| 摘要 |
<p>PURPOSE:To control speed so that deviation data are minimized and to speed up program searching by calculating deviation data based on the number of generated errors in ID data and forming a tracking servo correcting signal. CONSTITUTION:A reproduced signal in each tracking period is supplied to a PCM demodulating circuit 8, ID data written in each ID word recording part and obtained error pulse EP are respectively sent to counters 9. While being reset at every unit time, each counter counts up error pulses, so that the number of times generating errors at every unit time can be counted in each ID data. The count values of respective counters 9 are sent to a comparator 10 and a tracking servo correcting signal X corresponding to the deviation of distribution of respective count values is formed and sent to an adder 24. Thus, the speed control of the tracking servo can be executed so that the deviation data are minimized.</p> |
