37
7. FAILURE DIAGNOSIS

The following service advice may be of assistance in the diagnosis

of system failures. The use of the Test Unit in the diagnosis is

assumed.

7.1 NO AC POWER AT THE RECEIVER AND ADACS

a) The computer must be running a program which pulses the

Time-Out circuit at least once each second.

b) Reset the Time-Out circuit.

c) Check that the correct AC power source is available and

connected.

d) Check all fuses.

7.2 INCORRECT FREQUENCY INDICATION

a) Determine that the Zener-regulated voltages on the SlOOl

(Latch) card in the receiver are correct.

b) Determine that the load pulse for the latches on the

SlOOl card (pin 10 of U3 and U4) is entirely within the

duration of the Frequency Input pulse (pin 12 of Ul)

,

c) Determine that the Frequency Input pulse (pin 12 of UD

occurs at a 100 Hertz rate.

d) If only selected bits of the frequency are failing to

change as the receiver is tuned through its range, the

trouble may be a defective latch (U3 or U4) on the SlOOl

card or in the wiring.

7.3 TUNING LIGHT FAILS TO GO OUT

a) Follow advice in receiver manual.

b) Unplug the connector from PI of the SlOOl (Latch) card in

the receiver to determine if this card is affecting the

receiver's frequency synthesizer. If the tuning light

goes out, the fault is on the card, as the output functions of the receiver are disabled with this card removed.

7.4 NO AMPLITUDE OUTPUT TO COMPUTER

If the receiver appears to work properly, but there is no signal on the Amplitude output to the computer, J31:

38
a) Observe the input and output signals to AR2 and AR4 on the

SlOOl (Latch) card In the receiver. The gains should be

0.25 for AR2 and 10 for AR4.

b) If there Is an appropriate signal at the output of AR4,

but no signal at J31, there Is a wiring fault.

7.5 NO PHASE OUTPUT TO COMPUTER

If the receiver appears to work properly, but there is no signal on the Phase output to the computer, J26:

a) Observe the input and output signals to ARl and AR3 on

the SlOOl (Latch) card in the receiver. The gains should

be 1 for ARl and 2 for AR3.

b) If there is an appropriate signal at the output of AR3j

but no signal at J26, there is a wiring fault.

7.6 RF GAIN UNCONTROLLED IN AUTOMATIC

a) Using the chart in figure 11, try to identify if one or more relays on the S3001 card in the receiver are sticking or otherwise malfunctioning.

b) Determine that the decoder (Gain-Tracking-Phase card in

the ADACS chassis) is operating correctly to drive the

proper relays for each RF gain step.

c) Alternatively, repeat the tests in 5.3.1 and 6.2,3.

7.7 TRACKING RATE UNCONTROLLED IN AUTOMATIC

a) Observe the operation of the tracking rate controls in the

receiver by repeating 5.3.3. A failure of one of the

relays is the most likely cause of trouble.

b) Observe the operation of the decoder card in the ADACS

chassis by repeating 6.2.5.

7.8 BLANKING LEVEL UNCONTROLLED IN AUTOMATIC

a) Observe that the Blanking Level voltage can be made to cover its entire range by digital command. This voltage

is produced in the digital-to-analog converter on the

Blanking & INE card in the ADACS chassis. If the voltage

is not correct, disconnect the cable from J8 of the ADACS

chassis and measure the voltage again, as there may be

an excessive loading of the signal by a malfunction in the

receiver.

39
b) If the voltage is correct, the trouble may be in the relay

K15 on the S3001 card in the receiver.

c) If the voltage is incorrect, the trouble may be in the

digital-to-analog converter on the Blanking & INE card

or in the wiring to it.

7.9 PERCENT BLANKING INCORRECT

a) If the Percent Blanking output is always close to zero volts, there is probably a break in the wire bringing

Blanking Pulses from the receiver.

b) If the Blanking Level is changed so that the Blanking light

on the receiver seems to be continuously lit, the output

voltage for Percent Blanking should be over 1 volt.

c) If the Percent Blanking output is always about 10 volts,

the input signal at J6 is grounded, perhaps by a short.

8. TEST UNIT CONSTRUCTION

The Test Unit is constructed using a custom-modified cabinet

containing three printed circuit cards and numerous front panel

switches and indicators. The Test Unit contains the same circuit

functions as the ABACS Interface Chassis, whose functions it performs

in one mode of operation, plus the circuitry and switches necessary to

perform the functions of the computer.

