Service manual

ALIGNMENT PROCEDURE AND PERFORMANCE TESTS
7-5
April 2001
Part No. 001-9800-203
4. Continue with the instructions on the screen to set
the Low Power Level for a value within the
preceding ranges. One low power level can be
programmed with low tier models, and four levels
can be programmed with high tier models.
7.3.5 MODULATION BALANCE
1. Manually select “Modulation Balance” or automat-
ically select “Tune Modulation Balance”.
2. Connect a 50-ohm load to the antenna jack and view
the transmit modulation waveform on the CRT of a
communication monitor. If applicable, set the
monitor for de-emphasis off, high-pass filter off,
low-pass filter 3 kHz, and FM peak detection active.
3. Set the monitor for the indicated frequency and
follow the instructions to adjust for the best demod-
ulated square wave with minimum tilt and over-
shoot. Repeat for the other standard and talk-around
frequencies indicated.
7.3.6 TRANSMIT AUDIO LIMITING
1. Manually select “Audio Deviation” or automati-
cally select “Transmitter Audio Deviation”.
2. Apply a 1 kHz, 1 volt rms, AC coupled signal to the
transmit audio input jack of the RPI as shown in
Figure 7-1.
3. Monitor the transmit modulation signal with a
communications monitor. If applicable, set the
monitor high-pass filter for 50 kHz and the low-pass
filter for 15 kHz.
4. Follow the instructions on the screen and set wide-
band (UHF and 800 MHz only) deviation for 3.7
kHz ±50 Hz and narrowband deviation for 1.5 kHz
±50 Hz on the low and high channels. With 800
MHz models, the NPSPAC channel deviation is also
set for 2.9 kHz ±50 Hz. Remove the 1 kHz injection
signal.
7.3.7 TRANSMIT DATA LEVEL
1. Manually select “Data Deviation” or automatically
select “Transmitter Data Deviation”.
Figure 7-4 Alignment Points Diagram
2. Continue monitoring the transmit modulation signal
with a communications monitor set the same as in
the preceding section.
3. Follow the instructions on the screen and set the
wideband (UHF and 800 MHz only) deviation for
1000 Hz ±50 Hz and the narrowband deviation for
800 Hz ±50 Hz on the low and high channels.
7.3.8 RECEIVER IF ADJUSTMENT
1. Manually or automatically select “Receiver
Adjustment”.
2. Connect an RF signal generator to the antenna jack
using a 6 dB or greater pad. Set the generator output
for the displayed frequency, modulated with 1 kHz
at 3 kHz deviation.
J201
L218
Ref Osc Freq.
L215
L213
Pin 20
Pin 19