Tuesday, November 4, 2008

Satellite Radio

You have probably been hearing a lot about satellite radio lately, and there is no doubt that you will be hearing even more about it soon. How does satellite radio really work?All satellite radio services have three things in common: the actual satellites, the ground repeaters, and the radio receivers. These components are used to broadcast the radio signal a customer hears after subscribing to a service. But each of these service providers (Sirius, XM and WorldSpace) utilizes a unique broadcasting system to deliver sound (radio signals) to the subscriber. For example, Sirius utilizes satellites that orbit the Earth in an oblong pattern. While this may seem irrelevant to the average listener, it's significant because Sirius' model makes it possible for satellites to reach higher in the sky and, thus, lose their signal less often than other providers do. XM, on the other hand, operates geostationary satellites that orbit the Earth in a synchronized pattern consistent with the planet's customary movements. Radio reception is attained and, to make it clearer, XM then uses a network of antennas that re-transmit the signal to avoid interruptions that have been known to occur near tall buildings, bridges or hills.

So know that we know how the radio signal itself is transmitted, when does the music get added to the mix? At the digital broadcast centers, where radio programmers are responsible for picking what song will be played when. These centers maintain music in both digital format and a CD format and often also have studio space where performers can be recorded and their sound transmitted, live. The extremely high quality sound that subscribers hear is made possible by a process called digital compression, a procedure in which algorithms (a set of rules developed to break down a problem, or process, into smaller, simpler steps) are used to squeeze as much sound as possible into the bandwidth available. Satellite radios are the only types of radios sophisticated enough to decode these signals, which is why a subscription is required and why you won't be able to access the same content through your everyday AM/FM dial. The exclusivity, quality of sound, popularity and commercial free features of satellite radio have all been key factors in making it possible for companies to offer satellite service at a reasonable price.

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