Abstract: A data for measuring deviation between a recording head and a playback head easily for correctly reproducing data despite such deviation. A playback signal amplitude detection circuit 23 detects the amplitude of playback signals of test data from a playback amplifier 15, while adders 51, 52 cumulatively sum the amplitude values of playback signals in a pre-set group of sectors and those in another pre-set sector of groups on a magnetic disc 21 supplied from the playback signal amplitude detection circuit 23. A subtractor 50 computes a difference between a first sum value from the adder 51 and a second sum value from the adder 52 and routes the difference to a controller 11. The controller detects deviation between the recording head and the playback head from the difference value. When recording or reproducing actual data, the controller 11 causes the position of the recording head or the playback head to be corrected on the basis of the detected deviation.

Abstract: A data for measuring deviation between a recording head and a playback head easily for correctly reproducing data despite such deviation. A playback signal amplitude detection circuit 23 detects the amplitude of playback signals of test data from a playback amplifier 15, while adders 51, 52 cumulatively sum the amplitude values of playback signals in a pre-set group of sectors and those in another pre-set sector of groups on a magnetic disc 21 supplied from the playback signal amplitude detection circuit 23. A subtractor 50 computes a difference between a first sum value from the adder 51 and a second sum value from the adder 52 and routes the difference to a controller 11. The controller detects deviation between the recording head and the playback head from the difference value. When recording or reproducing actual data, the controller 11 causes the position of the recording head or the playback head to be corrected on the basis of the detected deviation.

Abstract: A disc recording/reproducing apparatus includes a tracking servo system in which a recording/reproducing head is moved based upon a target position signal indicating its pre-set target position on a disc-shaped recording medium and in which the recording/reproducing head is controlled in its position by a driving unit which employs an output of a controller which is supplied with a position signal obtained by subtracting a deviation from a pre-set target position from the target position signal. The apparatus also includes an eccentricity data storage unit for storing eccentricity data indicating the tracking position of the recording/reproducing head which depends upon eccentricity of the disc-shaped recording medium. The eccentricity data from the eccentricity data storage unit is summed to the target position signal for controlling the position of the recording/reproducing head.