Buyer's Guide

High-definition (HD) or standard-definition (SD)??

The new family of plasma and LCD flat screen TV.s are available in both “high-definition” (HD) and “standard-definition” (SD) formats. Both use digital signals inputs but deliver different standards of picture quality. The HD TV picture quality is better than SD TV, and is achieved by using a much greater number of “lines” to construct the picture. HD pictures will comprise 720, 768 or 1080 lines compared to the 480 or 540 of SD television, thus offering better-than-DVD quality with an improved 3-dimensional quality.

The excellent picture quality of the HD screens, means that one can have a larger screen and/or sit closer to it without seeing the “fuzziness” of the picture. So HD is better and 1080 lines are better than 768. You will now see the term “Full HD” or “Full HD 1080” on some units and this refers to the higher number of pixels of the 1080 horizontal line screen.

It is fundamental to understand that the final picture is only as good as the combination of the input quality of the signal and then the screen’s capability to transform this into a picture. In other words, to get an HD picture, one needs an HD input AND an HD screen.

There are currently two sources for HD signals to input to your screen. TV transmission itself, which began to appear in the UK from 2006, becoming available first on Sky and Virgin Media when used in conjunction with the new HD-compatible set-top boxes, these transmission methods were followed in 2008 by Freesat again in conjunction with a set top decoder although some manufacturers like Panasonic integrated the decoder into the television. It is important to note that by 2012, analogue programming will be phased out and all homes will require a digital tuner. Secondly, inputs can be supplied by a Blu-ray system or games consoles to view films at home.

Historically, in order for a television to get the “HD-ready” badge from the European Information and Communications Technology Association (EICTA), it must have the following:

• At least one HDMI or DVI socket, which supports high-definition signals (HDCP) and also input(s) for video.
• A screen with at least 720 horizontal lines of pixels
• The capability to handle PAL (60Hz) and NTSC (50Hz) versions of the 1080i and 720p high-definition formats.

To appreciate the extra quality of a High Definition signal, we recommend plasma screens with a resolution of 1024x768 (XGA) and above, and LCD screens with a resolution of 1366 x 768 (WXGA) and above. To use with an HD DVD system, you must have 1080 horizontal lines to get the benefit. To use with a Blu-ray system, you must have 1080 horizontal lines to get the benefit.

Size of screen??

The first point to recognise here, is that because the flat screen TV inherently has less depth as a “box”, it is natural for most people to push it further back to the wall, resulting in the screen being further from their seating area than their old cathode ray tube type TV was. This in effect makes a flat screen TV picture with the same size screen as the old TV appear to be smaller!! Generally not the intention!!! The other consideration is whether you intend to buy an SD or an HD standard screen. Due to the better picture, it is possible to have a bigger HD screen than SD as you can sit closer to it without suffering a “fuzzy” screen. The table below gives the recommended screen size dependent on the distance of the seat from the screen and the screen’s definition.

LCD or Plasma??

This really is the BIG question!! Plasma is the older, more developed technology but in many areas still provides a better picture than LCD. For shade range, contrast range, colour tones, motion handling and usable viewing angle, plasma comes out on top. It is also the only technology that can make truly large screens of say 65 to 102 inch size, although LCD technology is catching up on this. Plasma is also typically cheaper for the same size screen. So why consider an LCD at all?? Plasma can suffer from “screen burn” when a picture/logo is static for a long time. This can cause a permanent shadow on the screen. Plasmas are also heavier than LCD and this could be an issue when wall mounting a large unit on the wall. Finally, plasmas are generally considered not as good for computer graphics nor can they currently go beyond a 1920 x 1080 pixel standard.

The conclusion is that for large screens above 55 inches there is more choice in plasma and above 60 inches, plasma is normally better value. Overall, you should consider the above limitations, especially the computer input and for 55 inch or above, while below this size, there is now a wider range of LCD models to choose from, and with refresh rates at 50hz, a 100hz and 200hz available LCD are more than a match for Plasma

Sound??

All flat screen TV.s now feature nicam stereo. Some have a built-in Dolby Pro-Logic (DPL) processor, which enables you to enjoy cinema surround sound at home. DPL uses four separate audio channels: front left, front right, centre, and rear. The separate rear speakers should be placed behind the viewing position. Some systems even have cordless rear speakers. The effect of DPL is that "being there" experience of feeling like you are in the middle of the film's action. A DPL TV is not the only way to enjoy surround sound. You may choose instead to buy one of the many Dolby Pro-Logic hi-fi systems into which you can plug your nicam TV. Alternatively, you could opt for a dedicated DPL amplifier to plug your TV into. Whichever option you prefer, remember that a nicam stereo TV is a pre-requisite to all of them, without nicam there can be no DPL. Another feature to look out for is Digital Surround Processing (DSP) or Pseudo Surround which is available on some DPL TVs. DSP enables you to enjoy pseudo surround sound on a soundtrack that was not recorded in DPL. The new generation of cinema sound is Dolby Digital Surround which uses six independent digital audio channels. Dolby Digital sound tracks are only available on DVD films.

