| 摘要 |
PURPOSE:To increase the accuracy for the rotating speed of disc and the control of rotating position, by providing equal interval marks at the circumference of a disc, producing the phase comparison pulse through the detection of the mark and performing the rotating drive control of motor so that the pulse is in agreement with the reference pulse in phase. CONSTITUTION:At the external circumference of the disc 12 turned with the DC motor 11, the marks 13 made of magnetic strips, for example, are located with equal interval. The mark detection pulse of the mark detector 14 and the reference pulse are fed to the phase comparator 15. The output of the phase comparator 15 enters the motor 11 via LPF16 and DC amplifier 17, and the rotating speed of the motor 11 can be controlled so that the mark detection pulse is in phase synchronism with the reference pulse. In this case, when the rotation reference position of the disc 12 and the position of the reference mark are corresponded in advance, the rotation reference positon of the disc 12 and the mark detection pulse, accordingly the correspondence with the phase of the reference pulse can be made. Thus, the control accuracy of disc can be increased. |
