| 摘要 |
A tracking circuit is disclosed for a recording and/or playback machine that scans a recording medium without contact. The tracking circuit of a CD-player is provided for example with a coarse drive (M2, SP) on which is mounted a fine drive. In order to be able to guide the data-scanning light beam (L) along the data tracks of the disk (CD), the coarse drive (M2) is switched on from time to time. The coarse drive generates mechanical vibrations, however, which can cause track loss or even focus loss, if at the same time defects are found on the CD, for example scratches or fingerprints. In order to increase the scanning reliability, the track error signal (TE) or the focus error signal (FE) is checked for errors by a detector (H1), for example. As long as the detector (H1) indicates an error, the coarse drive (M2) remains switched off.
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