Sony CDX-C680 Service Manual page 28

Ver 1.1
FM Stereo Separation Adjustment (WIDE)
Setting :
SOURCE button : FM
FM RF signal
generator
0.01 µF
Carrier frequency : 97.9 MHz
Output level : 70 dB (3.2 mV)
Mode : stereo
Modulation : main : 1 kHz, 33.75 kHz deviation (45%)
sub : 1 kHz, 33.75 kHz deviation (45%)
19 kHz pilot : 7.5 kHz deviation (10%)
Procedure :
1. Set to the test mode.
2. Push the SHIFT button.
3. Push the 4 button three times.
4. Push the 5 button once and set to WIDE mode.
FM stereo
Level meter
signal generator
connection
output channel
L-CH L-CH
R-CH L-CH
R-CH R-CH
L-CH R-CH
L-CH stereo separation : A – B
R-CH stereo separation : C – D
The separations of both channels should be equal.
Specification : Separation more than 24 dB
Adjustment Location : See page 29.
level meter
antenna
terminal 10 k Ω
set
LINE OUT REAR
Level meter
reading (dB)
A
B
Adjust RV3 on TU10 for
minimum reading.
C
D
Adjust RV3 on TU10 for
minimum reading.
FM Stereo Separation Adjustment (NARROW)
Setting :
SOURCE button : FM
FM RF signal
generator
0.01 µF
Carrier frequency : 97.9 MHz
Output level : 70 dB (3.2 mV)
Mode : stereo
Modulation : main : 1 kHz, 33.75 kHz deviation (45%)
sub : 1 kHz, 33.75 kHz deviation (45%)
19 kHz pilot : 7.5 kHz deviation (10%)
Procedure :
1. Set to the test mode.
2. Push the SHIFT button.
3. Push the 4 button three times.
4. Push the 5 button twice and set to NARROW mode.
FM stereo
signal generator
output channel
L-CH
R-CH
R-CH
L-CH
L-CH stereo separation : A – B
R-CH stereo separation : C – D
The separations of both channels should be equal.
Specification : Separation more than 18 dB
Adjustment Location : See page 29.
– 28 –
antenna
terminal 10 k Ω
set
LINE OUT REAR
Level meter Level meter
connection reading (dB)
L-CH A
B
L-CH Adjust RV4 on TU10 for
minimum reading.
R-CH
C
D
R-CH Adjust RV4 on TU10 for
minimum reading.
level meter