TRACK ZERO DETECTING DEVICE FOR MAGNETIC DISK RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE:To decrease adjustment man-hours and to reduce the circuit cost for drive by using the output signal of a seek detecting part which detects that the outer circumferential shifts are carried out continuously by the frequency larger than the number of tracks as a track zero signal. CONSTITUTION:When calibration is performed while a head carriage is kept at a position other than the most outer circumferential track zero point, a head carriage is moved toward the outer circumference in response to a step signal B and the count value of a counter 15 is increased. Then the carriage hits a stopper 14 when it is shifted by a degree equivalent to a certain number of steps and never moves further toward the outer circumference. When the counter 15 outputs a carry signal, a flip-flop 16 is set and a track zero signal A is not outputted yet as long as a phase detecting circuit 12 does not detect a specific phase. Then the signal A is outputted when the specific phase is obtained with input of the signal B. Then the output of the step signals outputted from a controller is stopped to complete the calibration.