Method for accurately acquiring signal frequency and frequency stability through digital phase comparison

Abstract

The invention belongs to the technical field of phase comparison. The method is especially suitable for phase comparison of different nominal frequencies. The invention specifically relates to a method for accurately acquiring signal frequency and frequency stability through digital phase comparison. The phase processing technology is combined with the development of the modern digital technologyon the basis of improving the frequency measurement precision. An analog-to-digital converter (ADC) is adopted as a phase discriminator to realize combination of inter-phase quantization processing and amplitude, phase comparison of any signal is expanded to a phase difference group, and direct phase comparison and measurement of any periodic signal with different nominal values are realized by taking a minimum common multiple period as a period. The digital measurement technology is adopted, direct comparison between different nominal frequency signals can be achieved through the digital technology and the relation between phases of periodic signals, and compared with a traditional analog measurement technology, the method has better anti-interference capacity, and frequency normalizationprocessing is not needed.

Description

technical field [0001] The invention belongs to the technical field of phase comparison, and is especially suitable for phase comparison of different nominal frequencies, in particular to a method for digital phase comparison to accurately obtain signal frequencies. Background technique [0002] Time-frequency measurement is the physical quantity with the highest measurement accuracy at present, and it is widely used in aerospace, satellite navigation, communication, geological exploration and other fields. In addition, due to the application of a large number of voltage-frequency conversions, the measurement of a wide range of physical quantities is converted into the measurement of frequency quantities, which puts forward higher requirements for the accuracy of frequency measurement. Of course, the frequency source is the standard of frequency measurement, and the realization of high-precision measurement method is inseparable from the support of high-precision frequency s...

AI Technical Summary

Problems solved by technology

However, these methods require that the period values ​​of the measured and reference signals are the same or have a certain proportional relationship.

In the traditional frequency standard comparison, the difference frequency cycle method can directly compare the phase of the signal, but because the size of the difference frequency cycle is difficult to determine and standardize, it is impossible to avoid the interference of dead zones and nonlinear errors on the measurement results; double The mixing time difference method combines the differential method and the intermediate source method, and mixes the two comparison signals with the third auxiliary (intermediate) oscillator respectively. Through the symmetry of the two channels, the dead zone and nonlinearity are successfully avoided. The interference to the result improves the resolution of the measurement, but the complexity of the entire system increases due to the intervention of intermediary sources

There are still many disadvantages in the traditional frequency standard comparison, such as high power consumption, low comparison accuracy, complex wiring, etc.

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