I found this article in blogland. Its quite good in explaining the HD TV evolution, and the history of changes in televisions.
What is HD Satellite TV?
HDTV stands for high definition television. This is a higher quality television picture than the SDTV or standard definition television. High definition signals are available from paid television providers like Sky TV and other providers. The HD signal has a greater resolution than the SD signal, 1080i compared to 480i, which amounts to six times the resolution of the SC signal. The shape of the HD signal, when it appears on an HDTV screen, is similar to what is viewed on the screen in a movie theatre-much wider coverage that the old almost square format home television screen. The High Definition transmission also has three components to its signal, not one, like an SD signal. This results in less signal degradation and therefore greater clarity on your television. The HD signal is completely digital which also gives added clarity over the standard definition signal.
History of HDTV
The first publicly demonstrated television was given almost eight decades ago in England. From this first remarkable television demonstration of a grainy black and white image to receiving a high definition television signal beamed from twenty two thousand miles in space to a personal receiving dish has been a long road.
There are upwards of 270 million televisions in US households today. But it was not until 1949 that the sales of televisions began to rapidly increase. The first commercial color set was introduced by RCA in 1954 and by the time the 1960s set in most black and white televisions had replaced with color units. Also in the 1960s remote controls were introduced by the television industry to further enhance the television viewing experience. This was perhaps the one event that birthed the “couch potato” generation, not even having to stand up and move to change the television channel.
And then in the 1970s the VCR made its debut and freed the television viewer from real time viewing, allowing them to record a program and watch it when it fit into their schedule. In the 1970s and 1980s, cable television also became more mainstream as more channels came online, which today, exceeds 300 offered by the major paid providers. Beginning in the 1980s television began to become more of a central focus in the lives of Americans with the increased program offerings. A person at home could “view the world” and not even leave his or her living room. HD Satellite TV is just the newest advance in this 80 year old technology that has brought the world closer together and in some respects moved it farther apart. Television is wonderful at magnifying many of the problems that we need to solve in our world.
The present day HDTV signal began with research in Japan by the Japan Broadcasting Corporation. The research was taken up by the US in 1980 and the first HDTV demonstrations occurred in the US in 1981. In the mid 1990s it was suggested that that an all digital signal would, in the future, become the standard for television broadcasting. This mandate ushered in the widespread use of HDTV that we see today.
Both Sky TV and other broadcsaters are now providing quality, HD programming through satellite service and even on TDT in Spain – the terrestrial digital TV service available in Spain via a TV aerial.
HD Satellite TV Receivers
In order to take advantage of the new hd satellite tv signal, there are new hd receivers satellites are tuned to transmit to in dish satellite hdtv home systems. These receivers are hard wire from the satellite dish to inside your home entertainment center equipment. Improved models are constantly being designed so that more dish packages can be selected by hd television viewers. The present day DVR has almost totally replaced the VCR as the standard program recording device. Many VCR units are still around, but the newer Digital Video Recorders can record 500 hours of SD television programming. This is a remarkable increase over the 6 hour maximum of the old VCR tape.