What’s All This DAB Radio Stuff Anyway?Written by Ian Poole
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The sound compression uses techniques that conform to MPEG standards. Also radio transmission uses a form of signal modulation known as Coded Orthogonal Frequency Division Multiplex or COFDM. Here data representing sounds and other data to be transmitted is spread across a large number of close spaced radio signals. By spreading data over a wide frequency in this way whole transmission is less susceptible to noise and other forms of interference including fading and multi-path interference.
Multipath interference results when signals are reflected from objects such as hills and buildings and several signals from transmitter arrive at receiver, all at slightly different times because they have travelled over slightly different paths and have taken slightly different times to travel. For VHF FM this is a particular problem and often results in signal becoming distorted. DAB digital radio is able to combine all signals, and make overall reception more robust.
Naturally technology to enable all this to happen makes radio receivers more complicated. However improvements in integrated circuit technology in recent years have enabled required capabilities to be built into a radio for a reasonable cost. It is also expected to fall further as DAB becomes better established.
Summary DAB Digital Radio is a great improvement over analogue transmissions that are broadcast. Offering possibility of better quality audio, accompanying data, push button tuning and no requirement to re-tune when moving from one service area to next, it is certainly provides a considerable improvement over older analogue broadcasts. By offering all these facilities, it sets DAB digital radio in a position to take over as new form of broadcasting for 21st Century.
Ian Poole is an award winning writer and consultant on radio electronics technology. He is also editor at Radio-Electronics.Com (www.radio-electronics.com) an Internet resource of free information, data and articles.
Encountering the third generation of DVD formatWritten by Dana Scripca
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As for these two vying formats, both use a blue laser (contrary to red laser for DVDs). The blue laser has a shorter wavelength leading to finer signal markings on optical media. Moreover, a shorter wavelength, associated with advanced compression process, prompts a higher storage capacity. Whereas HD-DVD holds 30 gigabytes, Blu-ray holds 50 gigabytes on a double-layer disc.
Professional video industry is one of most prosperous. Not surprisingly, engineers and manufacturing professionals, producers, video and audio professionals, web developers, broadcasters, directors, DVD authors, editors, graphic artists, gather on annual worldwide electronics and digital video exhibitions to learn newly techniques, technologies, capabilities, advantages related to their industry. There are seven major exhibitions: DV-Expo, Mediacast, DVD Europe, DVD Replication Exhibition, DVD Summit - Midle East Asia, Media-Tech, Production-Show.
Dana Scripca writes for http://www.allportabledvdplayers.com where you can find more information about portable DVD players. Please feel free to use this article in your Newsletter or on your website. If you use this article, please include the resource box and send a brief message to let me know where it appeared: mailto: firstname.lastname@example.org