| 摘要 |
PURPOSE: An apparatus for reading from and/or writing to an optical recording media is provided to exhibit the best possible compensation of the error in the track error signal and in the tracking signal, the error being caused on account of the lens movement CONSTITUTION: A tracking device(13) has an objective lens(3) and a vernier drive(6). The vernier drive(6) is driven by the tracking regulator(17), at whose input the track error signal DPD-TE output by a phase detector(14) is present. On the other hand, an interference signal(S) is applied to the vernier drive(6) by an interference signal generating device(22). The interference signal(S) is phase-shifted to form the signal WSY by means of a phase shifter(23) and fed to a control device(24). The control device(24) evaluates the signal WSY and the track error signal DPD-TE and sets the delay times(tau S,tau T,tau x,tau Y) of the variable delay elements(26S,26T,26X,26Y) via switching devices(25,37). The variable analog delay elements(26X,26Y) delay the signals output by the detector elements A and B and respectively C and D of the four-quadrant detector(5) by the respectively set delay times(tau X,tau Y). The signals of the detector elements(A,C), one of which is delayed, are summed at a first summation point(15) and forwarded to the phase detector(14). The same applies correspondingly to the summation point(16) and the signals of the detector elements(B,D), one of which is likewise delayed.
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