Method for measuring sine signal with high accuracy

Abstract

The invention provides a method for measuring a sine signal with high accuracy, which is realized by steps of data acquisition system sampling, discrete Fourier transform, peak searching, frequency measurement, and amplitude and phase measurement. The invention provides an interpolating method capable of correcting leakage effect in a long-range and a short-range simultaneously to realize high accuracy measurement on parameters of the sine signal by the Fourier transform algorithm. The method can improve the accuracy for measuring the sine signal to over 10.

Description

technical field [0001] The invention belongs to the technical field of signal measurement and relates to a high-accuracy sinusoidal signal measurement method. Background technique [0002] The measurement of sinusoidal AC signals has important applications in electrical engineering, electrometrics, and other fields. For example, the measurement of electric energy, the fluctuation of the grid frequency, the evaluation of the dielectric loss angle reflecting the defects of high-voltage electrical equipment such as damp, deterioration or gas discharge in the insulation, the verification and calibration of the AC signal generator, etc., all require sinusoidal signals Accurate measurement of frequency, amplitude, initial phase, etc. [0003] A sinusoidal signal has three parameters: frequency, amplitude, and initial phase. There are various methods for measuring sinusoidal signals. In order to measure the frequency, the zero-crossing detection method based on the hardware circu...

AI Technical Summary

Problems solved by technology

At present, a variety of correction methods have been proposed, which are mainly used to correct the measurement error caused by the short-range leakage effect, and the accuracy after correction can reach 10 -5 ~10 -4 About, but this level of accuracy does not meet the requirements of some precision measurement occasions

For the long-range leakage effect, especially the measurement error caused by the negative frequency point leakage effect, no effective correction method has been seen so far

However, this part of the error can sometimes reach 10 -4 around, which greatly reduces the accuracy of DFT-based measuring instruments

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