Figure 4-8. AN/PRR-S(XE-9) if. selectivity test.

TM 11-5820-549-50-1

Figure 4-8. AN/PRR-S(XE-9) if. selectivity test.

i. Return AN/GRM-50 to 455 kHz and tune each

d. Adjust the receiver volume control for squelch

side of 455 kHz until the ME-26/U indicates 0.6 volts

"off" and midposition.

difference from reference level noted in step f. above.

e. Adjust the AN/GRM-50 output for 500

j. Note and record the 0.6 volt difference

microvolts.

frequency, as indicated on the AN/USM-207.

f. Note and record the voltage reading on the ME-

k. Determine the Af, and Af, of each 0.6 volt

26/U. This is the reference level for the test.

difference frequency.

g. Vary the frequency of the AN/GRM-50 on each

I. The asymmetry ratio of the discriminator shall

side of 455 kHz until the ME-26/U indicates maximum

not exceed 1.3:1.

difference from the reference level noted in step f.

above.

h. Note and record the frequencies at which

maximum difference occurs, as indicated by the

AN/USM-207. The peak to peak separation shall be at

least 40 kHz.

4-6