Techwell's TW9906 is a high quality NTSC/PAL/SECAM video decoder that is designed for multimedia applications. It uses the mixed-signal 2. 5V/3. 3V CMOS technology to provide a low-power integrated solution. The TW9906 analog front-end is equipped with three separate analog channels that enable it to accept all three possible analog video signal standards: composite, S-video or YCbCr component video. All channels include an analog multiplexer (MUX) for maximum flexibility in software controlled input selection. It is possible to connect up to five composite inputs at one time and allow the software to switch between them. Alternatively several combinations of composite inputs and S-Video component inputs may be switched under software control. (Four input channels of any format can be accommodated with but there is a maximum of 2 S-Video inputs or 2 component inputs. ) The front-end contains all the necessary circuits to simplify the system design. The built-in three high quality 10-bit analog-to-digital converters (ADCs) convert inputs into digital signals for processing. The TW9906 uses proprietary adaptive 4H comb filter for chroma and luma separation to achieve high video quality. The image enhancement includes horizontal and vertical peaking, CTI and BCS control. The advanced synchronization processing can produce stable pictures for non-standard signal such as those produced by VCR trick mode. The high quality scaler uses multi-tap poly-phase decimation filter to accurately scale down the image with minimum phase error. It can be programmed to scale-down the output picture to an arbitrary ratio with cropping. The TW9906 supports flexible pixel interface. It outputs YCbCr (4:2:2) data stream over 10-bit or 20-bit data path. It also supports both free-running clock and line- locked clock output. A 2-wire serial MPU interface is used to simplify system integration. All the functions can be controlled through this interface.