High definition televisions / HDTV have exploded in popularity in the last few years. If are considering in making the upgrade to the latest television technology and want brush on some of the terminology the sales person is going to use then this will help.

High Def Televisions are the inevitable upgrade from today’s analogue system. HDTV uses digital technology to transmit an enormous amount of information in the same amount of space as used for standard analogue TV, thus setting new standards in your viewing experience by offering exceptional picture quality.

A traditional television set uses 576 vertical lines to produce images on screen. Compare this to a High Definition Television set’s 1080 and you can begin to see just how much better HDTV actually is.

720p and 1080p - What is the difference?

720p stands for resolution of 1280 x 720 pixels and the "p" means that the picture is in a progressive scan format. The other HDTV resolution 1080p means 1920 x 1080 pixels.

Progressive scan is based on all the horizontal lines being shown on the screen at one time giving a smoother image. It is generally believed that a progressively scanned picture is more suited to fast moving images such as sports, whilst an interlaced format is more suitable for slower images like films and documentaries.

The term "high-definition" can refer to the resolution specifications themselves, or more loosely to media capable of similar sharpness, such as photographic film.

High Def Receivers

Sky Television launched HD transmissions early in 2006. To receive HDTV now you will need to purchase a High Definition Receiver and, if not already installed, a satellite receiver dish. Freeview High Definition or Freeview HD is a television service that a selection of HD channels via your existing TV aerial and is due to launch in late spring 2010.

Are all digital TVs HD?

No. Digital TVs, commonly referred to as IDTV, are capable of receiving ‘standard’ digital signals and, while noticeably different to an analogue signal, it is not High Definition. Some HD-ready sets are, however, IDTV and capable of picking up the digital signal currently broadcast on ‘Freeview’. HD-ready televisions can also receive Freeview or Sky digital by the using a set-top box.

What are HDMI, DVi and HDCP?

Both High Definition Media Interface (HDMI) and Digital Video Interface (DVi) are connection types used to connect your source - whether it’s a set-top box, Blu-Ray DVD, HD DVD etc. - to your HDTV. Both HDMI and DVi offer high-bandwidth connectivity capable of carrying the HD signal to the TV.

Already widely used, HDCP (High-bandwidth Digital Content Protocol) is the copyright protection that helps to protect against unauthorised recording of HD content. Both HDMI and DVi support HDCP.

What is DLP?

Digital Light Processor (DLP) creates a very high quality projected image by the use of millions of little mirrors, one for each pixel. DLP is widely used in rear projection or front projection units and can be HD-ready.

I want an HD Television but how can I be sure I’m buying the right set?

Products displaying the HD-ready logo have been officially recognised by the European standards association (EICTA) as having all the requirements to receive and display High Definition TV programmes.

Colin McDonald is writing on behalf Euronics - Experts in High Definition Televisions