| 摘要 |
With an optical playback device, for example, with a compact disk player, care should be taken to see that the light beam scanning the data radiates as perpendicular as possible onto the disk. However, as a consequence of disk slap or chattering, the radial and the tangential angles alter during every revolution of the disk. As a result of the tolerances in the disk and the device, the optical axis deviates from the perpendicular in many cases. In order to regulate the radial angle phi R and the tangential angle phi T, under which the light beam strikes the disk, the data signal is demodulated in an amplitude demodulator. The regulating signal UR=C* sin phi * cos alpha for the radial angle phi R and the regulating signal UT=-C* cos phi * sin alpha for the tangential angle phi T are generated from the amplitude C and the phase position phi of the demodulated data signal.
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