Hitachi DV-P303U Service Manual page 55

Circuit Descriptions
6-2 RF
6-2-1 RIC1 (KS1461)
KS1461 is combined with KS1452 and KS1453 as bipolar IC developed for DVD SERVO system.
Main features include DVD waveform equalizing, CD waveform equalizing, focus error signal generation, 3-beam
tracking error signal generation, DPD 1-beam tracking error, defect, envelope, MIRR output, etc. after receiving the
pick-up output converted into I/V.
6-2-1 (a) Basic Potentiometer
KS1461 uses a single power method and each circuit is based on V of 2.5V.
V (Pin 12, 20, 24, 67) terminal is needed for IC, which uses the peripheral V.
6-2-1(b) RF signal
Fig. 6-11 shows the flow of signal generated by the pick-up.
A, B, C, D signals detected from pick-up are converted in to RF signal(A+B+C+D) via RF summing AMP.
PICK-UP
PD LD F E
Fig. 6-12 shows the waveform-equalizing block diagram for the RF signal.
It outputs to EQout (Pin 86) terminal by initially changing switching AMP gain of DVD and CD, and then
adjusting the level in RF SUM & AGC. It controls RF SUM & AGC gain by means of Pin 89-95 and interfaces with
PWM signal, (output from PWM terminal of KS1453, via low-pass filter to adjust boost gain and peak frequency.
6-6
104
A
5
104
B
6
104
C
7
104
D
8
13
TE
14
15
16
17
18
28
29
104
474
RFAGCO
89 88
RE SUM
& AGC
DPD
TE
ABCD
SUM
FE
ALPC
Fig. 6-11
MIRRI
EQIN
84
MIRR MIRR
57
,
86
RF EG
TESEL
Mhx
36 TE
ABCDI
40
39
ENV
ENV
43
FOKB
46
FOK
DFCT2
55
DEFECT DFCT1
54
FE
33
RFEQO
103
ABCD