| 摘要 |
PURPOSE:To prevent off-track due to a variation of temperature by detecting a variation of crosstalk voltage based on different frequency signals from gap parts of adjacent tracks due to off-track to control positioning. CONSTITUTION:Reproduced components which pass a recording and reproducing head 30 and an analog switch 35 and are not effective data of gaps parts 1-3 and are different in frequency signal by track are separated by BPFs 37-39 and pass detectors 40-42 and are processed by differential amplifiers 46-48. A crosstalk voltage difference between gap parts of adjacent tracks which is constant for on-track is outputted as a track error voltage from a level detector 58 through analog switches 49-51. The position of a servo head 72 is servo- controlled through an up/down counter 62, a D/A converter 64, a filter 66, etc. which are operated in accordance with this error voltage. Thus, off-track due to a variation of temperature is prevented. |
