| 摘要 |
PURPOSE: An apparatus for detecting a tilt of an optical disc is provided to detect the tilt without forming a complementary allocated pit address region in the optical disc. CONSTITUTION: An apparatus for detecting a tilt of an optical disc includes the first and second filters, a multiplier, and a low pass filter. The first filter receives a push-pull signal, which corresponds to the difference between the left and right radiation intensities of reflected lights of an optical disc constructed in a manner that the frequency of a track is different from the frequency of data and the frequency of drive servo, to selectively detect only the frequency band of the track. The second filter receives a sum signal corresponding to the sum of the reflected lights of the optical disc to selectively detect only the frequency band of the track. The multiplier multiplies the output signal of the first filter by the output signal of the second filter to generate a frequency signal including a tilting direction and tilting degree of the disc. The low pass filter eliminates the frequency component from the output signal of the multiplier to output a tilt error signal including the tilting direction and tilting degree of the disc.
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