Electrical Synthesizer of Continuous Speech

An electrical speech synthesizer controlled by teletype equipment is described. The basic components of the synthesizer are four simple tuned circuits each of which represents one of the resonances of the human vocal tract. The resonant frequencies of three of the tuned circuits are set by relay circuits that are controlled by data coded on punched tape. The punched tape also controls the intensity and pitch of a buzz generator that excites the variable tuned circuits, and modulates a noise generator that is filtered in various ways to generate fricative or stop consonants. The coded data are read from the tape at about the phonemic rate, with a rate of information transmission of about 35 bits per second. Smoothing circuits are incorporated in the synthesizer to provide smooth formant transitions between sounds. The generation of individual sounds, words, and sentences by the synthesizer is demonstrated.