描述 Description

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.

特性 Features

? NTSC (M, 4.43) and PAL (B, D, G, H, I, M, N, N combination), PAL (60), SECAM support with automatic format detection
? Software selectable analog input control
? Built-in analog anti-alias filter
? Fully programmable static gain or automatic gain control for the Y channel
? Programmable white peak control for the Y channel
? 4-H adaptive comb filter Y/C separation
? PAL delay line for color phase error correction
? Image enhancement with peaking and CTI
? Digital sub-carrier PLL for accurate color decoding
? Digital Horizontal PLL for synchronization processing and pixel sampling
? Advanced synchronization processing and sync detection for handling non-standard and weak signal
? Programmable hue, brightness, saturation, contrast, and sharpness
? Automatic color control and color killer
? Chroma IF compensation
? VBI slicer supporting CC and WSS data services
? Programmable output control
? Triple 10-bit ADCs with independent clamping and gain control
? Supports 480i/480p/576i/576p analog component input with SOG
? ITU-R 656 compatible YCbCr(4:2:2) output format
? Progressive ITU-R 656 output format support for both interlaced and progressive inputs
? Two wire MPU serial bus interface
? Power save and Power down mode
? Low power consumption
? Single 27MHz crystal for all operations
? 3.3V tolerant I/O
? 1.8V/3.3V power supply
? 48 pin QFN package