Picture features??

All TVs flicker but we don't notice the flicker because TVs have a screen refresh rate of 50Hz. This means that the on-screen picture is replaced 50 times a second. The trouble is that once a TV screen gets larger than about 28", the flicker may occasionally start to become noticeable. To combat this, manufacturers have started producing 100Hz and 200Hz TVs which refresh the picture 100 or 200 times a second, making the flicker undetectable to the naked eye.

Integrated tuner (IDTV)??

Most TV.s now come with an integrated tuner, either in analogue format, digital format or some have both. However some still have no tuner and are in effect only a display. Currently, digital TV is being broadcast terrestrially, through satellite, and via cable. To enjoy digital TV you will either need a digital set-top box, which you can plug in to your existing analogue TV, or you can purchase an integrated digital TV (IDTV). Set-top boxes are available for digital satellite (Sky, Virgin Media etc) and for digital terrestrial (OnDigital, Freeview etc) services.

Connectivity??

Blu-ray

Blu-ray technology (see glossary) appeared in 2007. To gain the optimum quality from these ultra high definition sources, an HD screen of at least 1080 pixels is required.

HD Games Consoles

Microsoft’s Xbox 360 outputs 720 pixel graphics, with 5.1 surround sound, whilst the newer Sony PlayStation 3, provides the even better 1080 pixel graphic standard and will play Blu-ray discs.

HDMI (High Definition Multimedia Interface)

A High Definition Content Protection (HDCP) compatible HDMI socket is the officially supported method of connecting a high-definition signal to a screen. HDMI supports all formats of uncompressed high definition signals, and also boasts the capacity for 5.1 surround sound audio. An HDMI socket is a small rectangular shaped slot.

HD DVD and Blu-ray

At the end of 2006, HD DVD players arrived in the UK. These high capacity discs are able to store films in a high definition format. Blu-ray is a similar technology but with a higher disc capacity appeared in 2007. To gain the optimum quality from these ultra high definition sources, an HD screen of at least 1080 pixels is required HD Games Consoles Microsoft’s Xbox 360 outputs 720 pixel graphics, with 5.1 surround sound, whilst the newer Sony PlayStation 3, provides the even better 1080 pixel graphic standard and will play Blu-ray discs. HDMI (High Definition Multimedia Interface) A High Definition Content Protection (HDCP) compatible HDMI socket is the officially supported method of connecting a high-definition signal to a screen. HDMI supports all formats of uncompressed high definition signals, and also boasts the capacity for 5.1 surround sound audio. An HDMI socket is a small rectangular shaped slot.

DVI (Digital Visual Interface)

DVI is a digital connection standard, used on PCs with compatible video cards to provide an entirely digital signal from PC to monitor, without the need to convert it to analogue and then back to digital. An HDCP compatible DVI socket is the 2nd supported means of inputing a high-definition signal into a television. It provides the same excellent picture quality as HDMI, and can be connected to an HDMI socket by way of a DVI-HDMI connector. DVI does only carry the video information, however, requiring a separate connection for audio. DVI sockets are small, white rectangular sockets with a varying number of pins depending on the DVI type.

RGB Scart

RGB Scart, as the name implies, splits the picture into its constituent Red, Green and Blue parts, which are also the three primary colours televisions use to display pictures on the screen. This provides excellent picture quality, and is recommended for connecting screens to Sky, cable and Freeview boxes, as these devices normally feature an RGB Scart output as standard. SCART sockets are rectangular shaped 21-pin sockets and carry both picture and sound.

Component

DVD video is normally stored in Component format, where the video signal is split into 3 parts: 2 colour and one black/white. Component is therefore the recommended connection for linking a DVD to a screen, as no conversion of the signal is required. Picture quality is excellent both for DVD use and connection to other devices. Component cables come in either RCA (phono) or BNC socket types. The video sockets are normally coloured blue, green and red.

S-Video

S-Video is a good choice for devices where component connection is not available, and is widely found across a large number of products. Picture quality is still of a high standard, as the video signal is separated in two parts, compared to the 3 of component or RGB signals. An S-Video socket is distinguishable as a circular mini-DIN connector. Note that an S-Video signal can also be sent by SCART in many cases.

