Clock signal extraction device and method for extracting clock signal from data signal

Abstract

The invention provides a clock signal extraction device for extracting a clock signal from a periodic data signal, comprising a phase detector for detecting a first phase difference between rising edges of said data signal and a rising edges clock signal and for detecting a second phase difference between falling edges of said data signal and a falling edges clock signal; and a clock generator forgenerating said rising edges clock signal so that said first phase difference is minimized, for generating said falling edges clock signal so that said second phase difference is minimized, and for generating said clock signal in dependence on said first phase difference and said second phase difference. The invention further provides a method for extracting a clock signal from a periodic data signal.

Description

technical field [0001] The present invention relates to extracting clock signal data from a data signal in a digital communication system, such as an optical data signal in an optical communication system. In particular, the present invention relates to a clock signal extraction device and method for extracting a clock signal from a data signal. Background technique [0002] Serial communication systems require sampling clocks to be extracted from the serial stream, where the clock harmonics are not inherent in the signal itself. This extraction is performed by a non-linear circuit called a clock and data recovery (CDR) unit. The CDR is responsible for tracking low frequency phase changes in the signal by observing the signal's transitions and performing averaging. [0003] figure 2 A typical clock and data recovery (CDR) circuit 200 is shown that recovers a clock signal and data from a data signal using a phase locked loop (PLL). The CDR circuit 200 includes a phase det...

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Problems solved by technology

However, this solution suffers from a reduction in the signal-to-noise ratio of the transition amplitude, leading to false detection of the transition and false tracking of the signal

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