Voice encoder and synthesizer

Claim 1

In a signal processing digital voice encoding device including sampling means for sampling analog voice signals and producing discrete samples from a frame of said voice signals, the improvement comprising: A first signal processing microprocessor in circuit with said sampling means and including foreground and background analyzing means for analyzing said samples by which said voice is modeled as a time-varying, linear, all-pole filter and a set of linear predictive reflection coefficients, which define the poles of said linear filter, are established by recursively filtering said samples from said sampling means, the foreground analyzing means multiplying, once each sample, speech datum in each sample by an appropriate Hamming weight which is recursively computed to obtain a set of correlation coefficients, and the background analyzing means computing from said correlation coefficients a set of linear predictice reflection coefficients and an energy estimate of said voice signal once each analysis frame; a second signal processing microprocessor in circuit with said sampling means and including pitch detector means for making a voicing decision and, when the sample includes voiced speech, determining the pitch of the voice from the samples of the sampling means, said pitch detector means comprising a low pass filter, a peak detector, a pitch and voicing estimator and means for smoothing output signals; and Controller microprocessor means in circuit with said first and second signal processing microprocessors for arranging the outputs of the analyzing means and the pitch detector means in a format suitable for digital transmission and for initializing said first and second processing elements with constants determining a sampling rate, an analysis frame size, and a linear predictive model order, wherein said first and second signal processing microprocessors and said controller microprocessor means form a parallel, distributed, signal processing circuit.