| 摘要 |
<p>PURPOSE:To perform the correct tracking control by differentiating the output signal received from a magnetic head by a differentiation circuit and using this differentiated signal to discriminate a normal signal from a miserased signal. CONSTITUTION:The output signal of a magnetic head 1 is supplied to a differentiation circuit 11 and differentiated there. Thus the differential characteristics of the head 1 are further emphasized. The normal cyclic signal has a higher level and contains many higher harmonic components and therefore the output signal of the circuit 11 has a large peak value. A peak detecting circuit 12 compares the output signal of the circuit 11 with a reference signal and delivers a positive signal, for example, when the output signal level is higher than the reference voltage V1 or lower than the reference voltage V2. A holding circuit 13 holds the output signal level of the circuit 12. The output signal of the circuit 13 is supplied to a comparator 14 and compared with the prescribed reference voltage V3.</p> |
