Formant-Frequency Extraction by the Method of Moment Calculations
Jouji Suzuki, Yasuo Kadokawa, Kazuo Nakata · The Journal of the Acoustical Society of America · 1963
The method of moment calculation was used for formant-frequency extraction in computer processing from a digitalized spectrum pattern. Special attention was paid to the separation of frequency range for each formant. F̄, the first-order moment of speech power spectrum, and F2e, the ratio of the second-order moment to the first one of the spectrum, are used in this separation. Formants are calculated as first-order moments within the separated portion of the spectrum. Analyses of errors of extracted formant frequencies due to the various factors such as the increase of pitch frequency, etc., were carried out by using the synthesized vowel-type spectra simulated on the computer. This analysis and comparisons of extracted formant frequencies from the natural speech with the corresponding spectrograms have proven that the method gives acceptable results in actual speech analysis. The results can be regarded as first approximation of formant frequencies as bases of more detailed analysis such as “analysis-by-synthesis.”