| 摘要 |
The present invention discloses a method for controlling the position of a radiation beam on an optical carrier (1), e.g. a CD, a DVD, a HD-DVD or a BD disc, in an optical drive. Initially, the optical pickup unit (OPU) is fixated relative to the optical carrier and there is established a closed-loop control - so-called capture - in response to an error signal e.g. radial or focus error tracking signal (FE, RE). Then, by servo control means (9, 50) a first bandwidth (BWl) is set in a stabilization period (SP), and subsequently a second bandwidth (B W2) of the servo control means is set. The second bandwidth (B W2) is lower than the first bandwidth (BWl). The invention applies bandwidth switching and thereby provides a more robust operation of the optical drive, as the first and second bandwidths may be separately optimised. Additionally, the power consumption of the optical pickup unit (OPU) may be reduced.
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