A Digital Method for Measuring Alternating Current Frequency

Abstract

The invention discloses a method for digital measuring of alternating current frequency. A digital integration and interpolation mode is used for processing continuous digital sampling signals, the virtual occurrence time of an integral start point P1 and the virtual occurrence time of an integral end point k which is acquired according to an interpolation mode after the signals cross a positive peak and a negative peak are used for calculating the zero point of electrical signals, the frequency or the period of the electrical signals are calculated through the zero crossing point of the electrical signals, then the zero point of the electric signals can be calculated through the sampling occurrence time of P1 and the virtual occurrence time of k, and the frequency or the period of the electrical signals can be calculated through the zero crossing point of a series of electrical signals. According to the method, low frequency signals do not need to be converted into square waves, the method is particularly suitable for frequency measuring of low-frequency sinusoidal signals, system detecting is convenient, hardware cost is low, the anti-jamming capability of a system is high, the method is simply and reasonably achieved, and data are accurate and reliable.

Description

technical field [0001] The invention relates to a method for digitally measuring the frequency of alternating current, which can also be used for frequency measurement of low-frequency sinusoidal signals, triangular wave signals, sawtooth wave signals and the like with fixed frequency or little frequency change. Background technique [0002] In daily life and production process, it is often necessary to monitor the frequency of the signal. In the existing frequency measurement methods for low-frequency signals, the low-frequency signal is first formed into a square wave through a shaping circuit, and the time interval T between two adjacent rising or falling edges of the square wave is detected, and the frequency is obtained by calculating the reciprocal, but this The anti-interference ability of this method is poor. In addition, there are some methods for measuring frequency by software, such as: zero-crossing method, analytical method, error minimization principle algorit...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to propose a method for digitally measuring the frequency of alternating current, which can also be used to solve the shortcomings of the existing technology that the frequency measurement accuracy of low-frequency electrical signals is not accurate enough or the amount of calculation is too large during the measurement process. Frequency measurement of low-frequency sinusoidal signals, triangular wave signals, sawtooth wave signals, etc. at a fixed frequency or with little frequency change

Images