| 摘要 |
PURPOSE:To largely improve the control efficiency of a microcomputer by providing frequency dividing means for dividing the frequency of a feedback signal in response to a driving direction. CONSTITUTION:When an optical system is moved forward, a feedback signal FG1 is not divided in frequency, but the signal FG1 is output through an OR circuit 3 to a microcomputer 13 and a phase comparator 15 so that a motor 21 is controlled at its speed. When the motor 21 is moved backward, a reverse signal RV is fed from the microcomputer 13 to an AND circuit 2a. Accordingly, a feedback signal FG2 divided by a frequency divider 1 in frequency by 1/N from the signal FG1 is output through the OR circuit 3 to the microcomputer 13 and the comparator 15. Thus, the speed difference between those at forward and backward times is increased so that FG-interrupt control is started many times, and the microcomputer 13 can complete a speed control within a predetermined time. |
