Sony KP 48S70, Training Manual

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23
Picture in Picture (S Model)
Overview
The PIP circuit is capable of taking any of the three types of inputs and
compressing them. The compressed output is sent to the YCJ to be
placed into the main picture. Only the sub input signals are needed for S
models, unlike the V models which required sub and main picture inputs.
The component video input can also be processed here for display as a
child picture.
Sub Y Signal
The sub Y signal from IC1101 A/V Switch is split to three different places.
They are:
ƒ
Through Q1914 Y Buffer for component when a component input is
selected for the main or sub picture.
ƒ
IC1602 Sub V Chip to determine if the child picture should be dis-
played in the PIP window.
ƒ
IC1902 Sub Decoder to decode the Y and C signals. Y is also used
for H and V sync.
Sub Decoder, PIP Processor and YUV Switch
IC1902 Sub Decoder decodes the SY and SC signals. The decoded Y
and C signals, now YUV, are output from IC1902/18, 19 and 20 respec-
tively.
These signals are then input to IC11903/2, 12 and 5. IC1902 has another
set of YUV signals input at pins 1, 13 and 3. The Y signal is the SY signal.
The Sub U and V signals come from the Video 3 component input at
J1106. IC1903/9, 10 and 11 are connected to IC1904/3 DVD SW. IC1904
is a D/A Converter that outputs a voltage level dependent on the data it
receives. This voltage level selects which input is used for the sub pic-
ture. The selected YUV signals are output at IC1903/15, 14 and 4 to
IC1905/28, 30 and 32.
IC1905 is the PIP Processor. It digitizes and compresses the input sig-
nals. It then converts the compressed signal back to analog and outputs
YUV at pins 8, 9 and 7. These signals are input back into IC1902 Sub
Decoder at pins 11, 12 and 13. They are passed through an auto pedes-
tal circuit and output at IC1902/8, 7 and 6. IC1905 also outputs two con-
trol signals, M H Sync and SEL. The M H Sync signal will be used to
create a gray screen during Auto Program and Favorite Channel func-
tions. The SEL line becomes the YUV Switch input to the YCJ and YUV
Controller.
Sub C Signal
The Sub C signal is input through Q1906 Buffer to IC1902/32 C In. This
signal will be decoded to its component form.