TM 11-5820-801-30
trace approaches the upper reference level (fig. 3-9).
(3) On Pump Source Module 2A1 front panel,
The CN-1367/U dial indication minus 10 is the cold
remove the cover plate by removing four Phillips head
insertion loss of Amplifier, Parametric AM-6602/MSC-
screws, thereby exposing attenuator controls AT3 and
46(V) It shall be 4 dB or less and is assumed to be 0.5
AT4 (fig 3-11).
dB greater in the first stage (2A3) than in the second
(4) Unlock 2A1AT3 attenuator control by
stage (2A2) (for gain computation purposes).
loosening the lock thumbscrew (right angles to the
(b) Reset toggle switches 1S4 and IS5 to 1ST
attenuator control) Then, with a hex wrench, turn AT3
STG ON and 2ND STG ON, respectively.
attenuator control while observing the oscilloscope
c. Gain-Bandwlth .Alignment Procedure.
Adjust for optimum gain (approximately that shown in
(1) Gain-bandwidth alignment shall be made
(5) Turn the IST STG BIAS IR5 adjustment
after the gain-bandwidth tests indicate that either the first
stage (2A3) (b(l), (11), and (12) above) or the second
control (fig 3-3) with a screwdriver while observing the
Adjust for
optimum
(approximately that shown in figure 3-9).
characteristics are out of tolerance Maintain the test
(6) Because the effects of the 2A1AT3 and
setup of figure 3-8 (b(6) above).
1R5 adjustments react on each other to some extent it
(2) If the first stage (2A3) characteristics are
may be necessary to repeat (4) and (5) above one or
out of tolerance proceed as follows. Set toggle switch
more times to obtain the optimum gain-bandwidth
1S5 to BYPASS (fig. 3-3) Display the gain-bandwidth
response Stage gain shall be 13.5 1 dB over 500 .MHz
response curve on AN/USM-273 as in b(l 1) above An
example of an out-of-tolerance gain-bandwidth response
band Refer to b(12) above.
is shown in figure 3-10
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