| 摘要 |
An auto chroma filter averages the value of successive color burst amplitudes on a line-by-line basis over many video frames, by fetching a burst value from memory and loading it into an up/down counter, and also into a D/A converter which provides the chroma filter output signal. A comparator compares an incoming new burst value with the output signal, whereby the counter increments or decrements the value toward the incoming new burst value in response to the comparator. The updated value then is loaded back into memory in the same location from which it was fetched, and the cycle continues for each video line and successive frames.
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