Racal Instruments RA6790/GM, Техническое руководство

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Racal RA6790/GM Alignment & Tuning Manual
Page 9 of 20
and the Meter Range to +10 dB (1 mW).
(18) Select the FM mode, adjust the AM/FM signal generator frequency for 1.5
MHz with an output of -40 dBm and modulate the signal at 1 kHz
with a peak deviation of +4 kHz. Check the audio output indication on the
distortion analyzer meter. Adjust coil L3 for peak audio output.
(19) Turn Receiver off. Disconnect all test equipment and replace filter assembly
cover.
f. ISB IF/AF, Circuit Card Assembly A5.
This circuit card is an optional assembly and may not be pre s ent in all Receivers. If
it is used, the A5 assembly is ins talled in the top portion of the Receiver, towards
the rear. The test equipment required to align the A5 module includes the spectrum
analyzer, AM/FM signal generator, digital multimeter, and RF
Millivoltmeter,
shown in Table 1-2.
NOTE
The LK 1 link on the A4 circuit card must be ins t alled for ISB operation and the
alignment procedures for A4 must be performed prior to any adjustment on the A5
circuit card.
(1)
Connect the AM/FM signal generator to Jl-RF IN on the rear
panel. Turn the Receiver on and adjust frequency to 1.5000 MHz, AGC to
MAN, IF gain to maximum and mode to LSB.
(2) Connect the high impedance test probe of the RF millivolt-
meter to TP7 on circuit card A5. Set the AM/FM signal generator to 1.4982
MHz at an output level of 30 uVolts (-73 dBm).