Philips 32PF9968/10 Service Manual page 76

EN 76 9. LC4.8L LA
The PLL tuner UV1316E/1318SD/TEDE9 delivers the IF-
signal, via audio & video SAW-filters, to the Video Signal
Processor and FLASH embedded TEXT/Control/Graphics
Micro Controller 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 three external CVBS inputs and a CVBS
output. All CVBS inputs can be used as Y-input for Y/C signals.
However, only two Y/C sources can be selected because the
circuit has two 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. There are two rear
analogue video inputs: AV is for SVHS in and video (CVBS) in,
and CVI-1 is meant for RGB/YUV in). The rear VIDEO OUT
cinch connector can be used for monitoring purposes:
WYSIWYR (What you see is what you record).
Depending on the model of the TV set, the Hercules delivers its
RGB signals either directly to the Scaler IC or indirectly, via a
Columbus chip (for 2D/3D comb filtering and spatial/temporal
noise reduction, for its description: see further down in this
text). The EPLD, which is present in the Pixel Plus models
discussed in this manual, provides additional sharpening to the
picture. For a general outline, see the table and the block
diagrams below, in which the architectures of the various
models are given, together with their electronic building blocks.
Table 9-1 Models and picture quality
Model
42PF7312/77, /78
37PF7312/77, /78
32PF5312/77, /78
CVBS
Pb, Pr
PIXEL PLUS HERCULES ADC
CVBS
Pb, Pr
DIGITAL
HERCULES ADC
CRYSTAL CLEAR
R, G, B
CRYSTAL CLEAR HERCULES
Figure 9-2 Block diagram of the internal building blocks
The Genesis GM1501 Malibu Scaler IC can receive the
following video input signals: SDTV (directly from Hercules or
via Columbus), DVI (from an external DVI source), or PC (from
external computer).
After the video processing, the digital data is sent via a Low
Voltage Differential Signalling bus to the LCD panel. LVDS is
used to improve data speed and to reduce EMI significantly.
2
There are two I 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.
Circuit Descriptions, Abbreviation List, and IC Data Sheets
Picture quality
Pixel Plus
Pixel Plus
Digital Crystal Clear
COLUMBUS SCALER EPLD LVDS
COLUMBUS SCALER LVDS
SCALER LVDS
F_15270_008.eps
240505
The Hercules, and EEPROM are supplied with 3.3 V, which is
also present during STANDBY.
The EEPROM, or NVM (Non Volatile Memory) is 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 Input/Output
The I/O is divided over two parts: Rear I/O and Side I/O. The
rear has two AV inputs with CVBS, Y/C and YUV, a PC (VGA)
input, and an HDMI input. The side has a CVBS and Y/C
(SVHS) input.
The selection of the external I/O's is controlled by the Hercules.
AV1 / CVI-1: The input of AV1 / CVI-1 is CVBS + YUV + L/R.
AV2: The input of AV2 is Y/C + CVBS + L/R.
PC-VGA/CVI-2: This input is directly going to the Scaler IC.
See paragraph "Video: Scaler Part".
HDMI in / PC-D: This input is directly going to the Scaler IC.
See paragraph "Video: Scaler Part".
9.4 Tuner and IF
The VIF/SIF signals are decoded by the Hercules. Tuning is
2
done via I C.
9.4.1 Video IF Amplifier
The IF-filter is integrated in a SAW (Surface Acoustic Wave)
filter. One for filtering IF-video (item 1104, in some models:
1105) and one for IF-audio (item 1106). For LATAM however,
one combined filter is used for filtering IF-video and audio (item
1104). The type of the SAW filter depends on the standard(s)
that has(have) 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.