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RGB input from the VGA connector
From the VGA input, a differential RGB signal goes to the input ADC (MST 9883). This chip looks at the vertical, horizontal. From there, the signal is converted to a 24 bit digital signal and sent to Scaler chip via the digital bus. The VGA connector also accepts differential inputs for direct processing. A software lookup table is used to determine what type of signal is present. The input ADC sets up a phase lock loop and locks onto the frequency.
Video processing
From the digital video bus, the signal next goes to the frame memory in the Scaler IC (gm6015). Scaler manages the frame buffer to perform frame rate conversion. The frame memory is asynchronous, meaning the input rate is different than the output rate. From this point on the vertical and horizontal frequencies will not change. The frame memory accepts information a page at a time. When one page is displayed, another page is already in the frame buffer. In the DVR5610, which has a native 1280 X 720 resolution, video inputs of 1280 X 720 and lower are converted by the frame buffer to 75 Hz frame rate. The converted frames are then passed to the Scaler IC for resizing up to 1280 X 720. The DVR5610 does not resize images larger than 1280 X 720. In the DVR5610 Zoom model, Higher resolution is first resized down to 1280 X 720 by dropping lines and pixels, then converted by the frame buffer to 75 Hz frame rate, and finally passed to Scaler as 1280 X720 at 75 Hz. Video inputs of resolutions lower than 800 x 600 are converted by the frame buffer to 75 Hz frame rate and passed to the Scaler for resizing up to 1280 X720 The Scaler also provides the following support functions: � Dual digital video inputs for MAIN and PIP display � Dual bi- level / tri-level sync separators � �pixel-based� motion adaptive de-interlacing � 2:2/3:2 inverse pull-down film processing � arbitrary shrink/zoom scaling on both MAIN and PIP channels � �3D� noise reduction filter � Color space conversion � Color controls � Video look up table(VLUT) and multi-image PIP display The Scaler provides high-quality resizing of VGA, SVGA, NTSC, PAL and SECAM inputs up to the 1280 X720
Delta Products 55 Confidential 05/10/2003
