JPS57190488A - Time base compensating device - Google Patents

Abstract

PURPOSE:To stabilize an operation against disturbance, etc. without deteriorating its accuracy when correcting at the write side, by shifting in order a period corresponding to a prescribed period of a clock pulse, and executing each compensation in said prescribed period. CONSTITUTION:A composite video signal S1 from an input terminal 1 is converted to a digital signal by an A/D converter 4, and is written in a memory 6. A clock pulse applied to this converter 4, and a clock pulse applied to a memory controlling circuit 7 for controlling the memory 6 are synchronized with a horizontal synchronizing signal of the signal S1 and a burst signal. By a synchronization separating circuit 9 for inputting this signal S1, the horizontal synchronizing signal is separated, the burst signal is extracted by a burst gate 10, frequency of 4 times of a subcarrier is generated from a VCO13, and a pulse of 4 phase is outputted from a 4-phase pulse generating circuit 17. Subsequently, a period corresponding to 4 periods of the pulse is shifted in order, correction is executed at the writing side to the memory 6 in 4 periods, and the operation is stabilized against disturbance, etc. without deteriorating its accuracy.