Rotation control device for information recording medium disk

Abstract

Abstract PURPOSE:To avoid deterioration of the stability for the control loop for fixed linear speed rotation by securing the fixed control for the gain of the rotation control servo loop of the disk which performs the fixed linear speed reproduction and regardless of the radius position of the reproduction element. CONSTITUTION:The monomulti MM of frequency discriminator circuit FD is triggered by the driving motor rotation detection pulse of the disk or the like, and then the frequency discrimination signal voltage is applied to amplifier MDA in correspondence to the different numbers of rotation according to the radius position of the disk or the like of the reproduction element. Thus the servo control is given to the rotation number of the motor to secure the fixed linear speed reproduction according to the position of the reproduction element. At the same time, the frequency discrimination signal is applied to limiter signal generator circuit LVS of circuit FD to give the control to the limit voltage of gain control part GS which forms the motor rotation control servo loop along with phase comparator PC which gives a control between the reproduction synchronous signal and the reference signal in accordance with the position of the reproduction element, servo amplifier SA and others. As a result, the gain of control part GC becomes constant regardless of the radius position of the reproduction element, thus preventing the deterioration of stability for the fixed linear speed rotation control loop.

Inventors

• 👤 Yasuo Hachi

Bibliographic Details