Correction Method of Discrete Spectrum Low Frequency Components Based on Time Delay

Abstract

The invention relates to a method for correcting low-frequency components in a discrete spectrum based on time delay, which is characterized by comprising the following steps: (1) dividing a discrete time signal into three equilong sections according to a certain time delay, summating each section of the time signal respectively and getting three sums; (2) utilizing the symmetry of the spectrum of the discrete time signal and utilizing a Fourier transform formula to get an expression form about the spectrum correction of the low-frequency components in the discrete spectrum; (3) combining the three sums with the expression form about the spectrum correction of the low-frequency components in the discrete spectrum for getting the frequency and the phase of the low-frequency components in the discrete spectrum; and combining with the expression form about the spectrum correction (2) according to the obtained frequency and the phase and further getting the amplitude of the low-frequency components; and (4) correcting the phase and getting the corrected value of the phase. The method is small in amount of calculation, high in calculation accuracy, simple and easy to operate and applicable to any window functions, and can improve the efficiency and the accuracy of the correction of the low-frequency components in the discrete spectrum.

Description

technical field [0001] The present invention relates to a method for correcting low-frequency components of discrete spectrum, in particular to a method for correcting low-frequency components of discrete spectrum based on time delay. Background technique [0002] In the field of spectrum correction, the signal frequency is relative. When the frequency is less than twice the frequency resolution of the spectrum, it is regarded as a low-frequency signal, otherwise it is regarded as a high-frequency signal. For example, for a 30Hz single-frequency signal, if the frequency resolution is 20Hz, the signal should be regarded as a low-frequency signal in the field of spectrum correction; if the frequency resolution is 1Hz, the signal should be regarded as a high-frequency signal in the field of spectrum correction. [0003] In engineering practice, for low-frequency signals, there are not enough fluctuation cycles in the collected samples, and the spectrum will be interfered by neg...

AI Technical Summary

Problems solved by technology

According to the document "Acta Metrology" 2008.29(2): pp. 168-171, the authors Zhang Haitao and Tu Yaqing proposed a low-frequency correction method based on phase difference in the article "A New Method for Phase Difference Measurement Based on FFT Considering Negative Frequency Effects" , but the correction algorithm is more complex, it needs to solve the equations, and the calculation amount is large

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