A new method of cepstrum analysis using comb type quefrency window.
Ghen Ohyama, Sigeru Katagiri, Kido Ken'ichi · Journal of the Acoustical Society of Japan (E) · 1981
This paper describes the use of comb type quefrency window in the cepstrum analysis. A good result is obtained with a Hanning lifter in case of low pitch frequency. But in case of high pitch frequency, it is sometimes impossible to separate two formants. The comb lifter is presented to overcome this difficulty; that is, the lifter length is fixed so as to separate the closest formants, and the peaks in the cepstrum due to the periodicity of speech are suppressed using the comb lifter. It is necessary for the utilization of the comb lifter to estimate exact pitch period. Since it is hard to estimate an exact pitch period, the pseudo-comb lifter which does not need the exact pitch period is proposed. For the case of the high pitch frequency, the comb lifter is effective and for the case that the pitch period is undetectable, the proposed pseudo-comb lifter is effective.