Patent ID: 6614745
Filing Date: 2003-09-02
Classification: G11B

Abstract:
A recording apparatus for recording data on a disk-shaped recording medium whose signal recording surface is provided with a land and a groove as a recording track, in which a wobble is formed between the land and the groove, and has a superimposed waveform of a first frequency waveform and a second frequency waveform which is lower than first frequency, the recording apparatus comprising:drive means for rotatively driving the recording medium; light irradiation means for condensing and irradiating a laser beam onto a target track and both tracks adjacent to the target track on a signal recording surface of the recording medium rotatively driven by the drive means; light detection means for detecting a return light from each of the target track and both tracks adjacent to the target track and converting the return light to an electric signal; high-pass filtering means for filtering a high-frequency component in a signal corresponding to a return light output by the light detection means from the target track; low-pass filtering means for filtering a low-frequency component in a signal corresponding to a return light output by the light detection means from each of the both tracks adjacent to the target track; arithmetic means for computing a signal passing the high-pass filtering means and a signal passing the low-pass filtering means, the arithmetic means nullifying a nonlinear component due to wobbles of both tracks adjacent to the target track and extracting the first frequency waveform component; and means for generating a reference signal based on a phase of a signal computed by the arithmetic means.