A pitch extraction method using higher‐order joint moment

Abstract

A modified higher‐order joint moment method for a correct pitch extraction is proposed. The mean products of three vectorized samples are used, while the usual autocorrelation method uses the mean products of two samples. Each of three samples separated by the same sample interval is modified to a vector whose modulus is equal to the absolute value of the sample, and the argument is ± 120 deg in accordance with the sample's sign. Only when three original samples have the same sign does the product of three vectors become a real positive value. By averaging the products in a certain window, a sharp peak on the sample‐interval axis is obtained at the pitch period. The effectiveness of the method is examined with real voiced signals. The peak at the pitch period is much sharper than the peak of the autocorrelation method, and the spurious peaks are very small. These properties result in a correct pitch extraction. It is also shown that the influence of the pitch fluctuation has properties similar to those as in the autocorrelation method.