What’s All This DAB Radio Stuff Anyway?Written by Ian Poole
DAB digital radio is new medium for sound broadcasting. Now well established in many countries around world, new DAB radios are hitting market. While these new radios are still a little more expensive than those that receive older analogue AM and FM transmissions, they offer significant improvements that come with DAB digital radio.
Advantages Possibly most important advantage for listener is near CD audio quality that DAB can bring. Hiss and fading are now a thing of past. Not only is quality better but more stations can be accommodated within available space and this means that there is a much greater degree of choice.
Another important facility provided by DAB digital radio is its data capability. Data is transmitted alongside main audio and this can be displayed on a screen that many DAB sets have built in. This may be title of a song being broadcast, a plot summary for a play, up to minute sports results, or whatever broadcaster feels is appropriate. In fact some stations scroll news headlines across screen, or provide other useful free information including Electronic Programme Guides.
Not only does system bring many advantages for listener, but it also helps broadcaster. Lower power levels are required for transmitters. This saves considerably on cost of electricity. This is particularly important for large national networks like BBC and others. With transmitters often using 100 kW and more, costs for running these transmitters are very high. Also by reducing power consumed, it helps environment.
Another advantage is that DAB uses what is termed a Single Frequency Network. This means that all transmitters in same network use same frequency without interfering with each other. Currently a national network using VHF FM, for example, has to use a number of frequencies so that transmissions do not interfere. DAB Digital Radio does not need this and space needed for broadcasts is much less. This also brings another advantage for mobile listener because there is no need to retune receiver onto another frequency when moving out of coverage area of one transmitter into next.
Technology DAB Digital Radio works by converting sounds into a digital format. Once in this format they can be manipulated using digital signal processing techniques to compress and manipulate signal. Furthermore when signal is transmitted error correction techniques can be used to ensure that once data representing sounds is transmitted, it is received correctly at receiver.
Encountering the third generation of DVD formatWritten by Dana Scripca
It won't last too long until third generation of DVD format to be unveiled. Your DVD player will play a well-performing disc with high-storage capacity. The upcoming Media-Tech Expo, Las Vegas, USA, will surely clarify this topical issue.
The upcoming Media-Tech Expo May 10–12, 2005 in Las Vegas, USA will be a crucial moment in deciding what DVD format will be succesor of actual DVDs. It will be HD-DVD? Or Blu-ray Disk? Before end of 2005, more likely in 2006, standard format will be decided for good. The competition between HD-DVD and Blu-ray is in full swing now.
The overwhelming increase of portable DVD players led to a even higher rise of DVDs industry. In 2003, almost 4 billion prerecorded DVDs were produced. This number is calculated to increase to 7 billion in 2006. The same for recordable DVDs market: DVD±R, DVD±RW. While in 2003 just 908 million disks were produced, it is estimated a double growth rate in 2004 (and about 4 billion estimated in 2006).
This year edition, from Frankfurt, manufacturing technology for third generation of optical storage media has been debated. More than 1,400 people joined 2004 edition. At upcoming 2005 edition, concepts for replication lines and single components for manufacturing of HD-DVD and Blu-ray Disc will be introduced. Media-Tech Expo is leading annual tradeshow for media manufacturing industry.