2
CX-958
1. CIRCUIT DESCRIPTIONS
The LSI (UPD63711GC) used on this unit comprises six main blocks ; the pre-amp section, servo, signal processor,
DAC, CD text decoder (not used on this model) and LPF. It also equips with nine automatic adjustment functions.
1.1 PRE-AMP SECTION
This section processes the pickup output signals to
create the signals for the servo, demodulator and
control.
The pickup output signals are I-V converted by the pre-
amp with the built-in photo-detector in the pickup, then
added by the RF amp to obtain RF, FE, TE, TE zero cross
and other signals.
This pre-amp section is built in the servo LSI
UPD63711GC (IC201). The following describes function
of each section.
Since this system has a single power supply (
+
5V), the
reference voltage for this LSI and pickup are set to
REFO (2.5V). The REFO is obtained by passing the
REFOUT from the LSI through the buffer amplifier. The
REFO is output from Pin 89 of this LSI. All
measurements are done using this REFO as reference.
Note : During the measurement, do not try to short the
REFO and GND.
1) APC Circuit (Automatic Power Control)
When the laser diode is driven with constant current,
the optical output has large negative temperature
characteristics. Thus, the current must be controlled
from the monitor diode so that the output may be
constant. APC circuit is for it. The LD current is obtained
by measuring the voltage between LD1 and V
+
5. The
value of this current is about 35mA.
71
72
74
76
AGCI
77
RFO
75
78
79
80
73
91
90
93
92
C-3T
FEO
FE-
TEO
TE-
85
86
87
E
97
PD
99
PN
F
D
82
83
84
B
C
A
RF-
EQ1
EQ2
AGCO
RFI
ASY
EFM
PEAK DET.
LPF
BOTTOM DET.
S/H
D/A
A/D
D/A
A/D
94
98
TE2
LD
VREG
GND
APN
LDON
EFM
DEFECT
FOK
A3T
MIRR
To the
following stage
of the LSI
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
·····Vref(+2.5V)
97
PD
99
PN
98
LD
VREG
GND
AMP_PN
(H:Nch L:Pch)
LDON
(H:LD MOVE L:STOP)
Vref
·····Vref(+2.5V)
14
5
R102
10
R101
12
Q101
2SB1132
C102
0.1
µ
F
C103
100
µ
F/6.3V
PU UNIT
R103
2.2k
C105
0.33
µ
F
+
5V
1k
110k
3p
3p
150k
100k
100k
16k
1k
Fig.1 : BLOCK DIAGRAM OF BUILT-IN RF AMPLIFIER
Fig.2 : APC CIRCUIT
Содержание DEH-1350B
Страница 6: ...4 DEH 2350 1350 2 2 EXTERIOR B A ...
Страница 8: ...6 DEH 2350 1350 2 3 CD MECHANISM MODULE C D ...
Страница 25: ...23 DEH 2350 1350 ...
Страница 27: ...25 DEH 2350 1350 5 6 7 8 5 6 7 8 D C B A A FRONT 1 2 3 1 2 FM AM TUNER UNIT SIDE A ANTENNA PRE OUT ...
Страница 28: ...26 DEH 2350 1350 1 2 3 4 1 2 3 4 D C B A A 4 5 6 3 2 1 1 2 3 6 5 4 A TUNER AMP UNIT ...
Страница 29: ...27 DEH 2350 1350 5 6 7 8 5 6 7 8 D C B A A 1 2 3 6 5 4 4 5 6 3 2 1 FRONT SIDE B ...
Страница 31: ...29 DEH 2350 1350 1 2 3 4 1 2 3 4 D C B A B B CN601 A SIDE B KEYBOARD UNIT ...
Страница 33: ...31 DEH 2350 1350 1 2 3 4 1 2 3 4 D C B A CLAMP SIDE B CONTROL UNIT C C ...
Страница 40: ...38 DEH 2350 1350 Grating waveform Ech Xch 20mV div AC Fch Ych 20mV div AC 45 0 75 60 30 90 ...