| 摘要 |
A vertical panning system comprises: a source of respective signals having a vertical synchronizing frequency, a horizontal synchronizing frequency and a multiple of the horizontal synchronizing frequency; a video display having an interlaced field mode of operation; a horizontal display control circuit coupled to the video display and responsive to the supplied horizontal synchronizing frequency signal; a digital phase delay circuit, responsive to the supplied multiple horizontal synchronizing frequency signal, the supplied vertical synchronizing frequency signal and to a panning control signal, having as an output a second vertical synchronizing frequency signal delayed in phase relative to the supplied vertical synchronizing frequency signal by any one of a plurality of delays differing in increments corresponding in duration to horizontal half line intervals; and, a vertical display control circuit coupled to the video display and responsive to the second vertical synchronizing frequency signal.
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