Patent ID: 7161884

Claim:
An information disc recording/playback apparatus capable of recording or playing an information disc on which information recording tracks are formed spirally or concentrically said apparatus comprising: a disc rotation means for rotating the information disc at a predetermined speed; a reading means for reading an information signal from the information disc; a drive means for driving said reading means in the direction of the radius of the information disc; a track cross detection means for generating track cross pulses on the basis of playback signals that are generated when said reading means crosses the information recording, tracks; a variable filter means for preventing counting of pulses whose widths are narrower than a set value, among the track cross pulses generated by said track cross detection means; a count means for counting the pulses outputted from said variable filter means; and a control means for determining a maximum rotation speed that is lower than an allowable number of track crosses of said information disc recording/playback apparatus on the basis of the count, or determining a maximum rotation speed that is lower than an allowable track cross speed or track cross acceleration of said information disc recording/playback apparatus on the basis of the count and the current disc rotation speed, and controlling said disc rotation means so that said disc rotation means rotates the information disc at a speed lower than the allowable maximum rotation speed to record or reproduce data in/from the information disc, wherein said control means does not use the counts obtained before a change in the value of said variable filter means if the set value of said variable filter means which is reconfigured by repetition at the same rotation speed of the information disc, is changed by a predetermined value or more when calculating the track cross count.