Phase detection method for clock recovery and apparatuses

Abstract

The embodiment of the invention provides a phase detection method for clock recovery and apparatuses. The apparatuses include a phase detector including a calculating unit. The calculating unit calculates a phase difference according to the product of receiving powers at different times so as to carry out clock recovery by using the phase difference; and the receiving powers are obtained by carrying out sampling on input signals by a predetermined sampling rate, wherein the predetermined sampling rate is twice larger than the symbol rate. According to the method and the apparatuses, because the phase difference is calculated according to the product of the receiving powers at different times, a problem that the traditional phase detection method is invalid under the circumstances that the large frequency difference or line width exists or the sending signal is the Nyquist signal with the spectral width close to the symbol rate can be solved.

Description

technical field [0001] The present invention relates to the technical field of optical communication, in particular to a phase detection method for clock recovery, a phase detector, a clock recovery device including the phase detector, and a coherent optical receiver including the clock recovery device. Background technique [0002] In a communication system, the signal at the sending end reaches the receiving end through channel transmission. During this process, the signal waveform is often severely distorted. At the receiving end, if no processing is done, the sent data cannot be obtained. In an actual receiver, clock and data recovery (CDR) is usually performed. Among them, the purpose of clock recovery (clock recovery, CR) is to generate a clock signal locally, and the frequency and phase of the clock signal are consistent with the frequency and phase of the symbol change of the received signal. [0003] figure 1 and figure 2 is a schematic diagram of a coherent op...

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Problems solved by technology

[0009] Embodiments of the present invention provide a phase detection method and device for clock recovery, to solve the problem in the case of a large frequency difference or line width, or when the transmitted signal has a spectral width close to the symbol rate (the spectral roll-off coefficient is small ) in the case of the Nyquist signal, the problem that the traditional phase detection method fails

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