TM 11-6625-1633-45
d. Set the controls of the AN/URM-149 as follows:
(1) POWER OFF toggle
quency.
switch:
ON (up)
k. Observe that frequency meter zero beat is within
(2) INTERNAL MODULA-
the limits specified in the chart below:
TION FREQUENCY
selector switch:
20 kc
MINIMUM
MAXIMUM
990 Hz
1010 Hz
(3) DEVIATION METER
15.84 Hz
1616 Hz
RANGE selector switch:
300 kc
19.8 KHz
20.2 KHz
(4) MODULATION selector
67.32 Khz
68.68 KHz
switch:
INT SINE
106.92 KHz
109.08 KHz
e. Set the Spectrum Analyzer 723/U POWER switch
5-13. RF Noise Level Test
to DN.
f. Normalize the AN/URM-149 by setting the FRE-
b. Allow the equipment a 2 hour warmup period be-
QUENCY MC counter for an indication of 600 MHz.
fore starting procedure.
g. Adjust the ME-57/U TUNING control for a
c. Set controls of Modulation Meter ME-57/U as
maximum deflection of LIMITING meter, with the
follows:
CARRIER SHIFT meter indicating zero.
(1) POWER:
ON (up)
(2) FREQUENCY RANGE:
500-1000
Figure 5-3. Internal modulation frequency accuracy, test setup diagram.
5-7
