Deflection circuit for nonstandard signal source.

摘要

A deflection circuit for a video apparatus operates in a countdown mode in which synchronization of the vertical deflection circuitry is accomplished in precise relationship to the horizontal deflection frequency. In order to permit countdown operation for nonstandard but stable signal sources, such as video games, the countdown mode acceptance window is determined in a manner to encompass the coincidence of vertical sync pulses from signal sources having horizontal line per field ratios that may differ from the broadcast standard.