On-off Signals Research Articles

A Narrow Band Speech Transmission System Employing the Recognition of Phonetic Elements

In a companion paper, one of the authors discusses the automatic recognition of phonetic elements of speech by a device which continuously correlates the measured frequency spectrum of incoming speech with a set of reference spectra. After such recognition, one can transmit the resultant information over lines of very narrow band width for speech synthesis by a reverse process. In a circuit which has been built to study this method of transmission, the number of phonetic elements which is recognized is limited to ten, thus requiring transmission only of information as to ten on-off signals, between sending and receiving terminals, plus a narrow band channel for transmitting pitch information. This information is used to control hiss and buzz energy sources in a synthesizer which is similar to that of the vocoder. A demonstration of the operation of this system will be given using recordings.