Samsung MAX-870, Service Manual

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Special Circuit Descriptions
Samsung Electronics 5-5
5-1-9 AGC Stability Circuit
5-1-10 Post Filter
5-1-11 Center Voltage Generation Circuit
The gain is adjusted by AGC Block with the function of maintainning the definite RF peak to peak level,
after the operation of RF envelop detection and comparing with reference voltage.
RFO level is kept stable in 1Vp-p, and input to EFM Slice.
The adjustment of audio output gain and the integration of possible de-emphasis output are executed by
the low pass filter. If the control by MUTE signal from micom exist, and when input signal absent, two
channel of right and left is builted in.
The Center Voltage is generated by using resistor dividing voltage.
75 78
76
IRF CAGC
ARF
EQUALIZE VCA
25K
CH2O
GC2O
GC1O
CH1O
25K
CH2I
GC2I
GC1I
GC1I
MUTEI (From Micom)
+
-
+
-
+
-
+
-
+
-
12
10
15
13
19
30K
VC
30K
+
-