Phase error detecting apparatus

Abstract

A phase error determining apparatus that can perform a precise offset correction of a tracking error signal even if any defects or any positions unused for recording exist on an optical disc. Both a phase difference determining circuit (107), which receives digital signals of two systems and uses the distance between the zero-crossing points of the digital signals of the two systems to perform a phase comparison and output a phase comparison result (PCR) and a phase comparison completion signal (PCC), and an offset gate circuit (11), which outputs an offset correction amount for each phase comparison completion signal (PCC) from the phase difference determining circuit (107), are used to add an offset correction amount (a) to the phase comparison result (PCR), thereby inhibiting any offset corrections from being done at any positions where no phase comparisons are performed.

Description

technical field [0001] The present invention relates to a phase error detection device for detecting a tracking error signal of a light spot obtained by irradiating light onto an optical recording medium. Background technique [0002] As a method of acquiring tracking control signals from optical discs such as CD (Compact Disc) and DVD (Digital Versatile Disc) in which information is recorded with concave and convex pits, a method called phase difference method has been used in recent years. [0003] As an example of the relevant phase difference method, there is a method disclosed in Patent Document 1. [0004] Below, use Figure 30 A conventional phase error detection device 3010 disclosed in related Patent Document 1 will be described. [0005] Figure 30 It is a block diagram showing the configuration of a conventional phase error detection device 3010 . [0006] Such as Figure 30 As shown, the conventional phase error detection device 3010 includes: photosensitive el...

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Problems solved by technology

[0031] However, in the conventional method of correcting the DC offset amount of the tracking error signal, the offset correction amount is added even when there is no input signal and no phase difference is detected at a defective position or an unrecorded position, etc. When there is no signal, the offset voltage is output, and the tracking servo becomes unstable, etc.

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