Samsung DVD-HR755, Руководство по обслуживанию

Страница: 117 / 132

Circuit Operating Descriptions
Samsung Electronics 13-7
13-3-2 Video Switch (HAII8827)
IC216(HA118827) switch whole the I/O signals of jack block. This swith IC is controlled by I2C protocol between
FIC1(IO front micom) it select one of the input video signal among the RF signal(pin14), AV1(pin12), AV2(pin10),
front AV3(pin8).
Selected video signal pass to video decoder(TW9909) and DIC1(codec chip) through the pin35.
DIC1(codec chip) decode MPEG2 video format and output analog S-video(Y,C) and componect(Y,Pb,Pr) to IC216.
Y(pin31),C(pin32) signals are superposed to composited video(pin 17) and this signal outputted to Scart AV1 and
composite RCA video.
S-video and component video signals are inputted through pin31(s-video Y), pin33(C),pin27(component Y),
pin28(component Pb),pin29(component Pr). And IC216 include 6dB amplifier.
Based on CVBS signal, the final output level must be 2Vpp without 75ohm terminal resistance.
Because the level of video encoder output is only 1Vpp, the level is adjusted with the special amplifier.
Y, C, Y(R), Cb(B), Cr(R) signals of which gain is adjusted by amplifier is outputted to pin17(composite), pin21(Y),
pin19(C), pin25(Y/G),pin24(Pb/R), pin23(Pr/B).
Fig. 13-7