Receiver Frequency and Bandwidth Using AN/UPM-137A

TM 11-6625-667-45/NAVAIR 16-30APM123-2/TO 33A1-3-367-22

7 - 4 . 1 . Receiver Frequency and Band-

j. Decrease AN/UPM-137A SIS generator

TRIGGERS-DELAY TRIG (SEC)-MULT 1-11 con-

width Using AN/UPM-137A

trol until top of pulse displayed on CHAN A reaches

Connect the equipment as shown in figure 7-1.1.

center graticule. Note frequency at this point as f.

Set and adjust the controls as described in para-

k. Increase AN/UPM-137A SIS generator TRIG-

graph 7-3.2.

GERSDELAY TRIG (SEC}MULT 1-11 control

a. Disconnect cable from set set test point

until top of pulse displayed on CHAN A again

A5TP5 and connect to AN/UPM-137A interrogator

reaches center graticule. Note this frequency as F2.

signal simulator TRANSMITTER-SWEEP SYNC

l. Subtract F1 and F2 to determine 3 dB band-

OUT jack.

width, It should be 6.5 1 MHz.

b. Connect AN/UPM-137A interrogator signal

m. Add F1 to F2 and divide by two to determine

simulator TRANSMITTER-SWEPT FREQ MARK-

the center frequency, it should be 1,090 0.5 MHz.

ERS jack to AN/UPM-137A oscilloscope VERTI-

CAL CHAN B-VIDEO IN jack,

7-5. Receiver Sensitivity Using AN/

c. Connect AN/UPM-137A oscilloscope VERTI-

UPM-98

CALCHAN AVIDEO IN jack to test set test

a. Connect the equipment as shown in figure 7-1

point A8TP2.

and adjust the controls as described in paragraph

d. Set AN/UPM-137A interrogator signal simu-

7-3.

lator TRANSMITTER-XMTR FREQ switch to

b. Remove the cable from the PROBE input on

SWEEP, SIS generator PRF-RANGE MULT switch

the AN/APM-123 and connect it to the TS-779/U

to EXT +, SIS generator TRIGGERS-DELAY TRIG-

through the MX-2144A. Remove the modulation

GERS-DLY RANGE MULT switch to X400, SIS

and the bias voltage and measure the output

generator TRIGGERS-DELAY TRIG (SEC)-MULT

wattage. Set the output of the AN/URM-64 for -9

1-11 control to 4.6, oscilloscope HORIZONTAL

dBm.

SYNC switch to EXT DC +, oscilloscope HORI-

c. Connect the output cable from the MD-796

ZONTAL-TIME/DIV switch to 50 sec, and rf signal

back to the PROBE jack. Reapply the bias and mod-

generator OUTPUT ATTEN 0-100 dBm to -10.

ulation connection.

e. Adjust AN/UPM-137A SIS generator TRIG-

d. Adjust control A8R5 until an ACCEPT condi-

GERS-DELAY TRIG (SEC)-MULT 1-11 control for

tion is obtained.

maximum a m p l i t u d e of signal display on

AN/UPM-137A oscilloscope GHANA.

7-5.1. Receiver Sensitivity Using AN/

f. Adjust AN/UPM-137A rf signal generator

UPM-137A

OUTPUT ATTEN 0-100 dBm control until signal

Connect the equipment as shown in figure 7-1.1.

displayed on AN/UPM-137A oscilloscope CHAN A

Set and adjust the controls as described in para-

just saturates.

graph 7-3.2.

g. Adjust AN/UPM-137A rf signal generator

a. Set AN/UPM-137A rf signal generator OUT-

OUTPUT ATTEN 0-100 dBm control -3 dBm

PUT ATTEN 0-100 dBm control to - 15dBm and

from setting of f above.

then slowly adjust cw until test set ACCEPT indi-

h. Adjust AN/UPM-137A oscilloscope VERTI-

cator just lights.

CAL-CHAN B-VERT POSN control until top of

b. Add AN/UPM-137A rf signal generator OUT-

pulse coincides with center horizontal graticule.

PUT ATTEN 0-100 dBm control setting to cable and

i. Adjust AN/UPM-137A rf signal generator

tenuation marked on cable connected to test set

OUTPUT ATTEN 0-100 dBm control to setting of f

PROBE jack to determine sensitivity. Sensitivity

above.

should be -9 1 dBm.

NOTE

If necessary, adjust the sensitivity by first

Frequency is determined by using swept

adjusting the AN/UPM-137A rf signal

frequency markers as a reference and ex-

generator OUTPUT ATTEN 0-100 dBm

trapolating. The center marker is 1090

control to -9 dBm minus the attenuation

MHz and the markers on each side are 3,5,

marked on the cable connected to the test

10, and 29 MHz, respectively, from the

set PROBE jack and then adjusting test set

center marker.

Change 4

7-5