Accession Number : ADD002008

Title :   Application of Simultaneous Voice/Unvoice Excitation in a Channel Vocoder.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Coulter,David C

Report Date : 02 Sep 1975

Pagination or Media Count : 7

Abstract : The patent describes an improved technique and apparatus for increasing the quality of voice transmission through vocoders, particularly channel vocoders. The vocoder is modified to permit the simultaneous transmission of both voiced and unvoiced portions of a speech sound by connecting the pitch source to the lowest channel at all times, and including an additional decision circuit to independently transmit the voiced/unvoiced decision. With this connection, it is possible to reproduce sounds such as the voiced fricatives which contain simultaneous voiced and unvoiced portions. In addition, the threshold for voicing can be adjusted for less sensitivity while providing for low level voicing such as nasal murmurs and voice bars associated with stop consonants, or plosive unvoicing.

Descriptors :   *Vocoders, *Patents, Excitation, Multiple operation, Speech, Reproduction, Quality, Signal processing

Subject Categories : Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE