METHOD FOR CORRECTING TIME AXIS

摘要

PURPOSE:To attain ease of calculation of time axis fluctuation and to miniaturize a device by using a signal having a waveform where a part of amplitude of a reference signal is changed in proportion to time as a time axis reference signal inserted in a video signal at the recording side. CONSTITUTION:The leading edge of a synchronizing signal SYN included in the video signal is detected and a burst signal BST of sawtooth wave is inserted after a fixed time from this point of time. A point crossing a level of a prescribed value a0 in one period of the burst signal is detected by using three sampling values a1-a3. The difference between the sampling values and a prescribed value is checked sequentially and reset is applied when the difference is negative at the sampling value a3, and a time tx of zero cross point is obtained by using the two sampling values a1, a2 before the a3. The extent of time axis correction is obtained from the shift tx.