The three cards in the Test Unit are: the Blanking & INE card

(S4001), the Gain-Tracking-Phase card, and the LED Driver card. The

first two are also used in the ADACS Interface Chassis. The LED Driver

card is used only in the Test Unit

.

8.1 BLANKING & INE CARD

8.1.1 CONSTRUCTION AND PARTS LIST

The construction of this card and its parts list are contained in sections 5.2.1 and 5.2.3, respectively, of the

Manual for Receiver and ADACS Interface Chassis (NBSIR 73-227).

£ 8.1.2 ADJUSTMENT

The circuit on this card for converting the Blanking

Pulses into an analog Percent Blanking voltage has both a zero setting and a full scale setting. The zero setting uses

a fixed resistor and the full scale setting uses an adjustable

pot.

40
Remove the cable (if any) to connector J6 and set the

Function switch to Percent Blanking. The voltage indicated on

the DVM (digital voltmeter) should be zero, plus or minus 50

millivolts. If not, a new value for R17 on the card is needed.

Use a higher value of resistance if the voltage is negative.

Connect a shorting cap to J6. Adjust R18A on the card to

give a DVM reading of +10.00 volts.

8.2 GAIN-TRACKING-PHASE CARD

The construction of this card and its parts list are contained

in sections 5.1.1 and 5.1.2, respectively, of NBIR73-227. There are

no adjustments to be made on this card.

8.3 LED DRIVER CARD

8.3.1 CONSTRUCTION

This card (figure 12) contains drivers to interface

incoming signal lines with the LED's on the front panel of the

Test Unit, and two one-shot circuits for the Phase-Change

Pulse and Interrupt signals. There are no special precautions

to observe in the construction of this card and the components

may be assembled in any order.

41
8.3.2 PARTS LIST (LED DRIVER CARD)

Designator

LED Driver

A, B, C

D, E

Rl

R3, R4, R6

R2f

R5

CI

C2

Quantity

1

18

Description

Printed circuit

card

Hex inverter,

open collector,

high current, TTL

Quad 2-lnput,

positive NAND

gates, TTL

Manufacturer

Divelpro

Texas

Instruments

Texas

Instruments

Part Number

C3

Integrated circuit, Fairchild

one shot

Resistor, 240 ohms, - 1/2 watt, +5%

Resistor, 5100 ohms,

1/2 watt, +5%

Resistor, 33K ohms, - 1/2 watt, +2%

Resistor, 39K ohms,

1/2 watt, +2%

Capacitor, 0.01 microfarad, +10% Sprague

Capacitor, 100. Sprague

microfarad, +10%

electolytic, 25 WVDC

Capacitor, 0.001 Sprague

microfarad, +10%

SN7406N

SN7400N

F9601

Pacer Fllmite

TE 1211

Pacer Fllmite

42
8.4 CHASSIS

8.4.1 CONSTRUCTION

The chassis for the Test Unit is a commercially available cabinet that is drilled and labelled for the mounting of

the necessary components. The front panel is drilled (figure

23) and labelled (figure 24) for the mounting of switches,

LED's (light emitting diodes), and the DVM (digital voltmeter).

The back panel is drilled (figure 25) and labelled (figure 26)

for the mounting of connectors. The floor of the chassis is

drilled (figure 27) for the mounting of the printed circuit

cards and power supplies.

The components are installed on the front panel as shown

in figure 28 and on the back panel as shown in figure 29. The

resistors for the LED's are soldered directly to the LED holders. Check each of the multi-pin connectors for a wellsecured nut in the center of the connector to hold the plug,

as some of the connectors have been delivered with a loose

nut that later became a nuisance whenever cables were changed

The printed circuit cards are mounted in sockets attached

to the floor of the chassis by angle brackets (figure 30). The

Gain-Tracking-Phase card is mounted on top of the LED Driver

card using straightened-out angle brackets between the card

sockets. The ends of the cards are kept off the floor of the

chassis and separated from each other by spacers. (Do not

mount the card sockets until later.)

It is quite difficult to tighten the screws to the

terminal strip on the 5-volt power supply when it is installed

in the chassis, so it is desirable to do some of the wiring of

the supplies with them on the work bench. Position the power

supplies on the bench as they will be in the chassis. Connect

all of the input wiring to both supplies (see figure 10)

Connect a single red wire to the +5 volt output and a single

black wire to the output common. The red and black wires

should be number 16 gauge and about 24 inches long. (The excess will be cut off later.)

