Video blanking circuit with controlled rate of unblanking

摘要

A circuit is disclosed for automatically blanking the kinescope of a color television receiver during channel changing intervals. The receiver also includes an automatic kinescope beam current limiter, plural kinescope driver stages, and a source of reference bias voltage to which video signals amplified by the kinescope driver stages are normally referenced, coupled in common to the plural kinescope driver stages. During channel changing intervals, the blanking circuit modifies the reference voltage with a given blanking response time so that the driver stages and kinescope are blanked. The blanking circuit exhibits an unblanking response time, slower than the blanking response time, for permitting the reference bias voltage to gradually return to a normal level after the channel change interval ends, at which time the driver stages and kinescope are unblanked and operate normally.