Service manual

8000 SERIES RECEIVER DECODER MODULE (RDM)
2-7
March 2000
Part No. 001-3139-502
Figure 2-5 900 MHz RECEIVER ALIGNMENT POINTS DIAGRAM
2.10 900 MHz RECEIVER PERFORMANCE
TESTS
2.10.1 SINAD SENSITIVITY
1. Set the RF signal generator to the channel fre-
quency, modulated with 1 kHz at ±1.5 kHz devia-
tion. Connect the generator to the receiver antenna
jack.
2. Connect a SINAD meter to the AUDIO TEST jack
on the front panel of the receiver.
3. Increase the generator output to obtain a SINAD of
-12 dB. The generator output should be 0.35 µV or
less.
4. If using diversity antennas, connect the generator to
the other antenna jack and sensitivity should be the
same.
2.9 900 MHz RECEIVE DATA LEVEL ADJUST-
MENT
1. Connect a signal generator to the receiver antenna
jack, see Section 2.8.6. Set the generator to the
receive channel frequency with an output level of
100 µV, modulated with 150 Hz at ±800 Hz
deviation.
2. On the Logic Drawer, connect an AC voltmeter or
oscilloscope between TP8 and chassis ground.
Adjust R81 for 0.56V P-P (±0.05V) or 0.20V RMS
(±0.02V) at TP8.
3. Connect a DC voltmeter to TP8 on the Logic
Drawer and adjust T5 on the Receiver Drawer for a
meter reading of 4.0V DC ±0.2V.
4. Repeat Step 2.