| 摘要 |
<p>PURPOSE:To shorten the locking time of tracking by detecting the entry to a dead band and outputting a detection signal and adding it to a tracking error signal as a kick pulse. CONSTITUTION:When a tracking error signal generating means 45 enters the dead band of a tracking, a regenerative signal envelope detection circuit 48 detects that the regenerative signal 27 of a head amplifier 26 has a low level. Moreover, an error detection circuit 49 detects that the regenerative signal 27 has much error, and both are ANDed to allow a dead band detection means 46 to output a detection signal 47, which is inputted to an adder 53. Then the signal is fed to a tracking error signal 41 from the tracking error signal generating means 45, a new tracking error signal 54 is generated and a SYNC detection circuit 31 detects a SYNC. Thus, the pulling-in time of the tracking is shortened.</p> |
