Tracking error signal generation circuit

Abstract

Abstract PURPOSE:To obtain the uniform tracking error signals which are free from the effect of the pit depth of a disk by adding with weighting the tracking error signals obtained from outputs of plural main signal detecting parts and subsignal detecting parts. CONSTITUTION:The reflected light of a main beam and two sub-beams projected to a disk are received by a four-section main detection part 21 set at the center of a pit train and subdetection parts 22 and 23 set symmetrically at both sides of the part 21. The output signals of photodetecting areas PDb and PDd as well as PDa and PDc of the part 21 are added together by arithmetic circuits 24 and 25 respectively. This sum signal undergoes subtraction through a subtractor circuit 26, and a tracking error signal TE1 is obtained. While output signals of parts 22 and 23 undergo subtraction through a subtractor circuit 27 to obtain a tracking error signal TE2. Both signals TE1 and TE2 undergo a prescribed weighted addition through an arithmetic circuit 28 and are delivered through an output terminal 29. In such a way, the uniform tracking error signals are obtained with no effect of the pit depth.

Inventors

• 👤 Yasuhiro Hayashi
• 👤 泰弘 林

Bibliographic Details