Composite

If the device being used supports neither component nor S-Video, composite represents an alternative which remains widely used. The video information is combined into a single signal, which does lead to some deterioration of picture quality, but is still in common use with VCRs, where composite is the standard recording format. Also known as CVBS, composite is normally a single RCA socket coloured yellow, with red and white sockets providing audio through separate channels.

PC Analogue

A number of LCD and Plasma screens are also designed to be connected to PCs for display purposes, and feature a standard analogue PC socket as a result. This standard socket found on most PC monitors for easy connection, and is also know as VGA or 15-pin D-Sub.
 

Co-axial Terminal: allows digital audio connection between two units, such as a DVD player and a Dolby Digital decoder or Dolby Digital TV.

Digital television broadcasting: the use of digital, as opposed to analogue, technology in the broadcasting of TV signals. Digital TV delivers an exceptionally high standard of picture and sound quality, whilst also enabling more channels than ever before to be broadcast at any one time.

Dolby Digital surround: the new generation of home cinema surround sound. Dolby Digital uses six independent channels of digital sound comprising: stereo front left and right; centre; stereo rear left and right; and a dedicated super woofer.

Dolby Pro-Logic surround: the established surround sound format, comprising four audio channels of sound: stereo front left and right; centre; and mono rear. The system uses five seperate speakers: front left, front right, front centre, rear left, and rear right.

Digital Surround Processing (DSP): also known as Pseudo Surround, it enables you to enjoy surround sound on a sound track that was not recorded in DPL.

Floor stand: also known as a cabinet stand depending on the design, this type of stand is common with CRT televisions, but is also found on some LCD and Plasma models, and allows the television to be stood on the floor. Floor stands often incorporate shelves, for placing DVDs and other devices on, and in may feature doors on the front, allowing a tidier looking finish.

Full HD: high definition screen with at least 1080 horizontal lines, producing the best picture standard currently available, assuming it has an HD input.

HD DVD: High Definition/Density Digital Versatile Disc is an obsolete high-density optical disc format for storing data and high-definition video. HD DVD was designed principally by Toshiba, and was envisaged to be the successor to the standard DVD format. However, in February 2008, Toshiba abandoned the format, announcing it would no longer develop or manufacture HD DVD players or drives.

MPEG2: an alternative digital surround sound system to Dolby Digital. Like Dolby Digital, MPEG2 also uses six independent channels of digital sound.

Nicam: CD quality broadcasting system for TV sound.

NTSC: the TV broadcast standard used in Japan and the USA.

Optical Connector: a fibre-optic link providing digital audio connection between digital sources, e.g. between a DVD player and a Dolby Digital decoder or Dolby Digital TV.

Pedestal stand: also know as table-top stand, this type of stand is common with LCD and some Plasma screens and allow the unit to stand on an A/V stand or table top.

SCART Socket: a 21-pin cable connector socket that provides very high standard sound and picture connections between different AV equipment.

Screen resolution: resolution is an important factor when considering an LCD or Plasma screen or television. The resolution measures the number of pixels (or dots) that make up the picture horizontally and vertically, for instance 1024 x 768. The higher the resolution, the greater the detail that can be displayed, although in many cases the benefit will be noticed mainly with high-definition or PC signals, that can make the most of the extra number of lines. Common resolutions include: VGA (640 x 480), SVGA (800 x 600), WVGA (854 x 480), XGA (1024 x 768) - the recommended resolution for high definition television on plasma screens, WXGA (1366 x 768) - the recommended resolution for high definition television on LCD screens

SECAM: the TV broadcast standard used in France.

Screenburn: prevention system available on better plasma TVs

S-Video input: input socket for S-VHS VCRs and hi-band camcorders. It provides for a hi-band video connection that is able to deliver a sharper picture because the chrominance and luminance parts of the video signal are seperated in transmission. Chrominance carries the colour; luminance carries the brightness of the signal. By separating them, S-Video signals have reduced interference, thereby sharpening picture resolution.

Tuner: this allows television channels to be tuned in. There are normally two types of tuner, an analogue tuner which would tune in the 5 main terrestrial TV channels when connected to an aerial, or a digital tuner, which tunes in the 20 - 30 FREEVIEW digital channels. Some plasma televisions do not include a tuner as standard, or may feature an external tuner box.

Widescreen (16:9): screen shape that has an aspect ratio of 16 units (width) by 9 units (height), resembling that of a cinema screen. Digital TV will be increasingly broadcasted in this format.