Fundamental frequency estimator, active noise control device, fundamental frequency estimation method and fundamental frequency estimation program

摘要

PROBLEM TO BE SOLVED: To accurately estimate a fundamental frequency with a small amount of calculation and a small amount of delay while avoiding a delay associated with a fast Fourier transform. SOLUTION: Input signals are sequentially acquired, and each time a sample point of an input signal is acquired, an amplitude spectrum of the input signal is calculated using a gradual equation including a previous value of the sample point, and the amplitude spectrum is calculated. Extract the peak frequency. Also, each time a sample point is acquired, the band including the peak frequency of the amplitude spectrum is emphasized. Then, the autocorrelation function is calculated using a recurrence formula including the previous value of the autocorrelation function, and the peak frequency of the autocorrelation function is set as the fundamental frequency. [Selection diagram] Fig. 1