Speech bandwidth reduction

The current state-of-the-art in techniques for reducing the bandwidth needed to represent the human voice waveform is reviewed. If techniques exist for significantly reducing the 3 KHz bandwidth while maintaining sufficient quality, the radio frequency bandwidth could be proportionately reduced. The status of speech baseband compression is still in the laboratory stage or just emerging. None of it has been applied in any large commercial operation. Technology is available for reducing the 3 KHz voice bandwidth by a factor of 10, but at this stage this technology is not useful because a desirable level of performance and cost have not been achieved. The basic conclusion is that techniques currently available for significantly reducing speech bandwidth produce a concomitant degradation in speech quality.