Frequency stability measurement method and system based on high-precision phase-frequency analysis

Abstract

The invention discloses a frequency stability measurement method and system based on high-precision phase-frequency analysis. The measurement method adopts an all-digital implementation scheme, uses amulti-channel high-speed ADC to directly perform sampling and digitization processing on analog frequency signals of a frequency source to be measured and a reference signal source, and then uses thedigital quadrature down-conversion technology to achieve dual-mixing measurement, and then obtains high-precision frequency difference measurement sequences through high-precision phase-frequency analysis, phase difference calculation and frequency difference calculation, and calculates the overlapping Alan variance to achieve frequency stability measurement of the frequency source to be measured. The measurement method avoids the disadvantages of difficult design and long development period of analog and semi-digital implementation schemes; the high-precision phase-frequency analysis algorithm lowers the demand for the quantify resolution of the measurement system ADC device compared with the current digital phase detector measurement method; and the hardware cost is reduced, and the ability to use higher rate ADC devices to increase the system's measurable frequency range is provided.

Description

technical field [0001] The invention relates to a frequency stability measurement method and system based on high-precision phase-frequency analysis, belonging to the technical field of electronic measurement. Background technique [0002] High-stable frequency signal sources, such as high-stable crystal oscillators and atomic clocks, are widely used in many fields such as aerospace, navigation and positioning, national defense and military, and communications. Frequency stability is an important indicator for evaluating the performance of frequency signal sources, reflecting the ability of the output frequency value of the frequency source to maintain a certain value within a period of time, and is usually described quantitatively using Allan variance. At present, the second-level stability of the crystal oscillator can reach 10 -12 , the second level stability of the atomic clock can reach 10 -15 , therefore, it is very important to study a high-precision frequency stabi...

AI Technical Summary

Problems solved by technology

However, the measurement results of the most commonly used digital phase detector phase measurement method are seriously affected by the quantization error of the ADC. It is required that the quantization resolution of the ADC chip used in the measurement system hardware is not lower than 12 bits, which makes it difficult for the system to use high sampling frequency. The ADC chip limits the measurable frequency range of the system, and cannot measure the very high frequency band signal output by the frequency signal source (such as the 100MHz signal output by the atomic clock)

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