Channel Vocoder with Digital Pitch Extractor
J. Tierney, Bernard Gold, Vincent J. Sferrino, J. A. Dumanian, Everett Aho · The Journal of the Acoustical Society of America · 1964
An experimental, digitized channel vocoder has been designed and built at the Lincoln Laboratory. This vocoder differs from previous vocoders in the design of the pitch extractor. Pitch is obtained by using a special-purpose digital computer to combine the outputs of 6 analog pitch indicators. The synthesizer uses spectral flattening to reduce spectral distortion caused by pitch variations and nonuniform filter bandwidths. For high-quality speech input, the quality of the Lincoln vocoder is considered by many listeners to be comparable to that of a voice-excited vocoder.