摘要 |
An automatic hue control system for a color television receiver using a single sampling of a vertical interval reference (VIR) signal to establish the hue setting of the receiver. A VIR signal periodically appears during a pre-selected line in the vertical blanking interval of a broadcast video signal and includes a chrominance reference portion of such phase that one color difference signal as detected should be zero and another portion having no chroma content. Sampling of the VIR signal during at least a portion of the chrominance reference portion and AC coupling in the control loop enables the loop to respond to any transition in the one color difference signal between chroma reference times and no chroma times. Any such transitions are used to correct the hue setting of the receiver.
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