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EN 110
9.
9.4.1
OTC
Introduction
The SAA5801 (IC7001) is called the OTC (OSD, TXT, and
Control). In this IC, the microprocessor and the TXT-decoder
(level 2.5) are integrated.
Some of its functions are:
•
Set control.
•
TXT/OSD acquisition.
•
RGB-outputs to the HOP
•
Menu blending; for blending the contrast, software
controlled.
2
•
I/O-ports for I
C, RC5/RC6, LED, and service modes.
•
Error code generation.
Data Storage
•
The software for EM5E can be 2 MB (Megabyte), and is
stored in IC7006.
•
It is possible to store 1200 TXT pages in IC7007. This is a
DRAM of 4 MBit and this IC is also used to store data of a
working set.
•
For EPG a Flash-RAM (7012) is used.
•
The Non Volatile Memory IC7011 is a 4 kB version
M24C32W6.
Power Supply
All ICs in this part are supplied with 3V3. For this voltage, a 3V3
stabiliser is used (IC7005).
With the circuitry around TS7003 and 7004 (diagram B5), a
reset is generated to wake up the OTC (pin 74). During this
reset, all I/O pins of the OTC are made 'high'.
Via pins 105 and 106, the +8 V and the +5 V are sensed. If one
of them is not present, the Main supply is switched 'off' (set in
protection and the red LED will blink at 3 Hz).
The OTC will generate an error code to indicate what was
wrong.
OSD/TXT
The horizontal (H
) and vertical (V
D100
fed to the OTC for stable OSD and TXT.
The RGB-outputs (77/78/79) together with fading (pin 80) are
fed to the HOP. The fading pin has a double function: it is used
for making a transparent menu and as fast-blanking signal for
TXT.
2
9.4.2
I
C Bus Specifications
In the EM5E chassis with OTC-processor there are three I
busses used:
•
Slow (max. 100 kHz) hardware I
for the Tuner.
•
Fast (max. 400 kHz) hardware I
for all ICs.
•
Separate short bus, called I
Memory (NVM), to avoid data corruption.
9.4.3
NVM
The Non Volatile Memory contains all set related data that must
be kept permanently, such as:
•
Software identification.
•
Operational hours.
•
Error-codes.
•
Option codes.
•
All factory alignments.
•
Last Status items for the customer + a complete factory
recall.
•
Txt featuring (keeping habit watch data).
•
EPG data.
EM5E
Circuit Descriptions and Abbreviation List
) sync pulses are also
SYNC
2
2
C-bus, called I
C1, used
2
2
C -bus, called I
C2, used
2
C3, for the Non Volatile
9.5
Tuner & IF (Diagram A8 & B2)
The tuner is I
S- (cable) and Hyperband channels:
•
Low (44 - 156 MHz).
•
Mid (156 - 441 MHz).
•
High (141 - 865 MHz).
The tuning is done via I
V. This voltage (V
standby supply, via D6110 and R3116//R3115 and a 33 V
zener diode (D6200). 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. An extra filter (5403), tuned
at 40.4 MHz, is necessary for L/L' sets (with 6.5 MHz sound),
to suppress the neighbour channel.
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 mis-aligned, if the picture
deforms with a perfect signal. Then the IF-circuit amplifies 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 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.
Then the signal is again fed 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 (monitor
out) and again back into the HIP (pin 14) to the source/record
selection.
To realise Quasi Split Sound (QSS), the IF-signal is fed to the
HIP on pin 63/64 via SAW-filter 1405. The FM (or AM for L-
2
C
norm) modulated signal is available on pin 5 and is fed to the
audio demodulator MSP34xx (7651).
9.6
Video: High-end Input Processor (HIP,
Diagram B2)
In the EM5E, the HIP TDA932xH is used, which contains the
following functions:
•
IF demodulation.
•
Group delay correction.
•
AFC signal generation, used to track drifting transmitters.
•
Sound carrier re-generation (SIF).
•
AM demodulation.
•
Sync acquisition, delivering HA, and VA.
•
Switching off IF-filtering.
9.6.1
Inputs
The HIP has various inputs:
•
Full matrix switch with:
–
Two CVBS inputs.
–
Two Y/C (or additional CVBS) inputs.
–
One CVBS front-end input.
2
C controlled, and is capable of receiving off-air,
2
C. The reference voltage on pin 9 is 33
) is derived from the secondary side of the
TUN
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