CN105721092A - Method for improving time synchronization precision of distributed system by means of resampling technology - Google Patents

Abstract

The invention provides a method for improving time synchronization precision of a distributed system by means of a resampling technology. The method comprises the steps: generating a reference clock from a primary station or external equipment; sampling by means of a sampling frequency which is higher than the frequency multiplication of the reference clock by each operator station; and then aligning with the recent rising (declining) edge of the reference clock, and performing frequency-down resampling to acquire the acquisition data. As the synchronization precision of the distributed system mainly depends on the sampling clock frequency of the operator stations, the higher the sampling clock frequency is, the smaller the synchronization error is, and the higher the synchronization precision is. Besides, as all the operator stations share one primary station reference clock, the influence of inconformity of the clock stability for different operator stations on the synchronization precision can be eliminated, wherein the inconformity of the clock stability is caused by time drifting, temperature, aging of elements and the like.

Description

Resampling technique improves the method for distributed system timing tracking accuracy

Technical field

The invention belongs to industrial measurement and control field, relate to a kind of method and system realizing distributed system data collection synchronous.

Background technology

In the measurement system of centralized management, all Measurement channel adopt same local clock, and synchronousness is better.But in a distributed system, usual operator station quantity is more and master station is distant, therefore, it is that operator station is equipped with local reference clock during many Distributed system designs, Measurement channel relies on the sampling clock of reference clock frequency dividing generation and completes to gather timing, thus realizing the synchronous acquisition of Measurement channel between all operations person station, see Fig. 1.

The problem brought is, the crystal oscillation frequency at different operating person station exists time and phase deviation, and is affected by the factor such as variations in temperature and electromagnetic interference, even if all reaching time synchronized at all nodes sometime, their time also can engender deviation.Therefore, requiring in higher distributed system at synchronicity, improving different operating person's timing tracking accuracy between Measurement channel of standing is the key issue needing solution badly.

Technical scheme

In order to solve the technical problem of existing distributed system synchronousness difference, the present invention provides a kind of method utilizing resampling technique to improve distributed system timing tracking accuracy.

The technical solution of the present invention is as follows:

A kind of method improving distributed system timing tracking accuracy, it is characterized in that and comprises the following steps:

1) reference clock and initial sample clock are produced

1.1) master station or other external equipment produce a reference clock, and reference clock frequency equals to or more than destination sample frequency；

1.2) each operator station produces respective initial sample clock according to respective reference clock, and initial sample clock frequency is more than reference clock frequency；

2) initial sample data sequence is obtained

All Measurement channel in each operator station carry out data acquisition by the initial sample clock of our station, it is thus achieved that initial sample data sequence；

3) resampling obtains destination sample data sequence

In each operator station, initial sample data sequence is carried out down sample process according to destination sample frequency by all Measurement channel,

That is: in each destination sample cycle, according to target sample frequency carries out extracting with the rising edge of reference clock or the immediate initial sample data of trailing edge as effective sampling points, it is thus achieved that destination sample data sequence.

Assuming that the destination sample frequency of distributed system data acquisition is fs, then step 1.1) in reference clock frequency be fr=l*fs, l is positive integer, then step 1.2) in the frequency of operator station initial sample clock be m*fr=m*l*fs, m be positive integer.

Compared with prior art, advantage is the present invention:

The present invention adopts resampling technique, it may be achieved distributed system synchronous acquisition, Synchronization Control etc. are applied.Its synchronization accuracy depends primarily on the sample clock frequency of operator's website, and sample clock frequency is more high, and synchronous error is more little, and synchronization accuracy is more high.A shared master station reference clock further, since all operations person stands, also can eliminate the inconsistent impact on synchronization accuracy of different operating person's station clock degree of stability caused by time drift, temperature, component ageing etc..

Accompanying drawing explanation

Fig. 1 is common distributed system synchronization principles；

Fig. 2 is that resampling technique improves distributed system synchronization accuracy schematic diagram.

Detailed description of the invention

Below in conjunction with accompanying drawing, the optimal way of the present invention is illustrated.

Distributed system is made up of multiple operator stations, and each operator station is made up of multiple Measurement channel, and the multiple Measurement channel within each operator station all rely on the sampling clock of this operator station and carry out data acquisition.What finally to obtain is the sample data sequence being fs with sampling rate of all Measurement channel, and the timing tracking accuracy of these acquisition sequence is significantly high.

Resampling technique of the present invention improves the ultimate principle of distributed system synchronization accuracy: produced a road reference clock by master station or external equipment, each operator station is acquired with the higher sample frequency of reference clock frequency multiplication, then nearest with reference clock rising (or decline) is along aliging, carry out frequency reducing resampling, obtain and gather data, see Fig. 2.

During use, the reference clock of master station can be equal to or be the positive integer times of destination sample rate, i.e. fr=l*fs, l=1,2 ..., carrying out reference clock setting according to such rule, advantage is when obtaining double sampling sequence, provides unified time standard for all operations person's sampling clock of standing.

The frequency multiplication m*fr=m*l*fs, m=1,2 that initial sample clock frequency is reference clock of operator station, 3 ..., the sampling rate of the data sequence after frequency reducing resampling is destination sample rate fs.The setting of initial sample clock frequency of standing according to such rule person of being operated, advantage is that all operations person stands and all can obtain the initial sample data sequence higher than destination sample frequency, one group of higher double sampling data sequence of synchronization accuracy, i.e. destination sample data sequence can be extracted according still further to destination sample frequency.

Comparison diagram 1 and Fig. 2, adopt resampling technique to make the synchronous error of distributed system be reduced to 1/ (m*l*fs) by 1/fs, and synchronization accuracy improves m*l times.

Claims (2)

1. the method improving distributed system timing tracking accuracy, it is characterised in that: comprise the following steps:

1) reference clock and initial sample clock are produced

1.1) master station or other external equipment produce a reference clock, and reference clock frequency equals to or more than destination sample frequency；

1.2) each operator station produces respective initial sample clock according to respective reference clock, and initial sample clock frequency is more than reference clock frequency；

2) initial sample data sequence is obtained

All Measurement channel in each operator station carry out data acquisition by the initial sample clock of our station, it is thus achieved that initial sample data sequence；

3) resampling obtains destination sample data sequence

In each operator station, initial sample data sequence is carried out down sample process according to destination sample frequency by all Measurement channel,

That is: in each destination sample cycle, according to target sample frequency carries out extracting with the rising edge of reference clock or the immediate initial sample data of trailing edge as effective sampling points, it is thus achieved that destination sample data sequence.

2. the method for raising distributed system timing tracking accuracy according to claim 1, it is characterised in that:

Assuming that the destination sample frequency of distributed system data acquisition is fs, then step 1.1) in reference clock frequency be fr=l*fs, l is positive integer, then step 1.2) in the frequency of operator station initial sample clock be m*fr=m*l*fs, m be positive integer.