Selectable rate sync generator system

摘要

A selectable rate sync generator system for use with a television test pattern generator includes a master oscillator of predetermined frequency, selector switches for selecting the desired total horizontal line time, and a horizontal line trigger circuit for generating a train of clock pulses having twice the repetition rate (2H) of the line time selected. H rate blanking and drive pulses are generated in response to the clock pulses. Selector switches are provided for selecting a desired number of horizontal scanning lines in two fields, and a vertical trigger circuit generates vertical trigger pulses having the repetition rate (V) of the number of lines selected. V rate blanking and drive pulses are generated in a response to the V trigger pulses, and the H and V rate blanking pulses are summed to provide a composite blanking signal. H rate sync pulses are generated in a response to the clock pulses and are delayed therefrom by a predetermined interval. V rate sync pulses are generated in a response to the V rate blanking pulses, and the H and V sync pulses are summed to provide a composite sync signal.