FUNDAMENTAL FREQUENCY ESTIMATION DEVICE, ACTIVE NOISE CONTROL DEVICE, FUNDAMENTAL FREQUENCY ESTIMATION METHOD, AND FUNDAMENTAL FREQUENCY ESTIMATION PROGRAM

摘要

The present invention avoids delays occurring along with a fast Fourier transform and accurately estimates a fundamental frequency with little computation and few delays.　Input signals are sequentially acquired, and, each time a sample point in an input signal is acquired, a recurrence formula which includes the previous value of the sample point is used to calculate the amplitude spectrum of the input signal, and the peak frequency of the amplitude spectrum is extracted. Furthermore, each time a sample point is acquired, a bandwidth that includes the peak frequency of an amplitude spectrum is emphasized. Then a recurrence formula that includes the previous value of an autocorrelation function is used to calculate the autocorrelation function, and the peak frequency of the autocorrelation function is set as a fundamental frequency.