| 摘要 |
PURPOSE:To make stable tracking by giving a spurious TR error signal and shifting TR when a tracking (TR) error signal is too large to detect the reference synchronous signal and holding former value when the synchronous signal is not possible to detect due to blinding of the head or drop out. CONSTITUTION:Output of head 1a, 1b is inputted to a TR error detecting circuit 6 via an amplifier 2 and through a synchronous signal detecting circuit 4 and a TR signal detecting circuit 5, and the circuit 6, on receiving a synchronous signal from the circuit 4, sample holds a TR signal from the circuit 5, and outputs a TR error signal. When the synchronous signal is not detected, specified voltage is outputted as a TR error signal when a regenerative output detecting circuit 3 detected regenerative output, and when the circuit 3 can not detect regenerative output, existing output is maintained. A capstan motor 10 forms a speed controlling loop with a frequency generator 11, a speed controlling circuit 9 and a capstan motor driving circuit 8, and controlled to make output from the circuit 6 zero.
|
