Transmitter Output Pulse Test - TM-11-6625-667-450121

f. Set the RANGE switch to-10 DBM and

f. Meter deflects slightly

right

(ap-

readjust zero set course and fine con-

proximately -21

trols to zero meter. Reconnect the MX-

dbm).

2144A/U to the AN/APM-123 PROBE

connector. Observe the power meter

reading.

Remove the jumper from A4TP4 to

ground.

5-5. Transmitter Output Pulse Test

a. Test Equipment Required

(1) Oscilloscope, AN/USM-281A.

(2) Test Facilities Set, Transponder Set AN/APM-270.

b. Test Connections and Conditions. Connect the equipment as shown in B, figure 5-3.

c. Procedure.

Control settings

Test

Equipment under

Performance

Step

test

Test equipment

procedure

standard

AN/USM-281A

a. Turn on the oscilloscope and test set.

a. None.

FUNCTION: SYSTEM.

POWER: ON

Pemit a few minutes warmup.

ISLS: ON.

b. None.

Sweep delay switch Delayed.

b. Press the test set PRESS-TO-TEST

POWER ON.

Delayed TIME/DIV: 5 sec

PRESS-TO-TEST: LOCK.

switch and turn to LOCK.

Main TIME/DIV: .5 sec

MODE: 1.

c. Adjust the oscilloscope as follows:

c. See (1) through (9)

Sweep Mode: AUTO

below.

Main SLOPE: -

( 1 ) Pulse widths:

(1) Adjust t h e H O R I Z O N T A L

0.8 0.1 s e c .

Delayed SLOPE: -

position control until the .50%

DIV DELAY: 02

point of the first pulse leading

Main Trigger Source switch: EXT

edge is positioned at the center

DISPLAY: A

graticule line. Measure the pulse

A VOLTS?DIV 5

width.

A POLARITY: UP

(2) Delay between

(2) Adjust the oscilloscope controls to

A Input coupling switch: AC

measure the delay between the

P1 and P2 shall

be 2 0.2 sec.

50% points of pulses Pl and P2.

(3) Adjust the oscilloscope control to

(3) Mode spacing:

3 0.2 sec.

measure the delay between pulses

Pl and P3 at the 50% points of

the leading edge.

d. Set the test set MODE switch at each of

d. None.

the positions, in (1) through (4) below

and repeat the procedure in c (3) above

to measure delays between P1 and P3.