Normalization of the Voice Spectrum
Caldwell P. Smith · The Journal of the Acoustical Society of America · 1957
Measurement of the spectrum pattern of voice signals by a method that normalizes (i.e., makes the measurement unresponsive) with respect to amplitude fluctuations offers some powerful advantages. The relative amplitude at all frequency positions in the voice spectrum pattern is significantly correlated with the particular speech event; therefore a measurement of the total spectrum pattern offers a means of maximum utilization of the speech signal information. Normalization has the effect of slowing down the rate of change of the signal parameters that specify the voice spectrum, abstracting the common-mode fluctuation due to voice amplitude and specifying it as a separate parameter. Further, a specification of the normalized spectrum patterns of speech offers in principle a more economical specification than one in which formant frequencies are specified as independent parameters. The normalizing method has been reported previously [C. P. Smith, J. Acoust. Soc. Am. 28, 159 (1956)]; some speech data taken with normalization are presented.