AL128 Plug & Play VGA to NTSC/PAL Scan Converter |
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The AL128 PC to TV scan converter chip accepts graphic data up to 1024x768 resolution from PC and Macintosh graphics controllers and converts it into broadcast-quality NTSC or PAL TV signals. In addition to analog RGB data, 24-bit digital RGB data can be input into the AL128 converter chip to maintain the best video quality and avoid noise problems. This new chip is pin-to-pin compatible with the AverLogic AL100 but provides analog RGB output for SCART implementation. An integrated high-quality anti-flicker filter (SmartFilter TM ) in the AL128 removes the unpleasant flicker caused by the interlaced display of high contrast graphics while maintaining the original clarity and sharpness of informative data such as natural pictures and text. With 512 Kbytes of memory, plug-and-play is achieved by automatically detecting the scan rate and resolution of the incoming graphic signals without the use of software. With less memory than other solutions on the market, high resolution data is processed and stored using a complex and proprietary buffer management system. No compromise is made at all with video quality by using either compression or sub-sampling algorithms. AL128 Characteristics
Functional Description The major functions of the AL128 can be accessed using four push buttons combined with the on-screen-menu feature, this eliminates the cost of a micro-controller and complex control panel. The superior quality scaling algorithm, which reduces the jagged-edge artifacts from line dropping , can smoothly fit graphics of 640x480 (up to 100 Hz) and 1024x768 (up to 75Hz) resolutions into the visible region of the NTSC or PAL screen. Both horizontal and vertical sizes can be linearly adjusted. Additional features include eight levels of flicker control using 5-line filter, zoom control and picture freeze. This highly integrated mix-signal chip, packaged in 24mm x 24mm 160-pin LQFP is powered by a single 5-volt power supply. Power-down is achieved by using either hardware or software control. The enhanced features and superior quality make the AL128 very suitable for PC video to TV conversion in PC ready televisions, scan converter boxes, VGA add-on card, or network and laptop PCs. Either analog RGB or digital RGB data can be input to the chip. The analog RGB data is digitized by three 50Mhz 8-bit video A/D's and is converted into 24-bit digital RGB data. For graphic controllers with standard or proprietary digital RGB output such as a high-color feature connector, VAFC, or flat panel interface, the optional 24-bit digital RGB interface provides a solution for optimal video quality. The 24-bit digital RGB is passed to the digital processing unit of the chip. This DSP unit performs scan conversion operations and other digital signal processing such as flicker filtering, YUV filtering, scaling and color space conversion in the digital domain. The processed video data is sent to the digital TV encoder for converting into broadcast quality composite and S-video signals or original RGB format, which are in turn converted by three 9-bit D/A converters into analog outputs. Functions can be controlled by dedicated hardware pins as well as software. The I 2C interface provides full software programmability. The aforementioned hardware and software programmability also applies for the power-down feature. Alternatively only four push buttons are required to control the major functions such as sharpness, pan, zoom, brightness, color bar output and position centering without the use of software or microcontroller. Applications
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