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Tracking error detecting device

A tracking error and detection device technology, applied in the configuration/installation of the head, instrument, data recording, etc., can solve the problems of tracking error signal accuracy deterioration

Inactive Publication Date: 2004-10-20
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0031] Then, using this phase comparison result, the phase comparison output generated by the data updating section 3 of the phase difference detection circuit 107 becomes to have Figure 14 The large value of the phase difference signal shown in the phase comparison output of , as a result, the accuracy of the tracking error signal generated by band limiting by the LPF 108 deteriorates

Method used

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Experimental program
Comparison scheme
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Embodiment 1

[0066] Below, use Figure 1, figure 2 The tracking error detecting device according to Embodiment 1 of the present invention will be described.

[0067] FIG. 1 is a block diagram showing an example of the configuration of a tracking error detection device according to Embodiment 1 of the present invention.

[0068] In Fig. 1, the tracking error detection device based on the present invention consists of a photodetector 101, current-to-voltage converters 102a-102d, two first and second adders 103a, 103b as signal generators for generating signal sequences, a first And the second analog-to-digital converter (ADC) 104a, 104b, the first and the second interpolation filter 105a, 105b, the first and the second zero-cross point detection circuit 106a, 106b, the phase difference detection circuit 11, and the low-pass A filter (LPF) 108 is formed. In addition, each constituent element other than the phase difference detection circuit 11 of the tracking error detection device accordin...

Embodiment 2

[0085] Next, a tracking error detecting device according to Embodiment 2 of the present invention will be described.

[0086] Fig. 4 is a block diagram showing an example of the configuration of a tracking error detection device according to Embodiment 2 of the present invention.

[0087] In Fig. 4, the tracking error detection device of the present invention consists of a photodetector 101, current-voltage converters 102a-102d, the first and the second adders 103a, 103b, the first and the second analog-to-digital converter (ADC) 104a, 104b, edge detection circuit 21, the first and the second interpolation filter 105a, 105b, the first and the second zero-cross point detection circuit 106a, 106b, phase difference detection circuit 22, and low-pass filter (LPF) 108 constitute . In addition, each constituent element other than the edge detection circuit 21 and the phase difference detection circuit 22 of the tracking error detection device according to Embodiment 2 of the presen...

Embodiment 3

[0106] Next, a tracking error detecting device according to Embodiment 3 of the present invention will be described.

[0107] Figure 7 It is a block diagram showing an example of the configuration of a tracking error detection device according to Embodiment 3 of the present invention.

[0108] Figure 7 Among them, the tracking error detection device of the present invention includes: a photodetector 101, equipped with a photosensitive element of reflected light of a photosensitive spot, and outputs a photocurrent corresponding to the light-sensing amount of each photosensitive element; the first to fourth current-voltage converters 102a ~102d, convert the photocurrent output of the photodetector 101 into a voltage signal; the first to fourth analog-to-digital converters (ADC) 104a~104d, according to the voltage obtained by the first to fourth current-voltage converters 102a~102d signal to obtain the first to fourth digital signal sequences; the first to fourth interpolatio...

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Abstract

A tracking error detection apparatus comprises a photodetector comprising plural photoreceptor elements; zerocross detection circuits for detecting zerocross points at which two sequences of digital signals intersect the center levels of the respective digital signals, which digital signals are generated according to the amounts of light received by the respective photoreceptor elements and are outputted from the photodetector; a phase difference detection circuit for performing phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputting a result of phase comparison; and a low-pass filter for performing band restriction to a signal outputted from the phase difference detection circuit, thereby to obtain a tracking error detection apparatus. When a phase difference between the two sequences of digital signals, which is detected by the phase difference detection circuit, is larger than a maximum value of a theoretical tracking error signal, the output from the phase difference detection circuit is limited.

Description

technical field [0001] The present invention relates to a tracking error detection device for detecting a tracking error of a light spot obtained by irradiating light onto an optical recording medium. Background technique [0002] As a method of obtaining a tracking control signal from an optical disc in which information is recorded with concave-convex pits represented by CD (Compact Disc) or DVD (Digital Video Disc), a method called a phase difference method has been used in recent years. [0003] An example of such a phase difference method is disclosed in Patent Document 1. [0004] Below, use Figure 10 The conventional tracking error detection device shown in Patent Document 1 will be described. [0005] Figure 10 is a block diagram showing the configuration of a conventional tracking error detection device. [0006] Such as Figure 10 As shown, the existing tracking error detection device has: a photodetector 101, equipped with a photosensitive element of reflected...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/00G11B7/09
CPCG11B7/0906G11B7/09
Inventor 平塚隆繁
Owner PANASONIC CORP