TW9912

The TW9912 is a low power NTSC/PAL/SECAM video decoder chip that also supports analog component video as an input. The video decoder decodes the base-band analog CVBS or S-video signals into digital an 8-bit 4:2:2 YCbCr format. The analog component video is digitized into an 8-bit YCbCr format. The digital output supports standard BT. 656 format for interlaced video. It can also output progressive BT. 656 format when receiving a progressive component input or by converting interlaced video into progressive format via an internal de-interlacing engine. TW9912 uses the 1. 8V for both analog and digital supply voltage and 3. 3V for I/O power. A single 27MHz crystal is all that needed to decode all analog video standards. This chip consists of an analog front-end with input source selection, a variable gain amplifier, analog-to-digital converters, a Y/C separation circuit, a multi-standard color decoder (PAL BGHI, PAL M, PAL N, combination PAL N, NTSC M, NTSC 4. 43 and SECAM) and synchronization circuitry. Y/C separation is done with a high quality adaptive 4H comb filter for reduced cross color and cross luminance. The advanced synchronization processing circuitry can produce stable pictures for non-standard and weak signals. The output of the decoder is line-locked to its inputs. TW9912 also includes circuits to detect and process vertical blanking interval (VBI) signals, including closed caption and WSS. It slices and process VBI data for output by register readout through the host interface. It also detects analog copy-protected signals that contains AGC and colorstripe pulses. A 2-wire serial host interface is used to simplify system integration. All the functions can be controlled through this interface.