User Manual

ALIGNMENT PROCEDURE AND PERFORMANCE TESTS
6-2
June 1997
Part No. 001-3412-002
6.3.3 MODULATION ALIGNMENT
1. Connect a DC voltmeter to the junction of R822/
R823 and adjust R823 for 2.10V DC ±0.05V DC
(see Figure 6-4).
2. Inject a 100 Hz square-wave tone at approximately
0.35V P-P, biased at +2.5V DC on J201, pin 6.
3. Transmit into the modulation analyzer and observe
modulation output on the oscilloscope. Set the
modulation analyzer high pass filtering off and no
less than a 15 kHz low pass filter.
4. Adjust R827 for a flat square-wave on the
oscilloscope. (The voltage at the wiper of R827
should be between 1-3V DC. If the voltage is less
than 1V DC, replace R825 with a larger value.)
5. Inject a 100 Hz sine-wave on J201, pin 6, biased at
+2.5V DC, the modulation analyzer should still
have the 15 kHz lowpass filter selected.
6. Adjust the audio analyzer output level to achieve a
transmit deviation of:
1.5 kHz for 12.5 kHz BW (-X10 Radios)
3.0 kHz for 25.0 kHz BW (-X30 Radios)
7. Set a 0 dB reference of FM peak deviation on the
Audio Analyzer.
8. Input a 1kHz sine-wave. The level should be within
±1.5 dB of the reference at 100 Hz.
0.2V RMS for 12.5 kHz BW (-X10 Radios)
0.4V RMS for 25.0 kHz BW (-X30 Radios)
9. Remove transmit modulation and unkey the
transmitter.
6.3.4 TRANSMITTER AND FREQUENCY ALIGN-
MENT (Johnson Loader Using Diagnostics)
NOTE: Subtract the current drawn by the test loader
or any interface units from all measurements.
NOTE: Refer to DL-3240 Universal Loader Board
Service Manual for software description and program-
ming information. The PRODUCTION TEST : TEST
SELECT menu is required for alignment.
1. Check that R571 is installed and R572 is removed
on Revision 2 or earlier boards (see Figure 6-4).
2. Make sure input supply voltage equals +13.3V.
3. Arrow to the "mid" channel.
4. Press F5 to key the transmitter (see Figure 6-2).
5. Adjust R535 fully clockwise for maximum power
output.
6. Adjust the DAC value using PgUp/PgDn to set the
power out to 5.0W ±0.3W. Re-check supply volt-
age for +13.3V. Adjust voltage and power if neces-
sary (see Figure 6-2).
7. Repeat Step 6 at the "low" and "high" channels.
8. Power output should be 4.7-5.3W (50% Duty
Cycle) and current less than 2.5A for 380-512 MHz
Transmitters.
9. Arrow to the "mid" channel. Adjust the frequency
displayed on the Frequency Counter to read accord-
ing to the frequency shown on the monitor by
adjusting the TCXO (Y801).
10.Observe the Forward Power voltage on the monitor.
The voltage should be greater than 3.0V DC.
11.Observe the Reverse Power voltage on the monitor.
The voltage should be less than 1.0V DC.
6.3.5 MODULATION ADJUSTMENT
1. Arrow down to Square Wave and arrow over to tog-
gle the 100 Hz square-wave tone on.
2. Transmit into the modulation analyzer and observe
modulation output on the oscilloscope. The modu-
lation analyzer should not have any high pass filter-
ing selected and no less than a 15 kHz low pass
filter.
3. Check to be sure the DAC values are at there initial
settings. Press F3 to initialize the Power Adjust,
Mod Adjust, and Front-End Adjust if they are not
initialized (see Figure 6-2).