Method for regulating clock frequency customer terminal and system

Abstract

A method for regulating frequency of clock includes filtering virtual clock (VC) pulse to obtain network time delay wave form, filtering jitter of wave form when network is on transmission, judging whether phase difference accumulation value of VC to local recovery clock is over preset threshold or not at preset time interval (PTI) and judging whether there is network time delay jitter over preset message arrival frequency and amplitude range or not at PTI if it is, regulating frequency of two said clocks to be identical if it is or otherwise decreasing said value of two said clocks. The client end for realizing said method is also disclosed.

Description

technical field [0001] The present invention relates to the field of communication services, in particular to a method, client and system for adjusting clock frequency. Background technique [0002] PWE3 (Pseudo-Wire Emulation Edge-to-Edge Virtual End-to-End Pseudowire) is a technical mechanism capable of simulating important characteristics of telecommunication services on PSN (Packet Switch Network). The simulation services include Ethernet services, frame relay services, ATM (Asynchronous Transfer Mode) services, TDM (Time Division Multiplex) services, etc., especially the PWE3 implementation of TDM is more complicated, because the server will send messages to the client, However, the message will reach the client through the PSN. During the PSN network transmission process, data packet loss, delay, delay jitter and other phenomena may occur, which will cause the virtual clock frequency recovered by the client through the message to be different from the local recovered c...

AI Technical Summary

Problems solved by technology

It took an hour for the amplitude of the network delay to rise from value A to value B, and the delay increment is B-A=2us, which is equivalent to a network delay jitter with a frequency of 10-3Hz and an amplitude of 2us; but such a network Delay jitter is not considered when presetting a certain clock frequency and amplitude range

Therefore, the client cannot recognize that such jitter is caused by the network itself, and adjusts the frequency adjustment of the local recovery clock when it exceeds the preset low-frequency drift of 1Hz to 10E-2Hz and 0.2us, resulting in the situation shown in Figure 1. The virtual clock frequency fluctuates

[0009] To sum up, the method in the prior art is to consider the changes of the PSN network in advance, and preset the frequency and amplitude range of message arrival on the client side. When the preset changes occur in the PSN, the client can filter other changes impact on packet arrival frequency; however, when the preset packet arrival frequency and amplitude range are exceeded, changes in the PSN will be added to the frequency at which the client receives packets, which will affect the rate at which the client receives packets. Frequency, that is, it will cause a difference between the virtual clock and the local recovered clock, resulting in misadjustment of the local recovered clock frequency

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