Clock data recovery apparatus and frequency control circuit

Abstract

A clock data recovery apparatus includes an oscillator, a sampler circuit, and a frequency control circuit. The oscillator generates a clock signal according to a bias voltage. The sampler circuit samples an input data signal to generate a sampling signal according to the clock signal. The frequency control circuit generates the bias voltage by performing integration calculation, digital-to-analog conversion, and low-pass filtering for the sampling signal. Correspondingly, the invention also provides a frequency control circuit which include capabilities of reducing more noise as well as tracking larger frequency offset for a data signal.

Description

technical field [0001] The present invention relates to a clock data recovery scheme, and more particularly, to a clock data recovery device and a corresponding frequency control circuit. Background technique [0002] Generally speaking, ideally, a traditional clock data recovery device can be used to track the frequency offset (offset) of the data signal, so as to lock the frequency of the data signal. Conventional clock data recovery devices include a low pass filter. However, in practice, conventional clock data recovery devices are limited by the bandwidth of their low-pass filters, process variations during manufacture, and / or harsh environmental conditions (such as rapid temperature changes). For example, since a wider bandwidth can filter out less noise, if the low-pass filter is implemented with a wider bandwidth, the conventional clock data recovery device must not be able to reduce more noise. However, if the low-pass filter is implemented with a narrow bandwidt...

AI Technical Summary

Problems solved by technology

However, in practice, conventional clock data recovery devices are limited by the bandwidth of their low-pass filters, process variations during manufacturing, and / or harsh environmental conditions (such as rapid temperature changes)

For example, since a wider bandwidth can filter out less noise, if the low-pass filter is implemented with a wider bandwidth, the conventional clock data recovery device must not be able to reduce more noise

However, if the low-pass filter is implemented with a narrow bandwidth, the conventional clock data recovery device must not be able to track the large frequency offset of the data signal

This problem will become more serious if the traditional clock data recovery device is used in harsh environmental conditions

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