Escaping the System Control System

A vocoder (a portmanteau of voice and encoder) Is a category of voice codec that analyzes and synthesizes the human voice signal For audio data compression, multiplexing, voice encryption, voice transformation, etcetera Multiplexing Voice Encryption Voice Transformation Etcetera The earliest type of vocoder, the channel vocoder, was originally developed as a voice codec for Telecommunications applications in the 1930s, the idea being To code speech in order to conserve bandwidth for transmission In the encoder, the input is passed through a multiband filter Then each band is passed through an envelope follower And the control signals from the envelope followers are transmitted to the decoder The decoder applies these (amplitude) control signals To corresponding amplifiers of the filter channels for re-synthesis Multiplexing Voice Encryption Voice Transformation Etcetera Multiplexing Voice Encryption Voice Transformation Etcetera Since these control signals change only slowly compared to the original speech waveform The bandwidth required to transmit speech can be reduced This allows more speech channels to share a single communication channel Such as a radio channel or a submarine cable 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 Multiplexing Voice Encryption Voice Transformation Etcetera Multiplexing Voice Encryption Voice Transformation Etcetera 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 Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System Welcome to The System Control System