| 摘要 |
<p>PURPOSE:To return operation to normal tracking by comparing frame addresses in the first half and latter half of a track, and at the time of deciding the abnormality of the track, generating a pulse. CONSTITUTION:A comparator 7 compares the frame address in the first half of the track with the frame address in the latter half, and when both the frame addresses are different each other, outputs the size relation of the two frame addresses. A counter 8 counts the output of the comparator 8 every track, and after the elapse of a continuous fixed period, generates an output to a pulse generating circuit 9, which generates a pulse in a direction for making the two frame addresses coincide with each other. The pulse generated from the circuit 9 is added to an AFC error signal and a tracking error signal by an adder 10 and the added result is amplified by an MAD 3 and applied to a capstan motor 4, so that the operation can be returned to normal tracking.</p> |
