Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Kazutoshi Aida

Toshihiko Takahashi

Youichi Ogura

Ryusuke Horibe

Kouji Okamoto

Masaharu Imura

Ryuusuke Horibe

The present invention is aimed at providing an optical disc device and a recording condition setting method which can automatically determine an optical recording condition to an optical disc, and the optical disc device comprises an optical pickup which records data on a disc; a data encoder which modulates data to be recorded; a recording timing setting means which sets a timing of recording the data on the disc; a phase error detection means which measures an error amount of a mark recorded on the disc from a position where the mark should be properly located; an error convergence means which calculates error information indicating an optimum position of the mark; a recording timing calculation means which calculates a correction value of the recording timing to be set on the recording timing setting means, based on the error information; and a control means which feedbacks an output of the recording timing calculation means to the recording timing setting means, thereby to optimize the recording timing.

Optical disc device and recording condition setting method

A variable gain amplifier (: VGA) for amplifying an amplitude of a signal extracted by a pickup (), an A/D converter () for converting the amplified signal into digital, and an amplitude detecting circuit () for detecting amplitude information from the digital information, are provided. A gain control circuit () for calculating a control value for the VGA () is calculated from the detected amplitude information, and an envelope generating circuit () for executing an operation of absorbing transfer characteristics of the VGA () from the control value for the VGA () and the amplitude information, are provided to generate an envelope extracted by the pickup (). When the characteristics of the VGA () vary, a degree of the variation is calculated from the amplitude information of the signal extracted by the pickup () and amplitude information obtained by fixing the control value for the VGA (), and characteristic correction is executed.

Optical disc apparatus

When generating a sampling clock of an A/D converter for digitizing a playback signal from an optical disc, an over sampling clock generated by a PLL is used. Further, zerocross position information and reference information of a playback digital signal that is obtained by A/D conversion using the over sampling clock are converted into those synchronized with the channel bit clock by an operation cycle conversion unit, and then supplied to a PRML signal processing unit and a level judgement binarization unit.

Playback signal processing apparatus and optical disc device

An information reproduction apparatus and method according to the present invention are provided so as to solve the problem that signal quality is degraded in a normal signal part when always performing a correction of a transient in reproducing information recorded in a medium, and the sag cancellation controller () detects whether the pickup output signal (S) is normal or abnormal, and the sag cancellation part () performs a correction of a transient only during a period when the pickup output signal (S) is detected as abnormal, thereby preventing degradation of signal quality, which is caused by performing a correction of a transient on a normal signal part, and an appropriate correction of a transient can be performed on an abnormal signal part, thereby enabling a stable reproduced signal (S) to be obtained.

Information reproduction apparatus and information reproduction method

A feedback loop structure including an operational amplifier unit () for amplifying a reproduction signal of recorded information and a gain/offset control unit () for controlling an amplitude and an offset of an output of the operational amplifier unit () so that each of the amplitude and the offset becomes a predetermined value is adopted, and accurate information for an asymmetry amount is obtained by a binarization unit () for receiving the output of the operational amplifier unit () and performing binarization while adjusting a slice level by feedback control so that a duty ratio after the binarization substantially becomes a predetermined value. Based on the asymmetry amount information, a judgment level of a Viterbi decoding unit () is changed, thereby reducing a reproduction error rate.

Signal processing device and signal processing method

In playback of data recorded on an optical disk, an error minimization circuit holds a plurality of ideal values for partial response (PR) equalization as equalization targets, and updates tap coefficients of a finite impulse response (FIR) filter so that the errors between the outputs of the FIR filter reflecting the output of an analog-to-digital converter (ADC) and the equalization targets are minimized. An error detection circuit and an addition/weighting circuit generate a signal representing the errors between the outputs of the FIR filter and the equalization targets as a parameter signal correlated with the error rate of played-back data. The quality of the analog signal is adjusted so that the parameter signal is minimized, to thereby optimize the margin of the error rate of played-back data.

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Osaka, Japan

Kazutoshi Aida