스펙트럼차에 기초한 LSP 추출방법

An LSP Extraction Method Based on the Spectral Difference

In this paper, we propose a new method to extract the line spectrum pair (LSP) frequencies. When speech signal is analyzed by the autocorrelation method, the spectral difference in the logarithmic spectra of the model at steps p and p-1 oscillates. There are p-1 frequency points where the values of the spectral dfference take on either maximum or minimum between 0 and half sampling frequency. We show that these frequencies are excatly the LSP frequencies of order p-1, which can be found by searching the frequencies where the spectral difference reaches either maxima or minima. also, the LSP frequencies of order p can be obtained from this spectral difference. In this case, we derive the expression governing the pth order LSP frequencies. The efficient search for finding the LSP frequencies of order p can be done by proving the property that the LSP frequencies of order p and p-1 are interlaced with each other.