Editing Vocoder (section)

{{Short description|Voice encryption, transformation, and synthesis device}}
{{About|the voice encoder|the dictation machine|Voice recorder|speech synthesis|Voder}}

[[File:Kraftwerk Vocoder custom made in early1970s.JPG|upright=1.15|Early 1970s vocoder, custom-built for electronic music band [[Kraftwerk]]|right|thumb]]

A '''vocoder''' ({{IPAc-en|ˈ|v|oʊ|k|oʊ|d|ər}}, a [[portmanteau]] of ''vo''ice and en''coder'') is a [[Speech coding#Categories|category]] of [[speech coding]] that analyzes and [[Speech synthesis|synthesizes]] the human voice signal for [[audio data compression]], [[multiplexing]], [[voice encryption]] or voice transformation.

The vocoder was invented in 1938 by [[Homer Dudley]] at [[Bell Labs]] as a means of synthesizing human speech.<ref>{{Cite patent|title=System for the artificial production of vocal or other sounds|gdate=1937-04-07|url=https://patents.google.com/patent/US2121142A/en |country=US |number=135416A}}</ref> This work was developed into the '''channel vocoder''' which was used as a voice [[codec]] for [[telecommunications]] for speech coding to conserve [[bandwidth (computing)|bandwidth]] in transmission.

By [[encrypting]] the control signals, voice transmission can be secured against interception. Its primary use in this fashion is for secure radio communication. The advantage of this method of encryption is that none of the original signal is sent, only envelopes of the bandpass filters. The receiving unit needs to be set up in the same filter configuration to re-synthesize a version of the original signal spectrum.

The vocoder has also been used extensively as an [[electronic musical instrument]]. The decoder portion of the vocoder, called a [[voder]], can be used independently for speech synthesis.