Abstract: An optical disc reproducing apparatus includes an A/D converter; an asymmetry compensator for detecting 4T sampling signals; a phase locked loop including a frequency detector that counts and detects run-length signals from the digital signals and compensates frequency errors of the digital signals; a binary module including a Viterbi decoder, a slicer, and a minimum T compensator that compensates the digital signal with a minimum signal having a unit cycle; an equalizer; an adaptive level error detector detecting a base level of the Viterbi decoder from both an input signal into the equalizer and an output signal from the Viterbi decoder, and computing a filtering coefficient of the equalizer from the base level; and a signal quality measurer measuring a jitter or an SbER of the digital signal.

Abstract: A defect signal detecting apparatus for an optical recording/reproducing apparatus that includes a maximum value detecting unit for detecting a highest amplitude among signals input during a maximum value detection period as a maximum value, a minimum value detecting unit for detecting a lowest amplitude among signals input during a minimum value detection period as a minimum value, an asymmetry detecting unit for calculating an amount ? of asymmetry by detecting a maximum value ILmax and a minimum value ILmin of a signal IL having a maximum periodicity among the signal input, and a maximum value ISmax and a minimum value ISmin of a signal IS having a minimum periodicity among the signal input, and a defect determining unit for determining whether there is a defect in the signal input, using the maximum value, the minimum value and the amount ? of asymmetry.

Abstract: An asymmetric error correction device includes an analog-to-digital (A/D) converter sampling analog radio frequency (RF) signals reproduced from an optical disc with a sampling period, converting the same into the digital sampling signals, and outputting the same; a signal detector for detecting 4T sampling signals varying in polarity thereof every four times the sampling period among the digital sampling signals; an operator selecting and adding a signal among the 4T sampling signals to operate an asymmetric error value; a counter cumulatively counting the asymmetric error value operated in the operator; and a corrector correcting a signal level of the digital sampling signal outputted from the A/D converter if the counted value counted by the counter is out of a predetermined critical range. The asymmetric error is precisely corrected even in a signal part in which the asymmetric error is minutely generated.

Abstract: A recording and/or reproducing apparatus and method with signal quality determining device and a method thereof, with the signal quality determining device including a signal estimator determining a level corresponding to a sample value of the RF signal using binary data obtained from the RF signal and generating a selection signal corresponding to the determined level, a channel identifier classifying the sample value into a plurality of levels according to the selection signal and obtaining an average value of the sample values classified into each level, and a quality calculator outputting a signal quality value representing quality of the RF signal using each sample value output from the channel identifier and the average value of the sample values classified into each level. Accordingly, quality of an RF signal can be determined more exactly, and focus compensation, tilt compensation, detrack compensation, and recording signal optimization can be performed using the determined signal quality.

Abstract: An apparatus and method for measuring the quality of a signal on an optical disc based on level information of a viterbi decoder are provided. The signal quality measuring apparatus includes: a binary unit that generates binary signals from input RF signals; a channel identifier that receives the input RF signals and the binary signals output from the binary unit and outputs reference level values corresponding to the binary signals; and an information calculator that receives the reference level values and detects a signal quality value.

Abstract: A signal quality measuring method and apparatus in which a quality of a signal detected from an RF signal read out from a disk or a communications channel is measured by using eye pattern signals of the detected RF signals. Eye pattern signals representing time change of a waveform of the detected signal are generated and a signal quality value is generated based on an eye depth and/or an eye width measured from the eye pattern signals. A histogram of the eye pattern signals is used to identify a plurality of main level values which are used as a reference value in measuring the signal quality. Accordingly, signal characteristics in a high-density storage medium system or communication system may be accurately represented.

Abstract: A Viterbi detection apparatus and a method therefor remove code error paths generated in optical Viterbi detection. Accordingly, paths containing 1T code based on a code condition are removed even under a condition PR (a, b) by extending a radix structure to facilitate high speed operation.

Abstract: A device and method of data reproduction that can achieve a reference level optimizing the characteristic of a channel and can be applied to the reproduction of data on an optical disk are provided. According to the device and method, even when an input signal is in an abnormal state, an input level value can be initialized so that a viterbi decoder can normally operate.

Abstract: A method and apparatus for detecting signal quality, and a computer readable recording medium having embodied thereon a program to execute the method. In the method for detecting the quality of an input signal, an estimated signal is calculated from an input signal by using a predetermined filter coefficient, then the filter coefficient is updated to minimize a difference between the estimated signal and the input signal, and based on the updated filter coefficient, the quality of the input signal is calculated.

Abstract: A device and method for data reproduction of an optical disk generating an optimized reference level optimizing a channel characteristic, the device includes a channel identifier which receives an input signal of an equalizer and detects an optimum level, and an adaptation process which by using the detected optimum level, updates the coefficient of the equalizer. Accordingly, the data reproduction device and method can detect a reference level value capable of maximizing the performance of a viterbi decoder and limit noise caused by tilt and other effects that may occur by the shape of a disk or a pickup apparatus.

Abstract: A method and apparatus detecting binary data, the apparatus includes an analog-to-digital (AD) converter converting the input analog signal into a digital signal; at least one binarization unit converting the digital signal into binary data; a viterbi decoder performing viterbi decoding to detect binary data from the digital signal; and a level detector receiving the digital signal, receiving at least two binary data from one of the viterbi decoder and the at least one binarization unit, and detecting and outputting a level value for the viterbi decoding from the digital signal when a number of the at least two binary data, which correspond to each other on a time axis and have the same values, is equal to or greater than a predetermined number. Accordingly, it is possible to more precisely detect binary data from an analog signal.

Abstract: A defect signal detecting apparatus for an optical recording/reproducing apparatus that includes a maximum value detecting unit for detecting a highest amplitude among signals input during a maximum value detection period as a maximum value, a minimum value detecting unit for detecting a lowest amplitude among signals input during a minimum value detection period as a minimum value, an asymmetry detecting unit for calculating an amount &dgr; of asymmetry by detecting a maximum value ILmax and a minimum value ILmin of a signal IL having a maximum periodicity among the signal input, and a maximum value ISmax and a minimum value ISmin of a signal IS having a minimum periodicity among the signal input, and a defect determining unit for determining whether there is a defect in the signal input, using the maximum value, the minimum value and the amount &dgr; of asymmetry.