TM
115826-225-35
c. Receiver Waveforms. Typical waveforms
at significant points in the receiver are s h o w n
in figure 2 18. Use oscilloscope AN/USM-140
when obtaining data for comparison with the
waveforms shown in figure 218. The wave-
forms in figure 218 were obtained under the
following conditions:
(3) The 150PF270PF control on the
(6) For bfo Q21, do not connect RF Signal
sense antenna adapter is set to
Generator AX URM25( ) and set
150PF.
the BFOOFF switch on the test set
to OFF.
Q24,
adjusted to obtain a waveform similar
a n Q 2 5 is o b t a i n e d w i t h s e r v o m o t o r
locked. After B5 is locked, by
B5
b l o c k i n g the gear train, adjust the
taken with Rf Signal Generator AN
URM-25( ) connected to the test set
as shown in figure 22. The AN
URM-25( ) is tuned for 200 kc (set
BFOOFF switch on the test set to
ON and tune AN/URM-25( ) for a
(8)
z e r o beat in t h e h e a d s e t , t h e n s e t
B F O - O F F switch to OFF). The AN
U R M - 2 5 ( ) output is then adjusted
for 1,000 microvolts, modulated 30
percent at 400 cps.
235
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