Low‐Binary‐Data‐Rate Operation of the Formant Vocoder

One of the formant vocoder's principal promises lies in the more efficient encoding of the word information content of speech than can be achieved by the use of the more familiar channel vocoder. The consequence of this more efficient encoding manifests itself in the capability for encoding speech for binary‐encoded formant data at binary‐data rates potentially as low as 150 bits/sec. In this paper, various avenues of approach for achieving such low‐binary‐data‐rate transmission are explored for system operation at various data rates ranging from 150 to 1200 bits/sec. Results of recent laboratory tests are presented.