75

A/V Processing
There are three major ICs in the combined A/V processing chain; two
buffers in the following video chain and nine ICs in the final audio chain:
A/V Processing ICs
Combined A/V Video Audio
RF Amp IC001 Video Buffers IC303 DSP IC501
ARP2 IC303 Video Buffers IC321 2Ch D/A Conv. IC902
A/V Decoder Front Ch D/A Conv. IC902
Rear Ch D/A Conv. IC902
Center/Woofer D/A
Converter IC907
Amplifiers IC431, IC502,
IC541 and IC571
Once the servos begin operation, there is RF output from the optical de-
vice in the base unit. These ICs process the RF output:

RF Amp IC001

Purpose:
Amplifies and matrixes the A-D input signals from the optical assembly to
produce RF, FE, PI outputs. Matrixes the E-H input signals to produce
TE (and TZC).
Outputs:
·RF signal for A/V and spindle motor processing
·FE,TE, PI signals for servo control

ARP2 IC303

Purpose:
·Asymmetrical correction – Active circuit for AC coupling the input RF
signal. Shapes sine input signal into a square wave.
·Sync clock extraction – Bit clock (PLL) made from the disc data.
·EFM and De-Interleaving – First level of descrambling the data pieces
using external memory IC304 (Reed – Solomon Code).
Outputs:
DVD Output Signals from IC303
Name From IC Purpose When present
SD 0-7
disc
data
IC303/pins
97, 98, 100-
105.
A/V disc data DVD PB only
XSHD IC303/pin 93 0.25usec low going pulse
to mark the beginning of
the DVD data
DVD PB only
XSRQ IC401/pin 51 Used as a busy line DVD PB only
XSAK IC303/pin 95 Data Acknowledgement DVD PB only
SDCK IC303/pin 91 Bit clock Power on
CD Output Signals from IC303
Name From IC303 Purpose When present
Data Pin 107 CD data Power on
D Out (data) Pin 110 CD data CD PB only
B Clk Pin 108 Bit clock Power on
L/R Clock Pin 109 Left/right clock Power on
The following waveforms show the two CD data outputs (Ch 1 and Ch 3)
from ARP2 IC303 accompanied by the left / right clock (Ch 2).
PM3394, FLUKE & PHILIPS
ch3
ch2
ch1 ch1: freq= 927kHz
CH1!5.00 V=
CH2!5.00 V=
CH3!5.00 V= ALT MTB2.00us- 2.00dv ch1+
1
2
3
T
CD Data Output Waveforms – CD PB
Name Location Voltage/div
Channel 1 CD Data IC303/pin 107 5Vp-p
Channel 2 L/R Clock IC303/pin 109 5Vp-p
Channel 3 CD D O ut (data) IC303/pin 110 5Vp-p
Time base 2usec/div.