Mount the power supplies using the correct spacers for

each supply (see figure 30). Both power supplies use 3/4-inch

long spacers, but one uses spacers with holes for number 6 screws and the other for number 8 screws. Do not tighten the screws until all screws have been started.

8.4.2 WIRING

While the electrical performance of the Test Unit is not

(except for the grounding) affected by the manner in which it

A3
is wired, the appearance of the finished wiring is dependent

upon the techniques used.

When the card sockets are wired, put each socket in a bench vise and solder the wires to each of the pins, observing

the color code. (It is much neater to make up the cable

harnesses this way than when the sockets are already mounted.)

Use shrink tubing about 1/8 inch in diameter over each of the

pins. Use excess wire length, which will later be cut back to

the proper length when the sockets are mounted. It is more

convenient to use cable ties to group wires going to different

connectors on the back panel.

The grounding technique used has all of the ground wires

connected directly to a single point on the chassis. The point

used is a long solder lug attached under the mounting screw

for one of the card sockets. (Typically, the mounting screw

for the Blanking & INE card nearest to the other card, as this

is a convenient place.) All ground wires are connected

directly to this lug, so some care must be used to conserve

space on the lug, as it may become a bit crowded. When mounting

the card sockets, scrape off the anodizing on the chassis

around where the ground lug will go and use appropriate lock

washers (with teeth) to ensure a good ground to the chassis.

The two terminal strips are used for mounting the resistor

and capacitor for the Manual switch. They should be mounted

near the card sockets.

Dress each group of wires going from adjacent card socket

pins to a particular back panel connector for a neat, equal

length appearance and cut to length. There is no need to seek

minimum length or to separate wires, as there are no electrical

problems. Attach the crimp pins and insert into the appropriate

slots of the connectors. The remaining wires may be cut to

length and soldered. Additional wires on the wiring diagram

that are not yet soldered should be installed now. The a.c. power wiring should be installed with shrink tubing over component contacts to reduce the chance of accidental electrical

shock. When using the coax from the BNC connectors, care should be taken in stripping them back and in soldering. (The

amount of heat required to solder the ground straps to ground

lug can easily melt the insulator and cause a short.) Use cable

ties as needed.

Before turning on a.c. power, check out the a.c. power

path visually. Then test with a.c. power, but without the

cards. Check for the correct voltage at the card pins. Adjust

the d.c. level with the power supply adjustment pots, if necessary. It is desirable to check out the wiring from the cards

to the back panel connectors using an ohmmeter.

44
Mount the cards in the chassis using the 1/2 inch spacers

to keep the ends of the cards off the bottom of the chassis,

and to keep the cards tightly into the sockets.

Certain commercial equipment and materials are identified in this

paper in order to adequately specify the components used. In no case

does such identification imply recommendation or endorsement by the

National Bureau of Standards, nor does it imply that the material or equipment identified is necessarily the best available for the purpose.

45
TEST UNIT W/RiN6

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50
TEST UNIT W/RiN6

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TEST UNIT WIRING

FROM TO COL OfK

tr3-A LED DR-WER ;8 BLACK

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52
TEST JNiT A/lRiNo

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53
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55
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56
8.4.3 PARTS LIST (CHASSIS)

Quantity

1

32

1

1

17

1

8

1

3

1

3

72

1

6

5

Description

Chassis with front and

back panels drilled and

labelled

Digital voltmeter for

panel mounting

Power supply +15 volts

400 mA

Power supply +5 volts

4 amperes

Indicator, light

emitting diode

Toggle switch

Rotary switch,

5 position, 1

pole, non-shorting,

steatite

Toggles switch, DPDT

Flush motor plug

(a.c. power)

Manufacturer

Optima

Newport

Lambda

Lambda

Dialight

J-B-T

Ceritralab

Alcoswitch

Amphenol

BNC connectors Amphenol

5 pin connector Amphenol

44 pin card sockets Amphenol

56 pin connector ELCO

20 pin connector ELCO

contacts for connectors ELCO

Extension cord Belden

Angle brackets H.H.Smith

Spacers, 1/2 inch H.H. Smith

high, no. 6 hole

Part Number

K-051716HT

Gray No. 26440

Trim No. 26152

200A with option A3

LXD-3-152

LXS-A-5-0V

249-7868-3331-504

ST22N

PA2001

MST215N

160-5-N

31-221

126-010

225-22221-101

00-8016-056-000-001

00-8016-020-000-707

60-8017-0313

17461

1476

2112

57
8.4.3 (Cont'd)

