Residents of both the USA and the UK can expect to be dealing with the digital switchover within the next couple of years. What this means is that region by region, analog signals (also known as terrestrial TV) will stop being broadcast and viewers will need to buy an HDTV (High Definition Television) in order to watch the new digital signals being broadcast.
The differences between analog signals and digital signals are quite stark. On a basic level, analog television screens fire a picture onto the screen a whole frame at a time. Digital television, on the other hand, either fires all the odd lines at one time followed by all the even lines (interlaced scan mode at a screen resolution of 1920 x 1080 pixels), or one line at a time (progressive scan mode at a screen resolution of 1280 x 720 pixels). To an untrained eye digital interlaced and analog scan modes have little differences. However, progressive scan modes do improve the quality and smoothness of motion.
The most commonly used digital television standard in the UK is Freeview, which provides a number of free digital channels with a set top box, though most new televisions now have Freeview built in. The latest development is Freesat, which provides Freeview via a satellite dish and additionally will provide a number of HD channels.
One of the main advantages of Digital TV for viewers is that broadcasters are able to embed digital data into the streams, such as program information and interactive channel menus (eg Press the red button now). This data is read and executed by a computer system in the television and made interactive via infra red on the viewer's remote control pad.
Another huge advantage of digital television is that digital data takes up less bandwidth, meaning more channels can be broadcast at the same time. This gives viewers much more choice in what they watch and allows for follow up channels which broadcast the same programs as their namesake, just an hour later.
With all television signals comes the issue of reception. The most common way to receive digital signals is through Digital Terrestrial Television, or DTT, where the binary code data is picked up via an aerial. Aerial signals, however, are subject to poor reception which results in a poorer quality picture and audio (eg blockiness) which is why there are alternative ways of receiving Digital signals such as through an optical / DSL cable (IPTV), via P2P internet connection , or via digital satellite. The main advantage with IPTV, P2P connection and digital satellite are that the signal is likely to be stronger, the binary code complete and therefore the picture and sound quality much better.
It is widely agreed that the audio and picture quality of Digital TV is a great improvement on Analogue TV, but this is not where the differences end. Viewers receiving Digital signals have the opportunity to receive more channels, interact with them and get a lot more out of their viewing. While it might seem that the team driving the Digital Switchover are giving the public little choice over how they watch television, it cannot be denied that the advantages of Digital TV hugely outweigh those of analogue and that the switch will benefit everyone involved.