US 6,192,016 B1 · Data recovery apparatus and method for optical disk reproduction systems

Abstract

In a data recovery apparatus and method for an optical disk reproduction system, a technique for digital recovery of data from an analog radio frequency (RF) signal is provided. An analog-to-digital converter (ADC) converts an analog radio frequency (RF) signal into a digital signal in response to a reference clock signal. A first adder combines an asymmetry error level to the digital RF signal. An adaptive digital equalizer digitally controls the level of the result added by the first adder, in response to a control signal. A digital level detector calculates the asymmetry error amount using the result added by the first adder, and outputs the control signal according to the output of the adaptive digital equalizer and predetermined coefficients. A viterbi decoder decodes the output of the adaptive digital equalizer into a bit train. A digital edge detector calculates the accuracy of sampling by the analog-to-digital converter, using the result added by the first adder, and outputs phase and frequency control signals according to the calculated accuracy. A reference signal generator outputs the reference clock signal having a frequency which varies in response to the phase and frequency control signals. Thus, data can be accurately recovered.

Claims18

Dependent claims

A data recovery apparatus in an optical disk reproduction system including a photodiode and a demodulator comprising:

an analog-to-digital converter for converting an analog radio frequency (RF) signal input from the photodiode into a digital RF signal in response to a reference clock signal;
a first adder for combining the digital RF signal with an asymmetry error signal;
an adaptive digital equalizer for controlling the level of the digital RF signal in response to an equalizer control signal, and for generating an equalized digital RF signal;
a digital level detector for calculating the degree of asymmetry error in the digital RF signal, and for generating the asymmetry error signal in response to the asymmetry error, the digital level detector further generating the equalizer control signal in response to the equalized digital RF signal;
a decoder for decoding the equalized digital RF signal to generate a bit train for transmission to the demodulator;
a digital edge detector for determining the accuracy of sampling by the analog-to-digital converter using the digital RF signal, and for generating phase and frequency control signals according to the determined accuracy;
and
a reference signal generator for generating the reference clock signal having a frequency which varies in response to the phase and frequency control signals.

5 more elements

A data recovery method performed in an optical disk reproduction system including a photodiode for outputting an analog RF signal and an eight to fourteen demodulator (EFDM) for converting the pattern of a bit train, the method comprising the steps of:

(a) obtaining a digital RF signal by converting the analog RF signal to a digital RF signal by sampling according to a reference clock signal;
(b) compensating for asymmetry error in the digital RF signal, controlling frequency and phase of the reference clock signal according to an accuracy degree of sampling, and digitally equalizing the digital RF signal;
and
(c) obtaining the bit train by Viterbi-decoding the equalized digital RF signal.

1 more element

Dependencies are inferred from the claim text.

Data recovery apparatus and method for optical disk reproduction systems

Life of this patent

Data recovery apparatus and method for optical disk reproduction systems

Life of this patent

Abstract

Claims18