transmission technologies

   Transmission technologies are the electronic means by which communications are sent and received. Historically, communication transmission technologies in Britain have been developed and used in two specific ways: for telecommunication or point-to-point communication, and for broadcasting or one-to-many communication. British Telecom, as it is now known, developed transmission technologies to allow interactive twoway voice communication between any part of its network. The broadcast media developed transmission technologies that allowed a similar service to be delivered to many, over a large geographic area; it was thus non-interactive and one-way. However, current developments in transmission technologies, both software and hardware, are blurring this divide.

   For most of the twentieth century, transmission technologies have been of the analogue type. This form of technology creates and transmits signals that are analogous or similar to the original source. Hence, for example, music, which exists as sound waves is picked up and then converted into radio waves for transmission; once received it is converted back into sound waves. Currently, analogue technologies are being replaced by digital technologies which, for some, signal a revolutionary jump in communication technology. By digitalizing data —converting data, voice, text, graphics and video into a binary form—intelligent software can process, manipulate, compress and prepare the signal for transmission. At the receiving end this processes is reversed, turning the digital signal back into an analogue form that can be viewed, read or heard. Digital technologies will allow a huge increase in the number of channels that can be offered, an improvement in the technical quality of these services and the forms that they take will increase. For example, BSkyB will be offering hundreds of satellite delivered broadcast, narrowcast and interactive digital television channels after the millennium.

   Alongside digitalisation there have been developments in the hardware used: fibre optic, satellite, cable, cellular radio and microwave. While initially such developments reinforced the dichotomy of telecommunication and broadcasting, they are currently helping to redefine the boundaries. For example, as the power of satellites has grown, so their original use for point-to-point communications has been supplemented with the development of direct to home broadcasting (DTH). Thus in Britain, telecommunication bodies are starting to offer various new information and media-styled services, while the media is beginning to be involved in interactive twoway services (for example, cable systems are also providing telecommunication services).

   See also: cable and satellite

   Further reading

    Negrine, R. (1994) Politics and the Mass Media in Britain, London: Routledge.

   PAUL RIXON