Sony SPP-904, Service Manual

Page: 14 / 40

14
6. Code Deviation Check
Setting:
Procedure:
1. Connect a deviation meter to TP (ANT) and TP (GND) on the
HAND MAIN board.
2. Press the
[3]
key to change the test mode step to TX DATA.
3. Check that the value of deviation meter is 6 kHz to 10 kHz.
– RX Adjustments and Checks –
1. DISCRI Voltage Adjustment
Setting:
Procedure:
1. Connect a SSG to TP (ANT) and TP (GND) on the HAND
MAIN board.
2. Connect a digital voltmeter to TP (DISCRI) and TP (GND) on
the HAND MAIN board.
3. Press the
[4]
key to change the test mode step to RX SENS.
4. Adjust L402 on the HAND MAIN board so that the value of
digital voltmeter becomes 1 V
±
0.05 V.
2. Speaker Out Level Adjustment
Setting:
Procedure:
1. Change the modulation of SSG to 1 kHz,
±
8 kHz deviation.
2. Disconnect the speaker (SP801).
3. Connect a noise meter to TP (SP+) and TP (SP–) on the HAND
MAIN board.
+
–
deviation meter
TP (ANT)
TP (GND)
SSG
Carrier frequency: 926.997467 MHz
Modulation: no modulation
Output level: – 47 dBm
TP (ANT)
TP (GND)
+
–
digital voltmeter
TP (DISCRI)
TP (GND)
SSG
Carrier frequency: 926.997467 MHz
Modulation: 1 kHz,
±
8 kHz deviation
Output level: – 47 dBm
TP (ANT)
TP (GND)
TP (SP+)
TP (SP–)
150
Ω
noise meter
+
–
4. Set the
[VOL]
switch (S401) to
[M]
position.
5. Adjust RT402 on the HAND MAIN board so that the value of
noise meter becomes 115 mV
±
10 mV.
3. Distortion and S/N Ratio Check
Setting:
Procedure:
1. Connect a distortion meter to TP (SP+) and TP (SP–) on the
HAND MAIN board.
2. Check that the value of distortion meter is less than 4%.
3. Check that the value of noise meter, and record it.
4. Change the modulation of SSG to no modulation.
5. Check that the value of noise meter again. And check that dif-
ference of level between in step3 and in step5 is more than
60 dB.
4. RX Sensitivity Check
Setting:
Procedure:
1. Change the output level of SSG to –111 dBm.
2. Connect a SINAD meter to TP (SP+) and TP (SP–) on the
HAND MAIN board.
3. Check that the value of SINAD meter is more than 12 dB.
SSG
Carrier frequency: 926.997467 MHz
Modulation: 1 kHz,
±
8 kHz deviation
Output level: – 47 dBm
TP (ANT)
TP (GND)
TP (SP+)
TP (SP–)
150
Ω
noise meter
CCITT: on
+
–
+
–
distortion meter
SSG
Carrier frequency: 926.997467 MHz
Modulation: 1 kHz,
±
8 kHz deviation
Output level: –111 dBm
TP (ANT)
TP (GND)
150
Ω
+
–
SINAD meter
TP (SP+)
TP (SP–)