Philips 28PW9618, Руководство по обслуживанию

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Circuit Descriptions, Abbreviation List, and IC Data Sheets
EN 137 EM6E 9.
9.5
Input/Output (I/O)
Table 9-1 Overview of inputs
9.6
Video
9.6.1
Tuner & IF
Note: The "Tuner & IF" parts for the main picture and the DW/
PIP picture are comparable.
The tuner/splitter is I2C controlled, and is capable of receiving
off-air and cable channels.
Also, the tuning is done via I2C. The reference voltage on pin
9 is 33 V. This voltage (+33V) is derived from the secondary
side of the standby supply (V_TUN), via D6110 and R3116//
R3115 and a 33 V zener diode. The OTC, together with the
HIP, controls the tuning procedure. There is also automatic
switching for the different video systems.
The IF-filter is integrated in a SAW (Surface Acoustic Wave)
filter. The type of this filter depends on the received
standard(s). There are two SAW filters: one for filtering picture-
IF and a second one for sound-IF.
The output of the tuner is controlled via an IF-amplifier with
AGC-control. This is a voltage feedback from pin 62 of the HIP
to pin 1 of the tuner. AGC take-over point is adjusted via the
service alignment mode "Tuner AGC". If there is too much
noise in the picture, it is possible that the AGC setting is wrong.
It is also possible that the AGC-setting is misaligned, if the
picture deforms with a perfect signal. Then the IF-circuit is
amplifying too much.
The video IF-signal is fed to pins 2/3 of the PLL-controlled IF-
demodulator. The voltage-controlled oscillator of the PLL is
adjusted via the service menu "IF AFC". If the alignment is
correct, the displayed frequency in the installation menu is the
same as the applied frequency from a generator. The external
coil L5408 (or L5P08 for the DW/PIP circuitry), connected
between pins 7/8, is used as reference.
The demodulated IF-video signal is available at pin 10 of the
HIP. In this video signal, there is a rest of the sound carrier,
which is filtered out by the sound trap 1407 (or 1P09 for DW/
PIP).
Then the signal is fed again to the HIP on pin 12, where the
group delay is corrected, dependent on the standard that is
received.
The CVBS-signal is available at pin 13 for further processing in
the set. Via TS7322, the signal is supplied to EXT1 (SCART pin
19, CVBS out) and again back into the HIP (pin 14) to the
source/record selection.
To achieve Quasi Split Sound (QSS), the IF-signal is fed to the
HIP on pin 63/64 via SAW-filter 1409 (or 1P04 for DW/PIP).
The FM-modulated signal is available on pin 5 and is fed to the
audio demodulator (item 7A02).
9.6.2
Video: DW/PIP (diagram B15)
Introduction
The Double Window (DW) panel provides the option for the
viewer to see two (or more) pictures / programs on the
displayed area of a TV screen. The displayed pictures can be
in PIP mode or DW mode. The viewer can also select the size
and position of the "second" picture.
New DW/PIP features with respect to 2002:
•
Making use of HIP instead of BOCMA.
•
Provisions to use 2D Comb filter for the sub-picture.
•
New modes by making use of FBX (e.g. Multi-PIP 12, Multi-
PIP 9, Multi-PIP 8 surround).
•
Photo finish in correct order by making use of FBX.
IF and Video section
The "IF and video" processing in the DW module is performed
by a HIP IC, same as for the main picture.
Processing
The MUPPET IC (SAB9081, item 7PA6) is a multi-standard
PIP controller, which can be used in Double Window or PIP
applications.
The main picture YUV is fed to pins 98, 2, and 100, while the
sub picture YUV is fed to pins 83, 79, and 81.
These signals are mainly used during the DW mode. In PIP
mode, the signals are inserted into the main picture with
reduced size.
Inside the MUPPET, the conversion to the digital environment
is done with ADCs. Processing and storage (1 MB DRAM) of
the video data is done entirely in the digital domain. The
conversion back to the analogue domain is done by DACs.
Internal clocks are generated by PLLs, which lock on to the
applied horizontal and vertical syncs from the main and sub
pictures. The main picture syncs are applied to pin 70 (V) and
pin 94 (H) and the sub picture syncs are applied to pin 72 (V)
and pin 87 (H).
For DW mode, the main picture is compressed horizontally by
a factor of two and fed directly to the output. After compression,
a horizontal expansion of two is possible for the main picture.
The sub picture is also compressed horizontally by a factor of
two but stored in memory before it is fed to the outputs.
Name Type Capabilities
CVBS-in RGB-in (1fH) Y/C-in Status 4:3
or 16:9 P50 Analog Audio-in Digital Audio-in
EXT1 SCART X X X X
EXT2 SCART X X X X X X
EXT3 SCART X X X
EXT4 SCART X X X
Side Cinch X X
SVHS X X
S/PDIF Cinch X
S/PDIF Cinch X
Center Cinch X