Philips EM7U LCOS, Service Manual

Page: 37 / 104

PIP/DOUBLE WINDOW INPUT (Figure 37)
The PIP/Double Window panel allows for both a standard PIP window and a split screen.
The PIP/Double Window module has a separate Tuner, SAW filter, and Signal Processor.
The output of the Signal Processor, 7301, on Pin 16 is fed to switching IC 7402 that selects
between the PIP Tuner and Composite Video from the SSB. Selected Composite Video for
the main picture is output on Pin 15 of 7402 and is fed to the SSB. Selected Composite
Video for the PIP window is output on Pin 14 and is buffered by 7421. It is fed to 1333, a
4.5MHz Trap. It is then buffered by transistor 7331 before being fed to Pin 24, which selects
between the selected Tuner Video or selected Composite Video from the SSM. Composite
Video is fed to a YC separator, then to a Delay Line and Demodulator. If it is a YC signal, it
bypasses the YC separator. The YUV signal is then fed to the YUV switch, which selects
between the output of the Delay Line and Demodulator, and external YUV from the Large
Signal Board. The YUV (SY, SU, and SV) is output to the PIP processor IC. Selected
Composite Video is fed to the V-Chip processor. V-Chip processing for the main picture is
done by the Microprocessor on the SSB.
DOUBLE WINDOW PIP OUTPUT (Figure 38)
The PIP or Double Window YUV signal is fed to the PIP/DW processor, 7801. The I 2 C buss
controls the IC from the Microprocessor on the SSB. The PIP/DW processor outputs YUV for
the PIP window or Split Screen to the YUV switch, 7803, where it is mixed with the YUV sig-
nal from the SSB for the main picture. The Fast Blanking line from 7801 on Pin 68 controls
the switch point in which the PIP window or Split Screen is inserted. The +3VD line switches
the SDA and SCL lines. The PIP processor is powered by the +3 volt supply. The +3.3 volt,
+3 volt, and +3VD volt supplies are produced by regulator 7802 which is driven by the +5VS
supply. This supply is switched On when the PIP window is selected.
DOUBLE WINDOW CONTROL AND POWER SUPPLY (Figure 39)
The PIP/Double Window module is controlled by the I 2 C buss through 7403 on the PIP mod-
ule. Pins 4, 5, 6, and 7 perform Video selection functions. Pin 10 produces a reset signal for
the Guide Plus module. Pin 12 controls the +5VS and +8VS supplies.
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PIP/DW PANEL