Viking VX 900 MHz LTR, User Manual

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ALIGNMENT AND TEST PROCEDURES
7-16
October 1999
Part No. 001-2009-201
3. Offset Channel Selectivity
4. Intermodulation Rejection
5. Spurious Rejection
6. Audio Response
7. Audio Sensitivity
Perform the Test desired using the appropriate RF
Generators, modulation frequencies and levels, R236
levels and test probes.
7.6.5 RECEIVER EXPANDER MEASUREMENT
NOTE: This test is valid only with compandor option
installed.
1. Adjust the RF generator for 100
µ
V into the
receiver with a modulation tone of 1 kHz at
±
1.5 kHz deviation.
2. Insert AC voltmeter probes into J100/J103 on the
MAC. AC voltage shall be between 1.1 and 1.25V
RMS.
3. Adjust RF generator for
±
800 Hz deviation. AC
voltage shall be between 325 and 450 mV RMS.
4. Adjust RF generator for
±
500 Hz deviation. Volt-
age level shall be between 150 and 250 mV RMS.
7.6.6 TRANSMIT AUDIO/DATA LEVEL ADJUST-
MENTS
NOTE: All audio generators and audio voltmeters are
unbalanced unless specifically stated otherwise.
Audio Deviation Limit Adjustment
1. Remove VNC cards if present.
2. Apply a 1 kHz tone at -3 dBm (548 mV RMS) to
P100, pin 32 of the MAC.
3. Insert test cables into J100/J103 and connect to an
AC voltmeter.
4. Press the space bar to key the transmitter.
5. Adjust R305 for 0 dBm (775 mV RMS).
6. Press the space bar to unkey the transmitter.
7. Press F2 to advance to the next screen.
8. Final adjustment must be performed on the cus-
tomer channel. Apply a 1 kHz tone at +7 dBm
(1.73V RMS) to P100, pin 32 of the MAC. (Set
modulation analyzer LPF switch to 3 kHz.)
9. Press the space bar to key the transmitter.
10.Adjust U149 with the PgUp/PgDn and CurUp/
CurDn keys to set the maximum allowed deviation
at
±
1.6 kHz
±
50.
11. Press the space bar to unkey the transmitter.
12.Remove the signal from P100, pin 32.
Repeat Audio Level Adjustment
NOTE: Audio Deviation Limit Adjustment must be
completed before this test.
1. Adjust the RF generator for 100
µ
V output with a
1 kHz tone at
±
800 Hz deviation. Set modulation
analyzer LPF switch to 3 kHz.
2. Press the space bar to key the transmitter.
3. Final adjustment must be performed on the cus-
tomer channel. Adjust R237 on the MAC to
achieve
±
800 Hz (
±
50 Hz) transmit deviation.
4. Press the space bar to unkey the transmitter.
5. Press F2 to advance to the next screen.
6. Connect an AC voltmeter to J103 and P100, pin 31
(RX_VOICE).
7. Adjust R238 for -3 dBm (548 mV RMS).
8. Remove the RF generator from the Receiver.
Data Level Adjustment
1. Remove VNC cards if present. (Set modulation
analyzer LPF switch to 3 kHz.) Final adjustment
must be performed on the customer channel.