Abstract: A pitch synchronous sinusoidal synthesizer for multi-band excitation vocoders will produce excitation signals necessary to artificially mimic speech from input data. The input data will contain the pitch frequencies for current and previous synthesizing frame samples, starting phase information for all harmonics within the current synthesizing frame sample, magnitudes for each of the harmonics present within the current synthesizing frame sample, the voiced/unvoiced decisions for each of the harmonics within the current frame sample, and an energy description for the harmonics of the current synthesizing frame sample. The pitch synchronous sinusoidal synthesizer will produce the synthetic speech with a minimum of the distortion caused by the sampling and regeneration of the speech excitation signals. The pitch synchronized sinusoidal synthesizer has a plurality of pitch interpolators.

Abstract: A method and means to estimate the pitch of a speech or acoustic signal within a vocoder begins with the center clipping and low-pass filtering of the speech or acoustic signal to eliminate the formants from the speech or acoustic signal. An error function for each pitch is calculated for each pitch within the speech or acoustic signal. A fast tracking method is used to select the estimated pitch for the pitch or acoustic signal. A final check for the doubling of the pitch will minimize any incorrect estimation of the pitch.