Rf Synthesizer Module (A9) - Motorola R-20010 Maintenance Manual

NOTE
If a National Bureau of Standards
radio station is receivable, the fol -
lowing procedure can be per-
formed.
1.
Remove the timebase-calibration cover screw on
the lower left side of the System Analyzer.
2. Allow t he Analyzer to warm up for at least 20 min-
utes.
3. Select Monitor AM function and Gen/Mon Mtr
display. Set the monitor frequency to one of the
National Bureau of Standards radio stations (5, 10,
15,
or 20 MHz), and use
a
suitable antenna for
these frequencies.
4. Adjust the time base for a reading of 0 Hz ± 1 Hz
on the CRT monitor frequency-error display.
3.3.6 DUPLEX GENERATORS
3.3.6.1 Duplex Generator
1. Remove the bottom cover of the System Analyzer
and the Duplex Generator cover.
2. Select Generate FM function and Duplex Gen dis-
play. Set the DUPLEX GEN switch to ON, the
Duplex monitor frequency to 145 MHz, the offset
freq uency to 45 MHz, and the Image/Dplx switch
to
Low.
3. Adjust C68 on the Duplex Generator board (Figure
3-5) for 8 to 10V, as measured at TP
1.
4. Connect the calibrated external modulation meter
to the DUPLEX GEN Output port on the front
panel. Tune the external modulation meter to 100-
MHzFM.
5. Turn on the Modulation 1 kHz Level switch and
adjust for a reading of 20 kHz on the CRT gener-
ate-deviation display. .
6. Adjust R69 on the Duplex Generator board (Figure
3-5) for a reading of 20 kHz ± 1 kHz, as measured
by the external modulation meter.
7. Set the Duplex offset frequency to 0 Hz Select
Monitor FM function and Gen/Mon Mtr display.
8. Connect the DUPLEX GEN Output port to the
Antenna port on the front panel.
9. Adjust C40 on the Duplex Generator board (Figure
3-5) for a reading of 0 Hz ± 50 Hz on the CRT
monitor frequency-error display.
3.3.6.2 Enhanced Duplex Generator
1. Remove the bottom cover of the System analyzer
and the Duplex Generator cover.
2. Select Generate FM function and Duplex Gen dis-
play. Set the DUPLEX GEN switch to ON, the
Duplex monitor frequency to 145 MHz, the offset
frequency to 45 MHz, and the Image/Dplx switch
to
High.
3-1 1
3. Adjust C68 on the Enhanced Duplex Generator
board (Figure 3-10) for 8 to lOV, as measured at
CR14.
4.
Connect the calibrated external modulation meter
(HP8901) to the DUPLEX GEN Output port on
t he front panel. Tune the external modulation
meter to 145 MHz FM.
5. Turn on the Modulation 1 kHz Level switch and
adjust for a reading of 20 kHz on the CRT gener-
ate-deviation display.
6. Adjust R69 on the Enhanced Duplex Generator
board (Figure 3-10) for a reading of 20kHz ±50
Hz, as measured by the external modulation meter.
7.
Select Monitor FM function and Gen/Mon Mtr
display.
8. Connect the DUPLEX GEN Output port to the
Antenna port on the fro nt panel.
9. Adjust Yl on the Enhanced Duplex Generator
board (Figure 3-10) for an error reading on the
CRT monitor frequency-error display equal to the
offset stamped on Yl ± 10 Hz.
3.3.7 WIDEBAND AMPUFIER
NOTE
Perform extended alignment pro-
cedures 3.3.1A Peak Detector Zero
and 3.3.1C DVM before making the
following alignment.
1. Remove the RF input module (A17) from the sys-
tem analyzer and remove the wideband amplifier
cover from t he RF input module. Reconnect the
ribbon cable connector and the coax cable coming
from the RF synthesizer module (A9) to the A17
module.
2. Select the Generate FM function, Gen/Mon Mtr
display, and turn all modulation OFF. Set the
Generate Frequency to 500.0000 MHz.
3. Select the Antenna Port and set the step atten-
uator to the 0 dB position.
4. Connect a calibrated wattmeter (HP4364) to the
Antenna Port.
5. Adjust the RF variable level control on the front
panel for a reading of 10.00 dBm on the external
wattmeter.
6. Adjust R34 (OFFSET) on the wide band Amplifier
board (see Figure 3-11) for a reading of 10.0 dBm
±
0.2 dBm on the CRT RF level display.
7. Adjust the RF variable level control on the front
panel for a reading of 1.00 dBm on the external
wattmeter.
8. Adjust R38 (GAIN) on the wideband Amplifier
board for a reading of 1.0 dBm ± 0.2 dBm on the
CRT RF level display.