Patent ID: 7215621
Filing Date: 2007-05-08
Classification: G11B

Abstract:
1. An information disc recording/playback apparatus capable of recording or playing at least two kinds of information discs having different track pitches, 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 pitch detection means for detecting the track pitch of the information disc from the information disc; a track cross detection means for generating track cross signals on the basis of playback signals that are generated when said reading means crosses the information recording tracks; a track cross direction detection means for detecting a track cross direction indicating the direction in which said reading means crosses the information recording tracks; a rotation angle detection means for outputting rotation angle information of said disc rotation means, the rotation angle information being divided into n areas for one rotation, wherein n is a natural number; a zero cross area detection means for detecting two areas where the track cross speed has a lowest value, from among the n areas; a count means for counting track cross pulses which are detected by said track cross detection means, on the basis of the result of the detection by said track cross direction detection means and the rotation angle information outputted from said rotation angle detection means, and for outputting the count; and a control means for in an area where the track cross speed has the lowest value according to the result of the detection by said zero cross area detection means, said track cross direction detection means detects the track cross direction, and said count means adds signs to the track cross pulses and counts the track cross pulses having the signs added thereto, on the basis of the track cross direction detected by said track cross direction detection means; and in an area where the track cross speed does not have the lowest value according to the result of the detection by said zero cross area detection means, said track cross direction detection means does not detect the track cross direction, and said count means adds signs to the track cross pulses and counts the track cross pulses having the signs added thereto, on the basis of the track cross direction that has just previously been detected by said track cross direction detection means.