DSP in Telecommunications: Hail the Talking Listening Chips

Today, we can speak over a mobile phone from anywhere in the world and any time. Telephone calls can be made from aircraft flying at the height of Everest and from a round-the-world yacht on the ‘dark side' of Antarctica. At the heart of this revolution in personal and mobile communications is digital signal processing (DSP), which has had the same kind of impact on modern industrialised life that the discovery of steam had on the first industrial revolution. The Internet relies on the availability of low-cost modem technology in virtually every PC. It would not be possible for international phone calls to take place were it not for network-based echo cancellers. There are more than a billion speech coders in circulation worldwide in mobile phones, and DSP has provided the basis for the enormous current interest in portable audio players and voice-over-IP. Emerging speech technologies such as text-to-speech synthesis and speech recognition are poised to provide much more natural and intuitive interfaces to make the next generation of consumer technology much more accessible to all people, whatever their background or ability.