Circuit Descriptions, Abbreviation List, and IC Data Sheets
9.
The PLL tuner delivers the IF-signal, via audio & video SAW-
filters, to the Video Signal Processor with FLASH embedded
TEXT/Control/Graphics m-Controller (TCG m-Controller) and
US Closed Caption decoder. TDA120x1 (item 7011, also called
Hercules). This IC has the following functions:
•
Analogue Video Processing.
•
Sound Demodulation.
•
Audio Interfaces and switching.
•
Volume and tone control for loudspeakers.
•
Reflection and delay for loudspeaker channels.
•
Micro Controller.
•
Data Capture.
•
Display.
The Hercules has one input for the internal CVBS signal and a
video switch with 3 external CVBS inputs and a CVBS output.
All CVBS inputs can be used as Y-input for Y/C signals.
However, only 2 Y/C sources can be selected because the
circuit has 2 chroma inputs. It is possible to add an additional
CVBS(Y)/C input (CVBS/YX and CX) when the YUV interface
and the RGB/YPRPB input are not needed. The I/O is divided
over two parts: Rear I/O and Side I/O. The rear has two SCART
inputs and a PC (VGA) input. The side has a CVBS and Y/C
(SVHS) input.
The video part delivers the RGB signals to the Scaler IC.
The Genesis GM1501 Malibu Scaler IC can receive different
video input signals: SDTV (from Hercules) or PC (VGA) (from
external computer).
After the video processing, the digital data is send via a Low
Voltage Differential Signalling bus to the display panel. LVDS
is used to improve data speed and to reduce EMI significantly.
There are two I
2
C lines and two interrupt and communication
lines (TV_IRQ and TV_SC_COM) for the Scaler control. The
Scaler communicates with the Hercules as a slave device. To
avoid buffer overflow at the Scaler side, the TV_SC_COM line
provides the necessary hardware flow control. To allow bi-
directional communication, the Scaler can initiate a service
interrupt-request to the Hercules via the TV_IRQ line.
The Hercules, and EEPROM are supplied with 3.3 V, which is
also present during STANDBY.
The EEPROMs, or NVMs (Non Volatile Memory) are used to
store the settings.
The sound part is built up around the Hercules. The Source
Selection, Decoding and Processing are all done by the
Hercules.
Power supply input are several DC voltages coming from a
supply panel.
9.3
Power Supply (SDI plasma panel)
See the FTP1.1 manual for a more detailed description.
9.3.1
Start-up sequence
Figure 9-2 Start-up sequence SDI plasma panel
9.4
Input/Output
The I/O is divided over two parts: Rear I/O and Side I/O. The
rear has two SCART inputs, a PC (VGA) input, and an Audio
input. The side has a CVBS and Y/C (SVHS) input.
EXT1: The input of SCART1 is CVBS + RGB + L/R and the
output is the video (+ sound) signal from the tuner
(SC1_CVBS_RF_OUT).
EXT2: The input of SCART2 is Y/C + CVBS + L/R. The output
signal is CVBS_SC2_MON_OUT (+ sound).
SCART2 is meant for VCR and has therefore some additional
signals in relation to EXT1 but no RGB: it has the possibility for
Y/C_in: Y_in on pin 20 and Chroma_in on pin 15.
The selection of the external I/O's is controlled by the Hercules.
PC (VGA) in: This input is directly going to the Scaler IC. See
paragraph “Video: Scaler Part”.
9.5
Tuner and IF
A Philips UV13xx Tuner is used in the TV board. The SIF
signals are decoded by the Hercules. Tuning is done via I
2
C.
9.5.1
Video IF amplifier
The IF-filter is integrated in a SAW (Surface Acoustic Wave)
filter. One for filtering IF-video (1328) and one for IF-audio
(1330). The type of these filters is depending of the standard(s)
that has to be received.
The output of the tuner is controlled via an IF-amplifier with
AGC-control. This is a voltage feedback from pin 31 of the
Hercules to pin 1 of the tuner. The AGC-detector operates on
top sync and top white level. AGC take-over point is adjusted
via the service alignment mode "Tuner” - “AGC". If there is too
much noise in the picture, then it could be that the AGC setting
is wrong. The AGC-setting could also be mis-aligned if the
picture deforms with perfect signal; the IF-amplifier amplifies
too much.
AC Inp
u
t
9
V
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b
y
5
V
2
5
V
_relay_Io2
STA
N
DBY
5
V
_S
W
,
8V
6,
12
V
,
V
TU
N
,
V
S
N
D
3
V
3, 5
V
V
a,
V
g
V
s_on
(LOGIC BD)
A
b
o
u
t 1.4s
8
00ms
Po
w
er_Se
qu
ence
(LOGIC BD)
V
s,
V
scan
V
e,
V
set
Po
w
er_OK
(PSU)
Image data
Pl
u
g-o
u
t
Remote On
Remote On
S/
W
On
Pl
u
g-in
Remote Off
E_14720_016.eps
260
8
04
8
00ms
