Circuit and method for restoring digital clock signal

Abstract

A circuit for recovering a digital clock signal and a method therefor is disclosed. The digital clock recovery circuit includes an analog-to-digital (A / D) converter and asymmetry corrector for converting a received analog signal into digital data and providing corrected digital data corrected by a binarization level which traces the center value of the received signal, a frequency error detector for detecting a frequency error from the corrected digital data, a phase error detector for detecting a phase error from the corrected digital data, and a digital low pass filter (LPF) for providing the frequency error and the phase error as a control voltage. It is possible to trace the asymmetry of the received signal more sensitively than in the conventional technology by realizing an asymmetry corrector for correcting the asymmetry of the digital data which has undergone the analog-to-digital (A / D) conversion, the phase error detector, and the LPF by a digital circuit, thus generating a system clock signal and to improve the reliability of the system by stably generating the system clock signal.

Description

technical field [0001] The present invention relates to the field of clock signal recovery, and in particular to a circuit and method for recovering a digital clock signal in a recording and / or playback device for an optical disc. Background technique [0002] In an apparatus for recording data on or reproducing data from an optical disc such as a compact disc (CD) or a digital versatile disc (DVD), a process for synchronizing a playback signal with a system clock signal is necessary. A phase-locked loop (PLL) circuit is one circuit used to perform this processing. [0003] The PLL circuit locks a phase by generating a system clock signal relative to a received signal through a voltage controlled oscillator (VCO) oscillating at a certain frequency, changing the frequency of the system clock signal, and locking the received signal to the changing system clock signal. Generally, after calculating the difference between the oscillation frequency of the VCO and the frequency of...

AI Technical Summary

Problems solved by technology

These functions are difficult to realize by analog structure

[0009] Also, when the LPF 140 for supplying the frequency error and the phase error as the control voltage of the VCO 150 is realized by an analog circuit, it is impossible to change the frequency band freely and noise is mixed in the signal

Therefore, it is difficult to apply the LPF realized by the analog structure to a newly developed optical disc product corresponding to a high multiple speed mode.

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