Tracking control circuit

Abstract

Abstract PURPOSE:To prevent the malfunction of tracking control by obtaining the offset of a tracking error signal due to skew and adding an offset compensating signal based on this offset to the output of a photosensor. CONSTITUTION:A photosensor output T is given by T=alphaI (alpha is a proportional constant) where I is the intensity of beam on the photosensor. When the skew angle in the radial direction of a disk is theta and the beam is displaced on a photosensor S by DELTA, the intensities of beam on two-divided photosensor S1 and S2 are obtained based on the formula of Gauss distribution intensity in a three-dimensional space. Since the offset of the tracking error signal occurs between outputs T1 and T2 of two-divided photosensors, the compensating signal which cancels this tracking offset DELTARE is applied to the outputs T1 and T2 of photosensors S1 and S2.

Inventors

• 👤 Shoichi Yoshii
• 👤 正一 吉居

Bibliographic Details