| 摘要 |
<p>PURPOSE:To shorten the lead-in time for tracking control by using reference signals with the two same frequencies among four types of pilot signals at the different timing when tracking control and its abnormality are detected. CONSTITUTION:The reference signal at the time of reproduction is switched to f1 f3 f1 f3 f1... through a switch circuit 17 according to a signal at 15Hz obtained by frequency-dividing a head switching signal at 30Hz by means of a frequency dividing circuit 20. While a head HA is tracking on a tape, the output of a level comparator circuit 10 is supplied to a tracking control circuit 35 through a switch 22. Whereas a head HB is tracking on the tape, a switch 23 is turned on and the output is supplied as a tracking control abnormality detection signal to a level comparator circuit 25. When its outputs drops below a reference voltage Vref, a switch control circuit 19 operates to invert the generation phase of the reference signal. Thus the operation can be moved to a tracking control lead-in state from a tracking control abnormal state.</p> |
