Method and apparatus for reducing video data memory in converting VGA signals to TV signals
 It is disclosed herein that a system for reducing video data memory in VGA-to-TV converters that convert computer video signals to TV compliant signals for display on regular TV screens. By closely tracking two pointers, one being a write pointer responsible for writing incoming video data into the video data memory and the other being a read pointer responsible for reading out the stored video data in the video data memory, the memory is efficiently used for buffering the video data. To ensure that the read pointer always retrieves the valid video data at its own speed, an address monitoring process is provided to monitor the address difference between the write pointer and the read pointer. When the monitoring process detects that the read pointer may soon surpass the write pointer, a control process is placed on the write pointer to prevent the read pointer from passing over the write pointer. Depending on the speed difference between the write and read pointers, the writer pointer is either paused for a frame time or assigned to a secondary write pointer that writes data into the memory just visited by the read pointer. The efficient use of the memory makes it possible to reduce the memory capacity to a minimum so as to reduce the cost of manufacturing the converters. 
Aitech Int'l Corporation
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Xiao Chuan
Li