Circuit Descriptions and Abbreviation List
EN 123EM5A P/M 9.
The OTC will generate an error code to indicate what was
wrong.
OSD/TXT
The horizontal (H
D100
) and vertical (V
SYNC
) sync pulses are also
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.
9.4.2 I
2
C Bus
In the EM5A chassis with OTC-processor there are three I
2
C
busses used:
• Slow (max. 100 kHz) hardware I
2
C-bus, called I
2
C1, used
for the Tuner.
• Fast (max. 400 kHz) hardware I
2
C -bus, called I
2
C2, used
for all ICs.
• Separate short bus, called I
2
C3, for the Non Volatile
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).
9.5 Tuner & IF (Diagram A8 & B2)
The tuner is I
2
C controlled, and is capable of receiving off-air,
S- (cable) and Hyperband channels:
• Low (44 - 156 MHz).
• Mid (156 - 441 MHz).
• High (141 - 865 MHz).
The tuning is done via I
2
C. The reference voltage on pin 9 is 33
V. This voltage (V
TUN
) is derived from the secondary side of the
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 AV1 (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-
norm) modulated signal is available on pin 5 and is fed to the
audio demodulator MSP34xx (7651).
9.6 Video: HD Jack Interface (Diagram N)
The Jack High Definition module covers the following functions:
1. RGB output selection.
2. Matrix circuit to convert YPbPr to RGB.
3. Sync slicer for YPbPr sync on Y, RGB sync on Green.
4. Sync selection.
5. Control Function.
6. Audio feed-through of signal source.
Figure 9-11 Source Selection
9.6.1 RGB Output Selection
The module has two video inputs and one RGB output (going
into the set.)
The inputs can also handle 1080i-signals and 480p-signals
(both in RGB format and YPbPr format.)
(This selection circuitry is also needed to cope with the various
formats of the non-standardized HD set top box business.)
Video-input (3 cinches, reference number 1993-A-B-C):
• YPbPr with sync on Y.
• RGB with sync on green (note: cinch-inputs are normally
used for YPbPr input.)
Video-input (D-sub, reference number 1990):
• YPbPr with sync on Y (note: D-sub input is normally used
for RGB-inputs only.)
• RGB with sync on Green.
• RGB with separate H and V Sync (called VGA in 480p.)
RGB Output:
H-770-3
H-770-2
RGB_ATSC
RGB_PAL
SND_R_in
SND_L_in
SND_R_out
SND_L_out
FBL
A
B
A,B
RGB output
H_out
V_out
FBL
I03I01
I04 I05 I06
I02
I/O Expander: M62320
SYNC SELECT 2
SYNC SELECT 1
TRISTATE SYNC
MATRIX SELECT
TRISTATE RGB
RGB SELECT
PAL
MATRIX
ATSC
MATRIX
TDA8601
SW1
TDA8601
SW2
2fH
Sync slicer
HEF 4052
SW-3
1,2
1,2
3
3
V-770
CL 16532043_024.eps
050601
YPbPr/
RGB
H_in
V_in
I2C
Y/G
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