From New Zealand Listener , June 1, 1985.
by Graham Ford
Our television sets, in many ways, belong to the past. The screen itself is reminiscent of the 1930s. But technology is developing so rapidly that by the year 2010 the humble "telly" will look nothing like the present "boy"
OUR TELEVISION SETS are grounded in 1930s technology. Their hearts, cathode ray tubes, resemble nothing so much as giant valves. The set works on simple principles: the inside of the screen is covered in a matrix of phosphorus dots, electric beams zip across the dots and every time a beam hits an appropriate dot it glows. The beams scan the dots in 625 lines, 25 times a second, forming the picture.
The screen itself is reminiscent of the 1930s. It has a width-to-height ratio of 4:3 recalling the shape of early films. Modern films range around a ratio of 3:1, which is more satisfying to the eye. Our television sets, in many ways, belong to the past. But technology is developing so rapidly that by the year 2010 the humble "telly" will look nothing like the "box".
Flatter screens: In Japan and Europe, "flatter" television screens are being introduced. At the moment TV screens have to be made of thick, curved glass. This is because there is a partial vacuum inside the tube and the screen has to be solid enough to resist the air pressure. A 66cm (26in) screen, for example, can have two-and-a-half tonnes pressing on it. However, improvements in glass technology have made possible "flatter" screens that are "squarer" in the cor- ners. Also the phosphorus film, on the inside of the screen, can now be shaped to a sharp point in the corners, rather than rounded as it is at the moment.
Cable television: Overseas, cable television has become popular. Here the signal transmission is carried by wire instead of over the air. In the United States 25 percent of families have cable, in Canada, 50 percent and in Belgium, 70 percent.
The average American cable system offers 12 channels. Cable's chief advantage is the large number of channels it can provide and because you pay for it by subscribing this can mean no advertisements. But it is expensive. In Britain cable is losing huge sums of money, and in America the cable boom is over with people returning to the main networks. Cable is really more suitable for areas of high density population like New York City, or the Netherlands, where economies of scale make it viable. It has been estimated that it would cost $65 million to put in underground cables for 100,000 homes in a New Zealand city. This high cost exacerbated by New Zealand's scattered population means cable will not be introduced in the short term.
Optical fibre: Optical fibre will add another dimension to cable television and telecommunications worldwide. Here thin, hairlike fibres of glass carry light signals generated by laser beams. Optical fibres can transmit vast amounts of information. The French are implementing this technology faster than anybody else and in New Zealand the Post Office has been trying it out. For television, where co-axial cable can carry about 50 TV channels, optical fibre could carry 400.
Satellite: Another way to increase the number of channels available at home is by Direct Broadcasting Satellite (DBS). TV signals could be beamed up from Warkworth and the satellite transmit them across the country where they would be picked up by metre-wide dishes on the roofs of houses. But power supplies on board satellites are limited - either batteries or solar panels. Because it has to broadcast a strong signal this restricted energy means that current satellites can only produce about five channels.
The main advantage of this system is almost 100 percent coverage of the country. Unlike the present land-based system it is not restricted by valleys or hilly terrain. Short of living in a cave or under a cliff, everyone ought to get it. Unfortunately, satellites are also expensive, costing about $200 million. In addition to the dish, each household would need "a little black box" to sit on top of the set and adapt the signal. The cost of adaptor and dish has been estimated at between $1000 and $2000. The British are planning to bring in a DBS and have become alarmed at the rapidly rising costs, so, like cable, it will be a long time before we see this expensive technology here.
Stereo sound: Television with stereo sound is now being introduced into TV sets in the US, Japan and West Germany. Not only does the sound quality improve, but also the sets are more attractively styled with speakers on either side of the screen. The Americans and Japanese have developed separate TV stereos suitable for the 525-line system. The West Germans have made one for the 625-line system. And the British are proposing yet another one for 625 lines, even more sophisticated, with three channels. While many broadcasting experts are excited about the proposal there is some doubt about the length of time it will take to get this system operating. So far Australia, the Netherlands and Sweden have adopted the West German stereo.
High definition: The Japanese are leading the research to build a high-definition TV. The screen would have 1125 lines and a much sharper image. Compared with a conventional one the new screen has five times the picture element density.
"The high-fidelity large screen shows up the crow's foot on the face of an actress," commented one Japanese engineer. Stage hands will not get away with shoddy settings. The improved image reception will require an entirely new approach in the production and contents of TV programmes." Hight definition TV would have many applications, for example, medical students on one continet could watch micro-surgury being performed on another.
Slim screens: It will be possible one day to hang a television set up on the wall like a picture and the set will only be centi- metres thick. Research is going on to develop such a television using liquid crystal displays similiar to those in watches and pocket calculators. The screen has myriads of little cells that are scanned like a conventional television. The Japanese have been able to make a two-and-a-half-inch liquid crystal TV. It will probably be another 10 years before the flat screen reaches the market.
These screens will have a new width to height ratio of 5:3 instead of the current 4:3. Research shows that 5:3 is much closer to that of normal human vision. The new-shaped screen also means that when films (ratio 3:1) are "adapted" for TV, less of the picture will have to be cut off to make it fit.
The slim screen will also make possible large TV screens in the home. But there is a distinct limit to size. You need eight times the horizontal distance of the picture to enjoy it comfortably. If you had a three-metre-wide TV screen you would need a room 24 metres long to view it!
Digital television: The ubiquitous siIicon chip has insinuated its way into television sets, and the transmission of the signal. At present television broad- casts are an "analogue" signal which indicates brightness, colour and so forth.
With the use of silicon chips a digital signal is possible, whereby picture in- formation is coded in a series of numbers and the set would interpret these and construct a picture. This form of trans- mission creates a clearer, sharper image. Digital technology can also be used inside the set. It will make manufacturing easier and also provide a number of special effects. With a fully digital system one would be able to "freeze" the TV picture, enlarge one section and zoom in on it, or show another channel in one corner. Digital electronics can also correct ghosting and other interference.
TV sets with some digital electronics are available on the market now. How- ever until the rest of the technology catches up they will not be able to offer all these other features. A technical magazine noted recently: "An analogue receiver correctly adjusted will give just as good a display and be a lot cheaper".
THE INTRODUCTION of these advances will not happen over- night. Many technical problems remain and there is also the urgent need for standardisation of world television systems. Another factor is the world economy. If there is another recession changes will take longer. The development pattern of technology is one of steady evolution, step-by-step. Flatter screens are coming in, along with stereo, digital is gradually appearing on the scene as are fibre optics. Then it will probably be new ratio screens, slim screens and high definition TV. Manufacturers are likely to be cautious and approach these changes gradually, be- cause of the vast capital investment required to test the market, and to see if the public is prepared to pay for these innovations.
But once technological momentum has begun it is hard to stop. One change tends to spark off others. There is a kind of web of technology where all the technological improvements are inter-related. One development cannot take place unless several others do so as well. For example, the introduction of fibre optics will vastly increase the quantity of information that can be transmitted. This advance will make the introduction of higher definition TV more feasible.
It will not be an overnight change but a steady one, where we, the consumer, dictate the pace. By the year 2010 the box will be a curiosity in a museum.
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