Hitachi 61HDX98B Manual page 12

BLOCK DIAGRAM EXPLANATION
SYSTEM CONTROL AND SIGNAL PROCESSING
MAIN VIDEO FROM SELECTOR IC:
At the bottom left hand side is shown the Main Video
from Selector label. This is the NTSC video from the
selector IC. This is routed to two blocks.
3D Y/C:
The 3D Y/C separates luminance from the chroma. It
also add the 3D effect, (if the 3D Y/C is turned on
within the menu). Noise is canceled and the two sepa-
rate components are output to the Video/Chroma De-
modulator.
VIDEO/CHROMA DEMODULATOR:
This IC decodes the signal down to it's Luminance and
Chroma. components and outputs it as 1HYIQ.
DM-1 I/F:
Noise cancellation and level shifting preparing the sig-
nal for the DM-1 module.
1HYIQ:
1HY = Standard NTSC format luminance. (Also
known as 480I).
I and Q = Standard NTSC format, demodulated
chroma components.
SYNC DET.:
Separates the Sync signal from the composite video sig-
nal.
SYNC DET.:
This block outputs composite sync to the PinP unit which
is used for timing for display. This is specifically related
to the Demodulator, D/As and Read/Write clock. The
Read/Write clock also is controlled by the frequency of
the Subcarrier also called fsc.
The Composite sync is also sent to the DM-1 on the line
labeled as 1H Composite Sync. The DM-1 uses this sig-
nal for OSD positioning, auto channel detection and AFC
loop activation.
TV uCOM MICROPROCESSOR:
This is the slave Microprocessor or Sub-Microprocessor.
This IC is in constant communications with the DM-1
module. The slave uP. Receives or outputs the following
signals;
HBLK: = Input; this is the Horizontal Blanking signal.
Used for Service OSD signal creation timing.
S.WIDE: = Output; when the customer watches regular
NTSC 4X3 aspect source, they have a choice of viewing
the signal in one of 4 ways.
Normal: This will display a standard 4X3 picture
with black panels on each side of the picture.
Fill: This will expand the picture to fill the screen.
The top and bottom will be cropped.
Full: This will expand the picture side ways and fill
the screen. However the picture will be non-linear.
Smooth Wide: This will keep the center of the pic-
ture linear and stretch the outside edges to fill the
screen.
With the four choices above, the DM-1 module controls
the signal for 3 of them; Normal, Fill and Full. However,
during Smooth Wide, the deflection circuit is switched to
perform the stretching of the sides. The slave Microproc-
essor outputs S.Wide during this time.
CUT OFF: = Output; labeled as V. Stop, during the Ser-
vice adjustments for Cut Off, (Screen Background con-
trols), the vertical must be collapsed. This output causes
the B+ to the vertical output IC front end to be grounded
and grounds the vertical trigger pulse called V. Saw.
D. SIZE: = Output; labeled as Digicon Size, during
Smooth Wide mode, the Digital Convergence Unit, hear
after called DCU, must know that the set is in the dis-
torted deflection mode. This signal tells the DCU just
that.
MAGIC SW: = Input; when the customer presses the
Magic Focus button on the control panel, the DCU noti-
fies the slave micro. That it is busy performing Magic
Focus. The slave micro. Notifies the DM-1 module and
the DM-1 module ignores infrared pulses from the re-
mote control.
CLOSED CAP. DATA: = Input; This input receives the
composite sync signal and decodes the Closed Caption
Data. (Data Slice line 21) and the communicates with the
DM-1 Module. The DM-1 Module actually introduces
the Closed Caption Characters into the Video stream.
F. PANEL: = Output, Dependant upon the customer's
menu selection, will determine the IRE level of the side
panels when 4X3 Normal mode is used. By raising the
side panel IRE levels, the 4X3 picture won't burn in the
CRT's.
MAIN SYNC DET: = Input; this is used for detecting the
Closed Caption Data. This information is routed to the
DM-1 module for OSD generation. NOTE: the sub-
micro. Doesn't produce OSD characters for Closed Cap-
tion.
PinP SYNC DET: = Input; PinP tuner sync is routed to
the sub-micro. And is used during PinP tuner channel
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