Method and circuit for compensating slow-varying runout of disk storage system

A circuit for compensating a slow-varying runout of a disk storage system, suitable for a disk storage system employing a disk as information storage medium, wherein the disk storage system reads data from the disk or writes data into the disk by means of a pickup head and the pickup head is able to output a position signal (PS), comprising:

• a computation device, used for computing a position error signal (PE signal) according to the PS, the specified pickup head position and a compensation displacement;
• a filter, used for filtering the PE signal to obtain a runout error signal (RE signal);
• a waveform generator, used for deciding a basic runout compensation signal (BRC signal) for output according to a received first control signal;
• an amplifier, coupled to the waveform generator and used for deciding an amplification coefficient of the BRC signal according to a received second control signal and for outputting a runout compensation signal (RC signal);
• a phase-difference detector, coupled to the waveform generator and the filter to receive the BRC signal and the RE signal and used for comparing the phase-difference between the BRC signal and the RE signal and for deciding the first control signal for output according to the comparison result;
• an amplitude-difference detector, coupled to the waveform generator and the filter to receive the BRC signal and the RE signal and used for comparing the phase-difference between the BRC signal and the RE signal to identify whether the BRC signal is in-phase of the RE signal or in-inverse-phase of the RE signal and for deciding the second control signal for output according to the comparison result;
• a controller, used for deciding a compensation signal (CS) for output according to the PE signal;
• and
• a compensation servo, used for deciding a compensation displacement of the pickup head according to the CS and the RC signal.

A method for compensating a slow-varying runout of a disk storage system, suitable for a disk storage system employing a disk as information storage medium, wherein the disk storage system reads data from the disk or writes data into the disk by means of a pickup head and the pickup head is able to output a position signal (PS), comprising:

• generating a basic runout compensation signal (BRC signal);
• according to the PS generating a runout error signal (RE signal);
• comparing phase-difference between the BRC signal and the RE signal for deciding whether the BRC signal phase needs to be adjusted according to the comparison result;
• and
• using a runout compensation signal (RC signal) obtained by adjusting the BRC signal for further adjusting the pickup head.

A method for compensating a slow-varying runout of a disk storage system, suitable for a disk storage system employing a disk as information storage medium, wherein the disk storage system reads data from the disk or writes data into the disk by means of a pickup head and the pickup head is able to output a position signal (PS), comprising:

• generating a basic runout compensation signal (BRC signal);
• according to the PS generating a runout error signal (RE signal);
• comparing the BRC signal with the RE signal for deciding whether the BRC signal is in-phase or in-inverse-phase of the RE signal and for deciding whether the BRC amplitude needs to be adjusted according to the comparison result;
• and
• using a runout compensation signal (RC signal) after adjusting the BRC signal for further adjusting the pickup head position.