| 摘要 |
PURPOSE:To control easily the pitch of a reproduction signal by changing the speed of a recording medium and producing a master clock from the reproduction signal. CONSTITUTION:A frequency control servo circuit 15 of a drive control circuit 14 is controlled by a speed changing circuit 19. Thus the revolving speed of a disk 1 is changed as desired, and the frequency of a digital reproduction signal obtained by a pickup 2 is changed. Then a reproduction digital signal passing through a PLL7 is selected via a selector 10 of a clock generating circuit 6, and a master clock is produced from a various clock generating circuit 9 and synchronously with the reproduction digital signal. This master clock controls a demodulating/decoding circuit 4 and a D/A converting circuit 5, and a reproduction analog signal having the corresponding pitch. In such a way, the desired pitch control of the reproduction analog signal is executed simply. |
