Signal Pb Ass'y - Panasonic BT-M1950Y Service Manual

Signal PB ASS'Y
Composite video, Y/C, component and RGB signal inputs from the input PB ASS'Y are applied via connector 002 (CN002).
The input signals are not differentiated between PAL and NTSC systems.
1. Y/C separator circuit
The composite video signal input via CN002 pin 2 is branched in three lines. The first goes through the chroma trap of
0113, 0114, 0116 and 0118 to produce the PAL Y (PAL Y) signal applied to IC101 pin 2. The second is applied as
the PAL chroma (PAL C) signal to IC202 pin 12. In the third line, the NTSC Y/C separator circuit of DL 101, DL 102 and
0104 - 0109 separates the NTSC Y (NTSC Y) and NTSC chroma (NTSC C) signals. The NTSC Y signal is applied
through the 0117, 011 0 and 0118 amplifier and buffer to IC101 pin 1. The NTSC C signal is applied to IC202 pin 13.
• Y signal flow
The 358 signal from the MPU selects between the NTSC and PAL Y signals at IC101 pins 1 and 2. NTSC is
selected when the 358 signal is High level. This output goes from pin 15 to pin 13. The Y signal from the S input
terminal (YC Y) via CN002 pin 6 goes to pin 12. The signals at pins 12 and 13 are then selected. When the V/-YC
signal from the MPU is Low level, YC Y is selected. The output from pin 14 is sent through 0108 to pin 12 of the
IC305 analog switch.
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signal flow
The 358 signal from the MPU selects between the NTSC and PAL C signals at IC202 pins 12 and 13. NTSC is
selected when the 358 signal is High level. This output goes from pin 14 to pin 1. The C signal from the S input
terminal (YC C) via CN002 pin 4 goes to pin 2. The signals at pins 1 and 2 are then selected. When the V/-YC
signal from the MPU is Low level, YC C is selected. The pin 15 output is sent through 0201, 0202, T01 and 0203
to pin 3 if NTSC and to pin 5 ii PAL. These are selected by the -443 signal from the MPU and applied to the
demodulator IC201 via pin 4. The color difference signals are then sent via amplifier and buffer circuits to the IC305
analog switch.
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