EP0059880A3 - Text-to-speech synthesis system - Google Patents

Abstract

A text-to-speech synthesis system receives digital code representative of characters from a local or remote source, and converts those character codes into speech. A set of allophone rules (16) is contained in a memory and each incoming character set is matched with the proper character set to describe the sound of that particular character set. A microcontroller (17) is dedicated to the comparison proce­dure which provides allophonic code when a match is made. The allophonic code is provided to a speech producing system which has a system microcontroller (11) for controll­ing the retrievel, from a read-only memory (12), of digital signals representative of the individual allophone para­meters. The addresses at which such allophone parameters are located are directly related to the allophonic code. A dedicated microcontroller (13) concatenates the digital sig­nals representative of the allophone parameters, including code indicating stress and intonation patterns for the allophones. The allophones are divided into a plurality of frames with one digital position indicating whether the frame is the last frame in the allophone, in which event an extra frame is introduced to provide smoothing between allophones when no stop is present and when the present allophone is voiced and the subsequent allophone is voiced, or when the present allophone is unvoiced and the subse­quent allophone is unvoiced. A linear predictive coding speech synthesizer (14) receives the digital signals and provides analog signals corresponding thereto to a loud speaker (15) to produce speechlike sounds with stress and intonation.