| 摘要 |
<p>PURPOSE:To attain the detection of shifts among a rotor, a tachometer and a disc by detecting an error depending on the relation of time between the detection of a center position of a servo signal and of an index signal. CONSTITUTION:A prescribed level or over of a reading signal from a magnetic tape 8 via an amplifier 13 is detected, a 2f detecting circuit 14 is activated, the detection of a center point of a servo signal is latched to the circuit 14 and a counter 17 starts the count of a clock A. This counter 17 continues counts until it is reset by an output of a rotor/tachometer detecting circuit 16 corresponding to the turning-off of the strip index signal normally and accesses an ROM 18 of a time decoder. When a time relation output from the ROM 18 and an ON-signal of the circuit 16 are ANDed by a timer check circuit 19, a signal B representing a failure is generated from the circuit 19 and the detection of unmatching of slits between the rotor and tachometer is attained after adjustment.</p> |
