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The Really Easy Guide
... to choosing and using a large screen television
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by: Richard Morgan
The first official public television broadcast occurred in 1939, some 30 years after the technology that allowed for this broadcast and reception system was patented. More than six decades down the track television has become the most popular form of entertainment in our homes and perhaps the most insidious product of technology invented thus far and the focus of much of our home entertainment.
 In a short time we have gone from poky black and white screens with blurred images to colour image with sensational resolution and quality. The television is also the front end of other broadcast technologies such as cable television, video tape and, of course, DVD. It's these new digital techniques that are to a large extent driving this technology.
In fact, the broadcast format for television is itself changing - to digital and in a few short years, if everything goes according to plan, we will either need a digital television to watch the box (an expensive proposition at present), or attach a converter to our conventional television (a much more cost effective option).
It's also possible that, thanks to digital technology, in the not so distant future it will provide and interface option for the Internet.
In the early days picture tubes and screens were small so they could disguise the lack of picture quality. Today that type of tactic simply won't cut it, particularly with large screen and widescreen models.
Television pictures are actually composed of constantly moving (scanning) horizontal lines occupying the face of the screen. Australia has adopted a system called PAL which uses 625 lines to form a single image. These lines are formed by an electron beam striking a phosphor coating on the inside of the picture screen.
The lines aren't scanned one after the other, rather they are split into odd and even number lines, scanned alternately, then interlaced to form the picture 'snapshot'. Fifty of these flashes are created each second (the brain interprets this as continuous information) to create what we then see as moving images.
An intense electronic beam makes the phosphor glow very brightly to produce bright images and less brightly for dark image needs.
The scanning of the beam matches the scanning of the original scene, which is handled by a sensor in the television camera during recording or relay-broadcasting.
As the scanning lines become bright and dark and the layers in between are added an image is formed. The resolution of a television image is the ability to distinguish between light and dark lines close together - too close and the lines merge into grey.
Resolution varies with the scanning capability of the visual medium feeding the television; VHS tape has the lowest followed by broadcast, with DVD having the highest.
The definition of television can be improved by a variety of methods, with the most touted at present being 100Hz Digital technology. Put simply, this system uses computer memory to hold image flash information, then doubles the rate at which the image is flashed every second. More flashes mean better resolution, but its main benefit and that which it's renowned for is the elimination of 'flicker' (most noticeable in the quality of fast moving action).
All televisions suffer from a problem called dot crawl, which shows up along horizontal or diagonal edges of objects with contrasting colours such as, yellow adjacent to blue and looks like an escalator. It reflects the television's inability to separate the colour signal from the luminance (brightness).
The amount of dot crawl varies between televisions, but is more likely in those units with features that allow you to enlarge an image or magnify a part of an image.
Direct view television is the type we are all familiar with - the type where we look directly at the picture tube. Generally, these sets have the sharpest images, because of two factors: there's a single picture tube and the optimum alignment of parts in this system. The largest direct view television is around 95cm diagonal so if you want a larger picture you must opt for a projection television at the expense of some picture sharpness.
A large screen direct view model is affordable and is the best choice if you need sharpness and a big picture, but widescreen models are becoming more popular (and reducing in price) with DVD enthusiasts who watch movies in widescreen or anamorphic aspect.
Aspect ratio is defined as the ratio of the width of the television screen to its
height. Standard televisions have an aspect ratio of 1.35:1 (also referred to as 4:3). This means the screen is 1.35 times as wide as it is high. You could encounter an aspect ration of 1.78:1 (usually referred to as 16:9), which is slightly more rectangular in shape.
Technology aside, there are some important aspects of television operation and function that need to be looked at when choosing a set. And remote control is perhaps one of the real triumphs of television technology and one that has been adopted in other areas of consumer electronics. Nowadays, station switching, volume control and picture adjustments can usually be done with wireless handsets, while sophisticated remote controllers look like something out of Bladerunner!
With multiple components being controlled remotely it's not unusual to find several different controller handsets cluttering up the coffee table. This situation can be alleviated to a large extent with a learning remote controller which, with a few simple actions, learns the commands from your other controllers and replaces several handsets with one.
The thing about remote controllers is you should be able to use them without too much fuss. They should be comfortable to hold and the button labels easy to read, maybe with illumination for night use. Run-through the controls and see if you can adjust what you need to quickly and accurately (there's nothing more frustrating than hitting the wrong button).
Besides the usual channel selector and volume control, there will usually be other buttons for picture quality and the set-and-forget controls should be located away from daily use controls.
With the advent of DVD players and home cinema systems connection facilities have become very important in television sets. Even if you don't own a sophisticated cinema set-up you're likely going to connect a DVD player to the television and will want to use the separate video and audio connectors to get the best picture and sound possible.
A television's connection facilities comprise RF and composite video inputs and a higher quality video inputs such as S-Video or better still component video.
Visual aspects aside, there's a lot to be said for the sound of television sets which can be as important as the images when considering the total entertainment experience. DVD raises sound quality to a new level of performance, because it's digital and with a system featuring the latest surround processing systems home cinema really hoots along.
The obvious option here is to assemble a full home theatre system with surround sound speakers and subwoofer. But this may not be immediately possible, desirable or practical.
Most large screen sets feature stereo sound, some even feature pseudo surround sound in-built or additional amplification to attach surround speakers and the like. These add to the cost and their desirability is personal. You certainly don't need sophisticated television sound facilities if you own an outboard surround system.
Make sure the television's sound is as natural as possible. Turn the volume up and ensure the set doesn't sound too harsh. Male and female vocals are one of the best tests around because you can tell if they sound false or natural. Usually built in sound systems have limited power and performance capability though some sets are better sounding than others.
When choosing a large screen television there is some tried and tested advice that can take some of the frustration out of choosing a product.
Chose a well know and reputable brand and a model that suits your viewing aspirations (and hip pocket). The television system you'll need is PAL, but NTSC compatibility could be a handy feature.
The larger the screen size the better, but look at the viewable screen area, not the picture tube dimensions or cabinet size, and consider 68cm sets as the entry point for good DVD replay.
Flat screen technology can improve picture quality so you need to assess how flat the screen is and if it makes the picture better. There is a plethora of picture tube technology out there but the final test of this is how good the picture quality
The systems that go into generating the images you see.
Picture enhancement technologies should be judged on their appearance, not the marketing rhetoric. The same goes for anti-flicker technology. Also rate any special effects functions such as digital still picture and zoom as enhancements to your viewing?
Teletext onboard can give you captioning facilities and there is a bunch of programming options which you should use to assess their relevance of value to you.
Importantly, you should rate the quality of the broadcast image using local transmissions and DVD image quality. Here trust your eyes and if it looks good then it'll more than likely satisfy your needs.
Look at the remote control. If it has a learning capacity it can help alleviate remove coffee table clutter, but assess how really smart it is. Also, is it easy to use in a variety of ambient light conditions.
With regard to dimensions, make sure any set you chose will it fit cupboards, shelving and other storage options and that can you place a centre channel speaker on top of it with safety?
Most importantly, and after you've played around with it's features and facilities, the television you buy must be capable of generating images that are pleasing to your senses. If it does this, you're on a winner.
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