Every time an analogue video signal is transmitted, amplified, recorded or edited, the resulting
picture gets a little worse. Communication experts have long known that by converting the complex
analogue wave into simple digital pulses the signal can be regenerated many times without this
deterioration. In recent years digital technology has been applied to television. Among the most
common applications have been in broadcast production, long distance transmission of network feeds,
and a variety of consumer formats. Digital formats tend to provide a crisper picture, stereo or
multi-channel sound, and a wider selection of program materials and supplementary information.
All depend on compression software that reduces the amount of data that must be transmitted
In 1997, Canadas two direct-to-home satellite services began beaming digital signals to subscribers.
They were followed by cable operators, who offered digital as an enhancement of their regular analogue
services. In both cases, operators offered a wider selection of specialty channels as well as
pay-per-view movies. At around the same time Canadians began to purchase DVD (digital versatile disc) players that
played back programming stored digitally on a shiny plastic disc resembling an audio compact disc.
Also in the late 1990s, manufacturers began to sell digital camcorders that offered the additional
advantage of editing on a personal computer. The Museum has examples of a DVD player (20000006)
and the set top boxes required to decode digital satellite and cable signals for a conventional
television (20000014, 20000016).
|DVD players like this JVC model (20000006) play back digitally recorded video signals, ca 2000. (CSTM/Peter Lindell)||
|Scientific Atlantic set top box (20000016) decodes digital cable television signals, 2000. (CSTM/Peter Lindell)|
The video field is currently experiencing a great deal of technical change. New digital
technologies like high definition television (HDTV), flat panel displays, home theatre,
and video on demand have recently been introduced to consumers. The adoption of digital
format opens up numerous possibilities for treating video signals like any other form
of data. Video signals are routinely combined on radio and fibre optic communication
channels with other forms of information. Broadcasters and home video buffs perform
editing at computer work stations. Users of DVD players access additional information
on the program they are watching by pressing a button on their remote control.
Subscribers to digital television services can browse program guides or order
up movies just as readily. With the proper decoder and keyboard, they can convert
their television into a terminal for accessing the Internet. Conversely, a personal
computer user with a high speed Internet connection can view and even record high
definition video signals. At this time it is not clear how this technology will
evolve or how widely it will be adopted. While digital systems present certain
opportunities that are eagerly anticipated and adopted by technophiles, most
Canadians can be expected to make a more measured assessment of their needs
and their financial means. As the picture becomes clearer, the television
collection of the Canada Science and Technology Museum will
evolve to reflect it.