Time-Varying Signal Analysis Method Based On Linear Interpolation

To solve the problem of harmonic analysis of time-varying signals, an analysis method based on linear interpolator is proposed. Firstly, the noise in measuring equipment is filtered by input filter, and then the sample number of signals in a period is guaranteed to be an integer power of 2 by linear interpolator, and then the cascade subtraction of filters is carried out. The number of sampled values and the cosine roll down window are used to prevent the energy from spreading to the side lobe. Since the fundamental frequency of the system changes, frequency control is used to estimate the frequency and feedback to the linear differentiator module to adjust the time interval of the difference to ensure that the output signal sampling value is strictly an integer power of 2. Finally, the FFT transformation of the voltage and current data is carried out to analyze the current, voltage and impedance. The comparison results show that this method can be applied to harmonic analysis, especially in high-frequency harmonic analysis has a better performance and certain practicability.