Wobble signal demodulating circuit and optical disc
A technology of signal demodulation and optical disc device, which is applied in the direction of signal processing, information storage, and optical recording system using self-timed codes, and can solve the problems of lower allowable value, lower recording quality, and inability to correctly obtain address information, etc.
Inactive Publication Date: 2006-09-13
RICOH KK
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Problems solved by technology
In the future, if the recording speed is increased, the causes of noise will be diversified, and at the same time, the allowable value of the noise level will be reduced. It is conceivable that due to the dispersion of the quality of the signal demodulated by the phase, the situation that the address information cannot be accurately obtained, resulting in RISKS OF RECORDING QUALITY
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Embodiment Construction
[0042] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an optical disc device according to an embodiment of the present invention.
[0043] The optical disc device 20 shown in Figure 1 has: a spindle motor 22 for rotationally driving the optical disc 15, an optical pickup device 23, a laser control circuit 24, an encoder 25, a motor driver 27, a reproduction signal processing circuit 28, and a servo controller 33 , buffer RAM34, buffer manager 37, interface 38, flash memory 39, CPU40 and RAM41, etc. Furthermore, the connecting lines in FIG. 1 represent typical signals and flows of information, and do not represent the connection relationship of all blocks. Furthermore, in this embodiment, as an example, an information recording medium conforming to the DVD+R standard is used for the optical disc 15 .
[0044] On the recording surface of the optical disc 15, a groove (referred...
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Abstract
A wobble signal demodulating circuit performing phase demodulation of a wobble signal being acquired based on a reflected light from the recording surface of an optical disc provided with a snaking track and including a carrier part having a specified basic frequency and a phase modulated wave part added with specified information, comprising a band-pass filter having a central frequency in the vicinity of the basic frequency and extracting the signal of the carrier part from the wobble signal, a circuit for regulating the central frequency of the band-pass filter based on a frequency regulation signal corresponding to the line speed of rotation of the optical disc, a circuit for generating a clock signal from the extracted signal of the carrier part, and a circuit performing phase demodulation of the phase modulated wave part of the wobble signal in synchronism with the clock signal.
Description
technical field [0001] Field of the Invention The present invention relates to a wobble signal demodulation circuit and an optical disc device, and more specifically, to a wobble signal demodulation circuit for phase-demodulating a wobble signal obtained from an optical disc, and an optical disc device having the wobble signal demodulation circuit. Background technique [0002] In recent years, with the advancement of digital technology and the improvement of digital compression technology, as a medium for recording user data such as music, video, photos, and computer software, CDs (Compact Discs), and CDs that can be stored on disks with the same diameter as CDs Optical discs such as DVD (Digital Versatile Disc) which record data about 7 times that of CDs are attracting attention, and as the price becomes lower, optical disc devices using optical discs as the target medium for data recording are also popularized. [0003] In general, in write-once optical discs such as DVD+...
Claims
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IPC IPC(8): G11B7/005G11B7/0045G11B20/14G11B20/10
Inventor 管田浩一郎
Owner RICOH KK