voice-coder. A device that usually consists of a speech analyzer, which converts analog speech waveforms into narrowband digital signals, and a speech synthesizer, which converts the digital signals into artificial speech sounds.
Vocoder is an acronym for voice coder/decoder. A synonym is software codec. This is the term given to the process of encoding and decoding voice using an algorithm implemented in software and/or hardware. The process is often referred to as voice compression and decompression. Common vocoder algorithms are G.711 (PCM), G.723.1 (used by Microsoftâ€™s NetMeeting), G.726 (ADPCM, used by the NACT STX switch/IPAX gateway for voice message playback), G.728 and G.729. This function is usually performed by hardware or DSP software.
An audio effect that produces "robotic" sounding results when processing vocal input. It uses an algorithm called ring modulation to produce the effect. Examples can be found in some disco and modern music, such as the Beastie Boys' "Intergalactic".
A vocoder (name derived from voice encoder, formerly also called voder) is a speech analyzer and synthesizer. It was originally developed as a speech coder for telecommunications applications in the 1930s, the idea being to code speech for transmission. Its primary use in this fashion is for secure radio communication, where voice has to be digitized, encrypted and then transmitted on a narrow, voice-bandwidth channel.