Abstract: Specifically shaped filter responses enable power or amplitude measurements at the filter outputs to be simply transformed into accurate measurements of some desired function of the frequency (such as the frequency itself or log (frequency)) of any discrete tones within the filters' bandwidths. The invention can be used in conjunction with Fast Fourier Transform based filter banks. In cases where discrete tones are harmonically related, as in speech, the invention enables a simple determination of a weighted average of the harmonics' fundamental frequency, without having to first estimate the individual harmonics' frequencies.

Abstract: A method and apparatus for extracting information from human speech are dislosed. A speech signal is received into a bank of bandpass filters and the instantaneous amplitude modulation and frequency modulation of each harmonic in the speech waveform is determined. A logarithm of the instantaneous frequency of the speech fundamental frequency is determined, for example, by computing a weighted average of the frequency modulations of the harmonics. An output signal is formed having the logarithm of the frequency of the thus determined speech fundamental and the logarithms of the amplitude modulation for the ten lowest frequency speech harmonics and/or the speech envelope.