E.F. Johnson Company CONVENTIONAL VOTING RECEIVER, User Manual

Page: 78 / 148

800 MHz RECEIVER
4-10
July 2000
Part No. 001-2000-720
9. The software programs the synthesizer for
3 MHz below the Receive Channel.
10.Receive sensitivity should be less than 0.35
µ
V
(typically less than 0.30
µ
V).
11. The software programs the synthesizer for the
Receive Channel.
4.4 FULL CVR TEST
1. Select TEST - FULL RPTR/STATION/CVR and
press Enter.
NOTE: All audio generators and audio voltmeters are
unbalanced unless specifically stated otherwise.
4.4.1 VOLTAGE MEASUREMENTS
1. Disconnect the receiver-to-interface cable
(20-pin) from J201 of the Interface board.
2. Apply power to the Interface board.
3. Measure the voltages at the following pins.
U109, pin 1 +12V DC
±
0.4V
U223, pin 2 +9V DC
±
0.4V
U224, pin 2 +5V DC
±
0.2V
U204, pin 7 +1.25V DC
±
0.06V
Junction of L202/C279 -5V DC
±
0.4V
4. Apply power to the Receiver by plugging the 20-pin
cable from the Interface Board into J201 (see
Figure 4-28
).
4.4.2 RECEIVER FREQUENCY CHECK
1. Check the receiver injection frequency with a
"sniffer" pickup loop, or RF probe and a suitable
frequency counter placed near L210.
2. TCXO Adjustment
Set Y201 (TCXO) for the Injection Frequency
±50 Hz (Inj Freq = chnl freq - 52.95 MHz).
Receiver Audio Distortion Measurement
1. Adjust the RF generator for 100
µ
V into the receiver
with a 1 kHz tone at
±
3 kHz deviation.
2. Adjust R207 for 0 dBm (775 mV RMS) at J210.
3. Connect a 16 ohm load and distortion analyzer to
J204 of the Interface Board.
4. Adjust R262 for 2.8V RMS and measure the distor-
tion. Distortion should be < 3%.
Receiver Hum and Noise Measurement
1. Adjust the RF generator for 100
µ
V into the receiver
with a 1 kHz tone at
±
3 kHz.
2. On the Interface Board, connect a 16 ohm load and
distortion analyzer to J204.
3. Adjust R262 for 2.8V RMS.
4. Remove modulation from the RF generator.
The measured level must be
≤
-45 dB.
Receiver SINAD Measurement
1. Adjust the RF generator for 100
µ
V into the receiver
with a 1 kHz tone at
±
3 kHz.
2. On the Interface Board, connect a 16 ohm load and
distortion analyzer to J204.
3. Adjust R262 for 2.8V RMS.
4. 12 dB SINAD reading should be
≤
0.35
µ
V.
Receiver Squelch Adjustment
1. Adjust the RF generator for 100
µ
V into the receiver
with a 1 kHz tone at
±
3 kHz.
2. On the Interface Board, connect a 16 ohm load
and distortion analyzer to J204.
3. Adjust R262 for 2.8V RMS.
4. Set the RF generator output for 5 dB SINAD.
5. On the Interface Board, adjust R222 so the Receiver
just squelches.
6. Increase the RF generator output until the Receiver
unsquelches. Reading should be
≤
10 dB SINAD.