Video Output Circuit (Rjk Substrate); Audio Circuit - Hitachi DV-P250E Bedienungsanleitung

VIDEO OUTPUT CIRCUIT (RJK substrate)

Analog composite video signals (CVBS), analog intensity signals (Y), analog chroma signals (C) and analog
component signals (YP
connector (PG2201~CN1302). From RJK substrate, CVBS signals are output from output terminal J1307 and
Y/C signals are output from output terminal J1302. Component signals are output from output terminal J1306
(YP P ) or J1361 (RGB).
B R

AUDIO CIRCUIT

Audio circuit is shown in page 15.
Audio circuit is composed of D/A converter sector (DEC substrate) that transforms digital audio signals output from
A/V decoder (IC1201), analog processing sector (RJK substrate) that consists of an operational amplifier, and mute
circuit (DEC substrate, RJK substrate) for stopping audio output when required.
1. D/A CONVERTER SECTOR (DEC substrate)
D/A converter sector is composed of IC1502 that receives and transforms digital audio signals from A/V
decoder in analog signals.
IC1502 is a converter corresponding to FL and FR signals of sampling frequencies 44.1/48/96KHz and
data lengths16/20/24bit, and digital audio signals from A/V decoder is input at pin 2.
To these digital audio signals are inserted FL and FR signals in time sharing mode. When they are input in
pin 1, they are separated in FL and FR signals by R clock and after transformation analog FL signals are
output at pin 16 and FR signals at pin 13. Moreover, when there are no input signals at pin 2, a signal
called ZERO MUTE is output to pin 21 to mute useless noises (See paragraph on MUTE CIRCUIT.)
Every functions of IC1502 is preset by MICOM and controlling signals from SH MICOM are input at pins
26, 27,and 28. As for presetting items, there are data length, sampling frequency, signal polarity, and de-
emphasis.
2. ANALOG PROCESSING SECTOR (RJK substrate)
Analog processing sector is composed of operational amplifier IC1508 that is a filter and operational
amplifier IC1510 that amplifies audio signals.
Filter portion is composed of RC low pass filter and IC1508 formed active low pass filter and there are 3
sections. The diagram below shows its filter portion circuit (for FL signals only).
Chapter 1
P are sent from DEC substrate to RJK substrate by passing through 17P
B R/RGB)
DEC Substrate RJK Substrate
PG2201 PG1302
J1307
VIDEO
J1302
J1361
SCART
J1306
COMPONENT
S
13