| 摘要 |
PURPOSE:To retrieve stably a desired track at a high speed by phase-comparing the output signal of a converting means with that of a frequency generating means. CONSTITUTION:When the 2nd moving means shifts at a high speed the scanning position of the converting means in the direction practically vertical with respect to the track direction of a recording carrier by including the 1st moving means, an address area or sector separator area is previously stored in a memory means 91. When the signal controls a switch means 83, said means disconnects the output signal of the converting means for crossing a track inputted to a phase comparing means 84 in the address area or the sector separator area. When the input signal disappears, the phase comparing means 84 phase-compares by the output signal of the converting means inputted through an immediately before the switch means 83 and the phase comparing means. Corresponding to the phase error signal, a frequency generating means 86 is caused to control frequency, and the output signal of the frequency generating means 86 is counted by a counting means with said output signal as a track crossing signal.
|
