Circuit Descriptions, List of Abbreviations, and IC Data Sheets
9.
•
Two RGB inputs.
9.7.2
Outputs
One can select three separate, switchable outputs:
•
One YUV-output, which is fed to the PICNIC.
•
Two CVBS outputs, one for CC-decoding (CVBS-TXT) and
the other for MONITOR out to have WYSIWYR (What you
see is what you record).
9.7.3
Video Processing
The HOP will generate synchronization signals derived from
the feature box (PICNIC, pin 60 and 61) signals.
If a VCR is connected, there is also an automatic correction for
MacroVision (r). This is active for the external sources.
The HIP itself (no external voltage) controls the Y/C switch in
the HIP.
The chrominance decoder in the HIP is full multi-standard, but
only NTSC is decoded.
A sync separation circuit is integrated in the HIP; the HIP
delivers the HA50 and VA50 to the PICNIC and DW-panel.
The quartz crystals can be connected without any alignment.
They are also used as a reference for the synchronization. A
digital control circuit that is locked to the reference signal of the
color decoder determines the start-up of the sync.
Note:
If the crystal must be replaced, you must use only the
genuine replacement part. This crystal is very precise: if it is
replaced by another type of crystal, there may be no color,
because of a different capacity.
9.8
Video: Feature Box (Diagram B3)
9.8.1
Introduction
The basic function of the Feature box (FBX6) is picture
improvement, and depending on the version, several scan
conversion methods are possible. The feature box is integrated
on the SSB, and the PICNIC (SAA4978H) is the key
component.
The PICNIC is used for the 60 Hz (prog. Scan) conversion. It
has the following functions:
•
The ADC/DAC conversion.
•
Interlaced to progressive scan conversion.
•
Dual screen compression
•
The Panorama mode.
•
Automatic Aspect Ratio Adaptation (AARA)
•
Color Transient Improvement (CTI)
•
The contrast improvement (Dynamic Contrast).
All these functions are integrated in one IC: SAA4978H, 160
pins QFP.
The 60 Hz YUV signals, coming from the HIP, are fed to the
PICNIC via an anti-aliasing filter.
The (AABB) frame frequency doubling is done by the PICNIC
(SAA4978, 160 pins QFP) together with a field memory
(MEM1).
This IC has an internal CPU and a (small) integrated ROM. The
actual FBX software is located in an external ROM (item 7711).
In order to limit the number of connections between the PICNIC
and the external ROM, a number of lines are used twice. The
lines A8 to A15 are fixed lines, while the lines A0 to A7 are
made switchable with the eight data lines of the ROM. This is
done via a Latch (item 7712) that is controlled by pin 139 of the
PICNIC (the 'ALE' signal). Via bus 'C,' a digitalized signal is
presented to FM1 (Field Memory 1), which is used for the 60 to
120 Hz conversion.
9.8.2
ADC/DAC conversion
•
Analog to Digital conversion is done with three identical 9-
bit ADCs.
•
Digital to Analog conversion uses three identical 10-bit
DACs.
In the PICNIC there are three nine-bit ADCs present for Y, U,
and V. For digitizing the Y (luminance), nine bits are used (to
realize a more detailed picture). These nine bits are only
internally used. Via dithering, the nine bits are reduced to eight
bits and this data is stored into memory. The data in the
memory is fed back to the PICNIC and via un-dithering the data
is again reproduced to nine bits for processing.
U/V (color difference signals) is also sampled with nine bits.
These two nine bit data streams are multiplexed to four bit data
streams. As the perception of colors by the human eye is less
sensitive to luminance, this reduction is allowed.
9.8.3
Interlaced to progressive scan conversion
The main task of the PICNIC is the conversion from interlaced
to progressive scan (60 Hz) for YUV and HV-sync. In order to
remove 'large area flicker' (especially visible in a white picture),
the field-rate of the video is doubled by the FBX6. The 16 kHz
line frequency is doubled. When the video input contains fields
A, B, etc, the conversion provides an AABB sequence on the
display. The actual conversion is done in the first Field Memory
by reading it twice at double speed, while writing it once.
9.8.4
Dual Screen Compression.
The PICNIC can provide horizontal video compression up to 50
%. The compress mode can be used to display dual screens.
9.8.5
The Panorama Mode.
To fit 4:3 pictures into a 16:9 display, it is possible to apply a
panoramic horizontal distortion, to make a screen-fitting picture
without black sidebars or lost video. The center horizontal gain
is programmable and the side gain is automatically adapted to
make a screen-fit.
9.8.6
Automatic Aspect Ratio Adaptation (AARA)
This feature uses data from the 'black bar detection circuit' to
adapt the vertical and horizontal amplitude to an aspect ratio
belonging to the display without showing the black bars.
9.8.7
CTI
At CVBS video signals, the bandwidth of color signals is limited
to 1/4 of the luminance bandwidth. Transients between areas
of different color are therefore not very sharp. The PICNIC can
increase these transients artificially with a time manipulation
algorithm.
9.8.8
Dynamic Contrast
To make the contrast (black/white) range wider, Philips has
invented Dynamic Contrast. It uses the digital memory used in
digital scan sets. It measures every A-field (25 x/s) and digitally
analyzes where on the grayscale most of the image is located.
If it is a relatively dark image, the lighter part of that image is
stretched towards white, so that more contrast will become
visible in that picture. If it is a relatively light image, the darker
part of that image is stretched towards black, so that these
darker parts will have more contrast. When the image is in the
middle of the grayscale, both dark and light parts are stretched.
Summary of Contents for EM1.1A
Page 35: ...Circuit Diagrams and PWB Layouts 35 EM1 1A AA 7 Layout LSP Top Side ...
Page 37: ...Circuit Diagrams and PWB Layouts 37 EM1 1A AA 7 Layout LSP Overview Bottom Side ...
Page 38: ...38 EM1 1A AA 7 Circuit Diagrams and PWB Layouts Layout LSP Part 1 Bottom Side ...
Page 39: ...Circuit Diagrams and PWB Layouts 39 EM1 1A AA 7 Layout LSP Part 2 Bottom Side ...
Page 40: ...40 EM1 1A AA 7 Circuit Diagrams and PWB Layouts Layout LSP Part 3 Bottom Side ...
Page 41: ...Circuit Diagrams and PWB Layouts 41 EM1 1A AA 7 Layout LSP Part 4 Bottom Side ...
Page 116: ...116 EM1 1A AA 7 Circuit Diagrams and PWB Layouts Personal Notes E_06532_013 eps 131004 ...
