| 摘要 |
PURPOSE:To realize high density recording by eliminating the need for a potentiometer for detecting a head position by separating a control signal from a regenerative signal, obtaining a reference signal in proportion to the head position in the diameter direction of a disk based on the control signal, and rotating the disk while keeping the linear velocity of the disk constant. CONSTITUTION:A signal is regenerated by performing the track scan of the head 2 by rotating the disk 1 with a motor 5, and a pilot signal fp3 is separated from the regenerative signal by using a separation circuit 11. Next, the signal fp3 is counted by a counter 12, and supplied to a ROM 17, and a command signal to instruct a ratio to be frequency-divided is sent sequentially from the ROM 17 to a programmable frequency division circuit 16 corresponding to the number of counts. The frequency division circuit 16 performs the frequency division of a constant frequency of a reference signal generation circuit 15, and a signal of frequency inversely proportional to the number of counts is sent out, meanwhile, the signal corresponding to the rotational speed of the motor 3 can be obtained from a signal generation circuit 8, and both signals are compared with each other at a sample-hold circuit 9, and control so as to synchronize the rotation of the motor 3 with the signal obtained from a synchronous signal generation circuit 14 is applied. |
