Votrax real time hardware for phoneme synthesis of speech

A real time phonetic voice synthesizer roughly the size of a small hi-fi amplifier has been developed. It accepts a string of phoneme commands, each consisting of 8 bits. 6 bits determine the phoneme uttered while 2 bits determine the inflection associated with that phoneme. The synthesizer contains an active filter network which simulates the transfer function of the human vocal tract. This analog network is excited by both voicing and fricative sound sources. The sound sources and the vocal tract filter transfer function are dynamically manipulated in response to the numerous phoneme command sequences to produce articulatory synthesis by rule.