| 摘要 |
PROBLEM TO BE SOLVED: To control the rotation of a spindle motor during tracking-off without being influenced by jitter of an RF signal. SOLUTION: During the tracking-off, a controller 21 controls an OFT (the off-track) detection On/Off circuit 20 so that the OFT signal is supplied to a hold circuit 19. When a signal generation circuit 13 detects the off-track, the signal level of the outputted OFT signal becomes an H level. The hold circuit 19 is equipped with a low-pass filter, when the signal level of the OFT signal is in the H level, which removes the RF component of the frequency signal outputted from a PLL circuit 35, and supplies only the low frequency component to a driver 17 via an LPF18. The driver 17 supplies only the held voltage to a spindle motor 11. COPYRIGHT: (C)2007,JPO&INPIT
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