Patent ID: 7920349

Claim:
A phase adjusting device comprising: a rotation drive controlling unit that drives a magnetic storage medium for rotation, the magnetic storage medium having a plurality of magnetic dots disposed along a down-track direction in a magnetically separated manner and phase-detecting dots and blank bits alternately disposed along a phase-adjusting track provided between adjacent lines of the magnetic dots in a cross-track direction to provide a predetermined phase difference in the down-track direction; a magnetic-head drive controlling unit that adjusts and controls a write timing and a reproduction timing of a magnetic head unit with respect to the magnetic dots of the magnetic storage medium; a position-information managing unit that manages position information of the phase-detecting dots in the phase-adjusting track; a write controlling unit that, upon detecting a phase-detection start signal, starts writing of phase detection data by repeatedly reversing a magnetizing direction with a predetermined period of dot counts on the phase-adjusting track via the magnetic head unit and manages a write start position thereof; a reproduction controlling unit that, after the phase detection data is written, reproduces and outputs the phase detection data written in the phase-detecting dots on the phase-adjusting track in accordance with a reproduction timing of the magnetic head unit at the write start position; a reproduction-output-waveform obtaining unit that obtains a reproduction output waveform of the phase detection data written in the phase-detecting dots on the phase-adjusting track reproduced and output by the reproduction controlling unit; a maximum-output-pattern detecting unit that detects an output pattern with a maximum peak at a minus side and a plus side of the reproduction output waveform obtained by the reproduction-output-waveform obtaining unit; a zero-cross-position detecting unit that detects a zero-cross position regarding the output pattern of the maximum peak detected by the maximum-output-pattern detecting unit; and an optimum-phase-adjustment-amount determining unit that determines an optimum phase-adjusting amount for matching a phase of the write timing of the magnetic head unit with respect to the magnetic dots of the magnetic storage medium based on the zero-cross position detected by the zero-cross-position detecting unit and the position information of the phase-detecting dots managed by the position-information managing unit.