Field to field vertical panning system

摘要

A television apparatus includes a display for a video signal representing a picture. The video signal has a vertical synchronizing component defining fields of horizontal lines which can have other than a standard number of horizontal lines per field under certain operating conditions. A counter measures the number of horizontal lines in each field. A panning circuit generates a vertical reset signal which is phase shifted by a selected number of horizontal lines relative to the vertical synchronizing component of the video signal for vertically panning the picture on the video display by the selected number of horizontal lines. The selected number of horizontal lines is adjusted responsive to the measured lengths of the fields to maintain the selected amount of vertical panning even under the certain operating conditions.