Outline; Circuit Configuration; Video Signal Demodulation Block; Rgb Signal Amplification Circuit Block - Toshiba TLP411E Technical Training Manual

1. OUTLINE

1-1. Circuit Configuration

The video signal process circuit consists of a video signal
demodulation (NTSC, PAL, SECAM), RGB signal (VGA,
SVGA) amplification and audio signal amplification cir-
cuits. Fig. 7-1 shows the block diagram.

1-2. Video Signal Demodulation Block

The video signal demodulation block demodulates the com-
posite video signal and YC signal into the RGB signals.
The composite video signal is separated into a luminance
signal (Y) and a color signal (C) in passing through a digi-
tal comb filter.
The YC signals selected by the input SW IC are processed
in the Video/Color process IC and color difference signal
delay circuits, and a Y color difference signal is created. At
the same time the Y signal is corrected in its picture sharp-
ness by the sharpness correction circuit and then fed to the
RGB demodulation IC. The RGB demodulation IC devel-
ops R, G, and B signals.
AVINPUT PC Board
AUDIO OUT
L
BUFFER
R
Q201
VIDEO OUT
TA9090AN
BUFFER
Q200
VIDEO
AUDIO L
AUDIO R
A/V SW
S-Y
TA1218N
S-C
RGB
AUDIO L
AUDIO R
RGB IN
R
G BUFFER
B
HD
BUFFER
VD
RGB OUT
HD
BUFFER
VD
R
BUFFER
G
B
DIGITAL PC Board
Q221
Y/C SEP DELAY
BUFFER
TDA4665T
Y C
fsc
Q220
Y
VIDEO & COLOR
TDA9141
C
Q224
Y
C
HD
VD
Q537
CAMERA-Y
CAMERA-C
Fig. 7-1 Block diagram
1-3. RGB Signal Amplification Circuit
Block
The RGB input signals are gain-adjusted in passing through
the RGB process IC after the signals are switched to the
RGB demodulated video signal, and then the RGB input
signals are fed to the drive circuit provided in a later stage
through the switching circuits.
The sync signal is corresponding to HD, VD, composite
sync (CS) and SYNC ON G signals. The sync signal en-
tered is separated into a HD and VD and waveform-shaped
in the sync separation IC.

1-4. Audio Signal Amplification Block

Audio signal inputs are corresponding to L and R stereo
inputs on the video and RGB inputs. The signals are output
to the audio signal output terminals through the input SW
IC. At the same time, the L and R signals are mixed, level
adjusted in the volume control IC, and amplified by the
audio output IC to a sufficient level to drive the speaker.
AUDIO PC Board
QA03
VOL MUTE
&
M5222F
Q222
PSI
TDA4672
Y
Q223
R
sc Y
R-Y
RGB DECODE
G
DL
TDA4780
B-Y
B
DL
HD VD
SW
MC14053BF
HD VD
SYNC SEP
M52346SP
From camera block
From Microcomputer
7-2
QA04
AUDIO OUT
TDA7056A
DIGITAL
PROCESS
HD
VD
R G B OSD
Q535
Q530 R
SW
RGB
Q525 G
SW PROCESS
M52320SP
Q520
B
SW
PD74HC4066x3
Q540
2
I C DAC
CXA1315M
SP
R
G
B