Method for synthesizing high accuracy digital time-frequency standard

Abstract

The invention discloses a high precision digital time frequency standard synthesis method, the method being: A. using full digital distinguishing phase and frequency synthesis, and separating the frequency generation and correction; the oscillator working in a free oscillation mode; B. using high-precision phase cumulative method to achieve frequency synthesis, and after combining with the DA converting, outputting to the filter to process noise reduction; C. using digital filtering method to process the distinguishing phase data, and getting the oscillator frequency deviation; D. using the output frequency signal dividing frequency and sending into distinguishing phase device, to achieve the monitor of the frequency synthesizer quality. This invention uses full digital distinguishing phase and frequency synthesis, separates the frequency generation and the correction, and solves control coupling problem; the oscillator works in a free oscillation mode, phase noise being lower, stability being good; meanwhile it supports multiple reference sources to parallel process, very suited to the high-precision time frequency standard synthesis cases, such as satellite timing and others.

Description

technical field [0001] The invention relates to a frequency synthesis and time scale synthesis technology in the field of electronic technology, in particular to a high-precision digital time-frequency scale synthesis method. Background technique [0002] At present, the high-precision time-frequency standard synthesis commonly used at home and abroad mainly adopts the analog phase-locked loop technology. [0003] The phase-locked loop mainly includes a voltage-controlled oscillator, a frequency divider, a phase detector and corresponding control algorithms. The working process is as follows: [0004] The output frequency signal of the voltage-controlled oscillator is sent to the phase detector after frequency division, and is phase-detected with the reference source signal, and the phase difference data obtained is sent to the control algorithm for processing, and the output frequency of the voltage-controlled oscillator and the reference are obtained through proper calcul...

AI Technical Summary

Problems solved by technology

[0007] The frequency stability of the voltage-controlled oscillator can be achieved by constant temperature and other methods, but the frequency accuracy generally needs to be measured and debugged one by one, and it is difficult to control in large-scale production

In high-precision time-frequency standard synthesis, the loop bandwidth is generally very narrow. If the output frequency of the voltage-controlled oscillator is too different from the reference source frequency, it will easily cause the control loop to overshoot and fail to converge.

[0008] (2) Long loop establishment time

In this way, on the one hand, the possibility of loop overshoot cannot be fundamentally avoided; on the other hand, the establishment time of the loop will be very long, which will affect the availability of the system

[0010] (3) The system stability is not good

[0011] Due to the inherent frequency aging characteristics of the oscillator, the oscillator frequency will shift a lot for a long time (more than 1 year). After exceeding the tolerance range of the system, the system will not work, and the interference introduced in the loop may also cause the system to fail. Stablize

Therefore, the system must be corrected after a certain period of time, increasing maintenance costs

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