CONTROLLER OF DISK REVOLUTION

PURPOSE:To accurately control the revolution which keeps set at linear velocity at a specified level at all times, by correctioning and controlling a disk turning motor which is controlled with the pickup position signal via a potentiometer basing on the reproduced signal. CONSTITUTION:The position signal of a pickup 14 in the radial direction of a disk 12 which is produced by a potentiometer 15 is applied via a divider circuit 16, etc. to control a disk turn motor 2 so as the linear velocity of the disk 12 is kept set constant at the counter part of the pickup 14. On the other hand, an up-down deciding circuit 1 decides the speed of revolution of the disk 12 by counting bit number of the reproduced signal supplied from the disk 12 and then controls corresponding electronic switches 4 and 7 in an integration circuit 10 to produce the integration outputs having different polarities in accordance with the speed. The integration output is applied to an adder 11 to give a correction to the position output produced by the potentiometer 15. Thus the feedback control is executed to a motor 13. As a result, the accuracy is increased for the revolution control to obtain a constant linear speed at all times without affecting the meter 15, etc.