Quantity Description

4 ^ Spacers, 3/4 inch

high, no. 6 hole

^' 4 Spacers, 3/4 inch

high, no. 8 hole

r 58

Manufacturer Part Number

H.H.Smith 2113

H.H.Smith 2118
8.4. 3 PARTS LIST (CHASSIS) (Cont'd)

Quantity Description Manufacturer Part Number

1 Capacitor, 0.47 microfarad Spague Pacer Filmite

1 Resistor, 27 ohm, 1/2 watt,

2 percent

18 Resistor, 240 ohms, 1/4

watt, 5 percent

1 Feedthrough lug to be used Vernitron 14301

as ground lug

1 Fuse holder, 3AG extractor Littlefuse 342012A

post

1 Fuse, 1/2 ampere, slow blow Littlefuse 313.500

3AG

2 Tie down terminals, used as H.H.Smith 863

terminal strips

Quantity Thread Description

12 2-56 5/8 inch long fillister head brass machine screw

12 2 washer, cadmium plated steel, internal teeth

12 2-56 brass hexagon nut

6 4-40 1/2 inch long fillister head brass machine screw

4 4-40 1/2 inch long round head brass machine screw

4 4 washer, cadmium plated steel, round flat

8 4 washer, cadmium plated steel, internal teeth

8 4-40 brass hexagon nut

2 6-32 1 and 3/4 inch long flat head brass machine screw

5 6-32 one inch long flat head brass machine screw

4 6-32 3/8 inch long flat head brass machine screw

3 6 washer, cadmium plated steel, round flat

59
8.4.3 (Cont'd)

Quantity Thread Description

7 6 washer, cadmium plated steel, internal teeth

7 6-32 brass hexagon nut

4 8-32 one inch long flat head brass machine screw

Certain commercial equipment and materials are identified in this

paper in order to adequately specify the components used. In no case

does such identification imply recommendation or endorsement by the

National Bureau of Standards, nor d es it imply that the material or equipment identified is necessarily the best available for the purpose.

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1

U.S. L)t.p-i. OF co-.M. 1. PUBLICATION' OP h;-:port ^o.

BliluiOGRAI hIC DATA NE'^IR 7t— '''^'^

2. '.io\ 'r Acccr-rion No.

3. Recipient's Accession No.

nT!J: AND SUBTM'J-;-: riELD SERVICE TEST MODEL: COMPUTER-COKTROLLED U SYSTEM

MKUAL FOR TEST UNIT

5. Publication Date July 11, 1973

fi. Pcrif^rmiag C>r gani.'rati on Coue

j

AUTHOR(S) R. J. Carpenter, K. M. Gray

D. S. Gr'jbb and L. J. Pfelombo

8, Pcri'oriu'ng Organ iz.-it ion NBSIR 73-236

PFRl- ORMI.vIG ORGANIZATION NA.ViE AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Projeci/Tasl./V.'ork Unit Nc. 6505413 -

11. Contract/Grant No. AFTAC T/2301/U/NBS

. Spoasorir^t', Organization Name and Address Department of the Air Force

HQ USAF (AFTAC/TAP)

Patrick A. F.B. , Florida 32925

ij. 1 ype or Kcport o: Period Covered Instruction Manual

1<J. Sponsoring Agency Code

Tsrsi-; PLEMENTARY NOTES

It'. ABSrR.\CT ( -A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) This manual describes the construction and use of a highly specialized test unit for

usF- with certain computer-controlled very low frequency receivers and their associated

inteirface (ALACS) units.

17. KEY \V0R1>S (Aljjhab^-tical order, separated by semicolons)

ADACS interface chassis; computer-controlled VLF receivers; test unit; U system

IB. AVAILABILITY STATEMENT

UNLIMITED.

[XI FOR Ol- FlCiAI DISTRIBUTION. DO NOT RELEASE

TO NTIS.

19. SI^CURI TY CLASS

(Tins REPORT)

UNCLASSIFIED

20. Si;CURITY CLASS

Ci'HlS PAGE)

UNCLASSIFIED

21, NO. OF PAGES

22. Price