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68
TPF1.4A LA
Circuit Description
MM tuner is used to receive RF wave and output CVBS and 2nd IF signal. CVBS is to video decoder (SAA7119) for
color process, 2nd IF is to sound decoder (MSP34x5) for audio process. The tuner control is via IIC ex. channel tuning.For
different TV system, tuner and sound decoder have diversity as above.
Standard TV input (Tuner, S-video, CVBS, SCART) is processed by SAA7119, But YPbPr, SDTV and HDTV(480i,
576i,480p,576p,720p,1080i), is done by scaler MST51512L/502L ADC. But the signal is still link to SAA7119 if PIP (video
in graph) functionis requested. Then all YPbPr signal processed by SAA7119 could be the PIP video source. (* May use
down sampling in HD0) MV protect is decoded by scaler.
Video decoder SAA7119, is in charge of color decoding, could support PAL, NTSC and SECAM world wide
system. Compare to SAA7118, SAA7119 improve some picture quality, like V-chip CC I2C read-back, LTI, CTI, skin tone
correction(see task A), also the HD0 is supported .
Teltext function is for AP model, need a extra IC SAA5360. CVBS input, R/G/B, FB, out. Due to the SAA5360 request
input signal 1Vrms and only one input channel, so the CVBS input source is from SAA7119 AOUT (CVBS out with 1Vrms).
The R/G/B FB output into SAA7119 by AI22/AI32/AI42, and AI44 could overlay on any video source.
Sound decoder MSP3415/45 is responsible to sound decode of tuner 2nd IF. It has one 2nd IF, two selectable audio
sources input.
And one loudspeaker, one scart out. Due to the input port limitation, a MUX is added for AV source select( PC audio
in is fix in SC1). If the post audio amplifier is gain fixed type then the volume adjust will be on MSP34XX.
Scaler MST51502L/51512L besides scaling function, PIP, 3D de-interlacer, color enhance are major feature.
Even de-interlacer is not so good but for static picture is enough to avoid image sticking.
The scaler structure limitation, the PIP source only from video port , 8 bits or 16 bits. The sub window /PIP size can
enlarge to half screen.
MCU, NT68F632AL, is 128K flash ROM inside. Power control, RC5 I/O, and key function all done by here.
All chip communication i
9. Trouble Shooting
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