TV circuit with vertical scanning pulses - which are produced from synchronising pulse train, evaluating increase in forward equalisation frequency w.r.t. line frequency

摘要

The TV circuit is used to produce vertical scanning pulses from the synchronising pulse sequence. The signal is used to mark the start of a half image. The pulse is used to synchronise the vertical deflection when reproducing the image. It derives a first pulse by evaluating the increased frequency of the forward equalisation pulse relative to the line frequency. A second pulse relative to the vertical synchronization pulse is derived and the pulse width evaluated. The pulse is supplied to an AND stage (5) where the output (7) is used as a scanning pulse. (DS).