Method and system for improving retention performance of clock server

Abstract

The invention provides a method and a system for improving retention performance of a clock server. Aiming at a clock server equipped with a rubidium clock, a power-on timer is started when the clockserver is powered on, and different methods are executed according to the timing time of the power-on timer when the clock server is locked: A, when the timing of the power-on timer is smaller than afirst preset time period, a control word processing method is directly used for keeping data of the clock server; b, when the timing of the power-on timer is greater than a first preset time period and less than a second preset time period, a control word processing method and a window skipping average method are sequentially used to keep clock server data; and C, when the power-on timer is greater than a second preset time period, the clock server data is maintained by using a control word processing method and a linear Kalman infinite recursion method in sequence. According to the invention,sectional type retention data processing is adopted, so that the retention performance of each time period can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of keeping performance of a clock server, and in particular relates to a method and a system for improving keeping performance of a clock server. Background technique [0002] The block diagram of a traditional digital phase-locked loop is as follows: figure 1 As shown, the control word (control word) output by the filter generally uses a Filter (filter) to filter the control word. When the ref (reference) is gone, it is output with cw_filter (control word-filter) As the frequency output control of NCO (Numerical Controlled Oscillator), so as to achieve the purpose of frequency maintenance. In the prior art, the general method of cw_filter is to directly use the average filtering method, and the average window can be set, and some methods are to directly use the last control word value before ref is lost. [0003] The first-level clock server mainly uses the rubidium clock as the working clock of the syste...

AI Technical Summary

Problems solved by technology

[0006] Window jump average: If the same window is too short, the average effect will be poor. If the window is too long, the data used for keeping is the calculated value of the previous window, and there will be a certain deviation

[0007] Moreover, the simple average filtering effect is also general, and cannot fully reflect the real change of the control word.

[0008] from figure 2 According to the results of the actual environment shown, if the average filtering scheme is used at the beginning, the actual control word will be much worse than the averaged value, and the actual performance is not even as good as directly using the last control word before ref is lost.

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