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Circuit Descriptions, List of Abbreviations, and IC Data Sheets
9.4.2
SSP: Tuner and IF
1
5103
1102
11
SPLITTER
TUNER
40,4
+8V6
TO DW TUNER
7111
1106
5.5MHz
BG/BG
+
7502
3560
CVBS-TER
+5V
3109
6102
Figure 9-11 Overview Tuner and IF Part
Normally for chassis with the Double Window feature, a splitter
is used. This splitter is on the chassis, beside the main tuner.
From this splitter, the aerial signal is fed to the main tuner on
the SSP and the DW tuner on the DW panel (which is not
present in this chassis). Therefore, the aerial input is on the
splitter.
The tuner part contains a tuner and an oscillator-mixer. The
tuner is I2C controlled. The reference voltage at pin 9 is 33 V.
This voltage (V_TUN) is derived from the secondary side of the
standby supply. The OTC, together with the HIP, controls the
tuning procedure.
The frequency of the local oscillator is compared with the
frequency of a reference oscillator by a PLL. The varicap
voltage is changed via I2C, and that changes the frequency of
the reference oscillator.
For the higher frequencies, the tuning speed is increased by
increasing the current that changes the varicap voltage.
The IF-part can be split into two important parts:
1. The IF-filter.
2. The IF-amplifier and demodulator.
The IF signal is fed to a SAW filter (item 1109 for the video and
1104 for the audio). The output of this filter is fed to the HIP for
demodulation. The demodulator is PLL-controlled via a VCO.
This VCO is I2C controlled (Service Alignment Mode IF-AFC
alignment). Tuning of the VCO is possible by switching some
small capacitors parallel to L5108. These capacitors are
integrated in the HIP.
In addition, the AGC takeover point is I2C controlled (with the
SAM menu).
Service tip: If the AFC is not adjusted correctly, very strange
faults can occur: like spontaneous standby switching, cracking
sound, incorrect CC, etc.
L5108
AGC TUNER
1109
7501
62
7
3
SAW
FILTER VIDEO
2
VIF
DEMOD
10
HIP
TDA9320H
12
DELAY
OPTIM BG
OR
FLAT
13
14
PLUG
EXT1
VIDEO
EXT2
SWITCH
SOURCE
EXT3
SELECT
EXT4
FRONT
1104
63
SAW
SIF
FILTER SOUND
64
5
AM SOUND
SIF MSP
CL 06532023_046.eps
The demodulated video signal is available at pin 10, and then
fed to a sound-trap. This is for filtering the rest sound carrier.
Then the group delay time (system dependent) can be
adapted, and at pin 13 of the HIP, the CBVS is available for
further processing in the set.
8
The tuner-IF signal is also fed to a second SAW filter for the
sound. At pin 5 of the HIP, the IF-sound is available. This signal
is fed to the MSP for further processing (the IF-sound is
demodulated by the MSP3410).
9.4.3
SSP: HIP (High-end Input Processor, diagram K1)
Introduction
The HIP (IC7501, TDA9320H) has the next functions:
•
Source selection.
•
Video IF-demodulation.
•
Luminance, chrominance, and sync processing.
Inputs
The set has a total of five external inputs (AV1 - 5).
The HIP has an integrated source selector, which can handle:
•
3 CVBS inputs.
•
2 Y/C inputs.
•
2 RGB inputs.
The HIP detects whether the input is Y/C or CVBS and decides
what to do. There are two inputs (pins 39 and 40) for detection
of the RGB status. The other status voltages are checked by
the OTC.
Video Processing
•
The video identification block monitors whether a video
240901
signal is detected at one of the inputs. The Y/C switch
detects whether the input is CVBS or Y/C, and switches
these signals for luminance and chrominance processing.
If a comb filter is used, the HIP detects they are "combed",
and the YC switch will select the signals for the comb filter.
The comb filter can be switched to the right system via the
two system lines (SYS1 and SYS2) from the HIP.
•
If the input signal is CVBS, then an internal colour trap is
used in the Y path.
•
The Y-delay can be controlled via the service menu to
match the colour to the luminance (because of different
signal paths there are different timings)
•
Via the RGB-matrix, external RGB-signals are converted to
YUV, for further 2fH conversion.
•
The internal YUV switch switches between the
demodulated video signal and an external RGB source.
•
The sync processor in the HIP provides H_A and V_A sync
signals for the Feature Box. This sync part is alignment
free, but it should be noted that the line oscillator is locked
with the colour oscillator.
Note: If the quartz crystal is defective, there will be no colour
and synchronization problems. This crystal is very precise: if it
is replaced by another type, there may be no colour, because
of a different capacity. Therefore, you must use the genuine
replacement part.
Outputs
The HIP has the following outputs:
•
YUV (50 Hz), for further picture processing on pins 49, 50
and 51.
•
CVBS-DW, video signal for the Double Window module (if
present) on pin 32.
•
CVBS-SC2-OUT, monitor output (WYSIWYR = What You
See Is What You Record).
•
CVBS-TXT-OUT, CVBS for TXT and Comb filter.
•
CVBS-TER, video signal from the tuner is fed to the I/O
switching and to EXT1 on pin 19 of SCART.
F21RE AB
9.
EN 95
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