### ASA 127th Meeting M.I.T. 1994 June 6-10

## 1pSP13. Precise determination of fundamental frequency by utilizing
harmonic structure of speech.

**Jouji Suzuki
**

**
Miyuki Seto
**

**
Tetsuya Shimamura
**

**
**
*Dept. of Inf. and Comput. Sci., Saitama Univ., 255 Simo-okubo, Urawa, 388
Japan
*

*
*
Precise and correct measurement of fundamental frequency F0 is requested
in the detailed analysis of speech sound and analysis synthesis telephony
employing F0. This paper proposes a new method to estimate F0 employing the
harmonic number and its frequency. At first, 256 pts. of speech samples are
windowed and ``0''s are added to 1024 pts. The magnitude spectrum is calculated
by FFT and smoothing is carried out by moving average of 5 pts. Such procedures
make it easy to identify the spectrum peaks and improve the accuracy of their
frequency. Every harmonic is identified from the peak of the spectrum and an
harmonic number is assigned. Now fundamental frequency is calculated by (nth)
harmonic frequency)/n. Finally the fundamental frequency is computed as the
weighted mean, which is proportional to n, on harmonics located under 2 kHz.
This idea is quite similar to getting F0 as the coefficient of a regression
line passing through the origin. The accuracy of F0 obtained by this method is
expected to be less than 3 Hz in female voice when the sampling frequency is 10
kHz. Experimental results indicate that the proposed method gives more precise
and reasonable pitch information than the cepstrum or correlation method does.