Method and device for synchronizing frequencies of PTP master clock and slave clock

Abstract

The invention provides a method and device for synchronizing the frequencies of a PTP master clock and a slave clock, and relates to the technical field of frequency synchronizing. The method includes the steps of determining the measurement value of clock deviation between the PTP master clock and the PTP slave clock each time, conducting calculation through a Kalman filtering method according to the measurement value of the clock deviation, determining the estimation value of the clock deviation between the PTP master clock and the PTP slave clock each time, determining the frequency deviation of the PTP slave clock relative to the PTP master clock at the kth time according to the estimation value of the clock deviation at the kth time and the estimation value of the clock deviation at the (k-1)th time, converting the frequency deviation of the PTP slave clock relative to the PTP master clock at the kth time into a voltage signal through a digital-to-analog converter, outputting the voltage signal to the voltage control end of a voltage control crystal oscillator of the PTP slave clock so as to make the voltage control crystal oscillator of the PTP slave clock output a frequency signal to serve as the datum frequency of the PTP slave clock, and synchronizing the datum frequency and the frequency of the PTP master clock. By means of the method and device, the problem that in the prior art, the synchronization of the frequencies of the PTP master clock and the PTP slave clock is not accurate enough is solved.

Description

technical field [0001] The invention relates to the technical field of frequency synchronization, in particular to a method and device for frequency synchronization between a PTP master clock and a slave clock. Background technique [0002] PTP Precision Time Protocol (Precision Time Protocol, referred to as PTP) is a technical protocol for time synchronization through Ethernet, which is used as an alternative to Global Positioning System (GPS) to solve the time synchronization problem of 3G / 4G base stations , has been applied in the metropolitan area network of telecom operators (such as China Mobile). Since PTP adopts the method of adding time stamps at the physical layer (Physicallayer, PHY), compared with the Network Time Protocol (NetworkTimeProtocol, NTP) which adds time stamps at the application layer, it avoids the problems caused by the operating system and the protocol stack. Jitter, thus greatly improving the synchronization accuracy. Currently, the traditional ...

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Problems solved by technology

[0004] Embodiments of the present invention provide a method and device for frequency synchronization between a PTP master clock and a slave clock, to solve the problem that the frequency synchronization method in the prior art cannot accurately calculate the local frequency deviation, and the frequency synchronization between the PTP master clock and the slave clock imprecise problem

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