| 摘要 |
In a digital composite video processing system where the video signal has a color subcarrier Fsc, horizontal and vertical sync signals and produces multiple color fields, and where the system has system clock of frequency nFsc for digitizing and a horizontal counter counting to L incremented by the system clock, a method and apparatus is disclosed for synchronizing the system clock to color burst and synchronizing the horizontal counter to horizontal sync, whereby a window of width W clock counts wide is selected such that HSYNC is desired to occur at clock pulse P+W/2 when P is an integer; a determination is made whether HSYNC occurs before, within or after the window, the system counter is reset at counts L-(n/2), L, or L=(n/2) determined by where HSYNC appeared in relation to the window, and color reference signal is sampled to determine which of the four color fields is being processed, all in order to properly process the color video signals.
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