Pioneer CX-3195 Manuale di servizio - Pagina 5

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5
1.1.2 RF and RFAGC amplifiers
The output from the photo-detector (A + C) and (B + D) is provided from the RFO terminal as the RF signal (which can be
used for eye-pattern check), after it is added, amplified, and equalized inside this LSI. The low frequency component of the
voltage RFO is calculated as below.
RFO = (A + B + C + D) x 2
The RFO is used for the FOK generation circuit and RF offset adjustment circuit.
The RFO signal, output from the pin 122, is A/C-coupled externally, input to the pin 121, and amplified in the RFAGC
amplifier to obtain the RFAGC signal.
Also, this LSI is equipped with the RFAGC auto-adjustment function, explained below, which switches feedback gains of
the RFAGC amplifier so that the RFO output will be 1.5 V.
This RFO signal is also used for the EFM, DFCT, MIRR, and RFAGC auto-adjustment circuits.
Pickup Unit
P3
P7
A+C
13
P9
VREF
P2
P4
B+C
6
P8
Fig.1.1.2 RF/AGC/FE
5
6
CD CORE UNIT
PE5547A
15.2k
15.2k
VREF
R2
+
61.0k
-
A
13
129
10k
8.8k
61.0k
+
-
B
6
130
10k
8.8k
6
7
3.55k
+
+
-
-
44k
11.75k
20k
RFOFF setup
+
-
140k
FEOFF setup
VREF
CX-3195
7
8
RF-
126
RF2-
4.7k
125
22p
1.2k
EQ2
123
4p
56p
1.2k
5k
5k
124
EQ1
5.6k
-
119
+
AGCO
To DEFECT/A3T detection
For RFOK generation
+
FEO
135
-
FE A/D
160k
FE-
134
8
A
B
C
D
E
F
5