culater33 ~ Excellentee' - my comments.
They got the frequency allocations ... And compression technology not lagging anylonger. Note the iboc codec ability to be sandwiched between AM/FM buffer allocations - very nice.
S-Band ... told ya tin.
''At the time, the technology for compressing packets of digital music and voice—and transmitting them from orbiting satellites 23,000 miles above the equator to cheap little receivers on the ground—was barely on the drawing-board. But two companies with a little imagination and a lot of cash snapped up chunks of the spectrum being offered in the newly available S-band (around 2.3 gigahertz). American Mobile Radio and CD Radio paid the FCC $80m each for the rights to rain digital entertainment from the heavens. American Mobile Radio became XM and CD Radio became Sirius.''
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ok - note here they equate the proprietary algorithms as MP3, base on Experts Group theme, similar technology, why, because it's in essence a poor codec, algorithm reserved for news and talk radio.
bit-rate = codec = AAC and tPac = CD quality.
XM won't even revel it, but we know, right ck.
All four satellite-radio firms—XM, Sirius, WorldSpace and Global Radio—employ similar technology to deliver their service. Music or spoken programming is first compressed using proprietary algorithms based on the Movie Picture Experts Group Audio Layer-3 (commonly called MP3). This lets broadcasters cram dozens of channels into a thin slice of bandwidth. After scrunching the audio data, operators must also decide on a bit rate—ie, the kilobits per second (kbps) of data that each signal can carry. As with streaming audio over a telephone line to a PC, a low bit rate translates into poor sound. For commercial reasons, XM does not reveal its exact bit rates, but it confirms that it uses higher levels on music channels to ensure CD-like quality. News and talk, however, transmit at much lower bit rates. Ground stations then upload the signal—now packaged as 1s and 0s of digital signalling—to satellites. These bounce the signal earthwards to mobile or (in the case of WorldSpace) stationary receivers.
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Key to Edig' facilitating portables - IMO
Though the studios are impressive, the most critical component for digital radio is in the receiver. At its core is a set of chips whose job it is to reassemble multiple digital signals arriving at varying times from alternate directions. This chipset then decompresses the stream into clean, crisp audio. More than any other factor, the chipset defines the audio experience. A poorly designed chipset will corrupt the sound with pops, clicks or dead air.
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This 'Buffer' 's 4seconds of signal... analogious to, but not yet 'on-the-fly' like our 'write-back' will be capable of doing with data and its storage. We could be involded here - imho, or will be.
''The second circuit handles decompression and encryption. Relying on subscription-paying customers, XM, Sirius and Global Radio scramble their signals so that they cannot be heard free of charge. The second circuit also buffers four seconds' worth of incoming data, so that tunnels, underpasses or other blind spots do not hinder reception.''
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Hmmmm - This is interesting - Orbitational Achustic algorythmic multiplexing .... Beyond tPAC. lol
That is because, instead of limiting broadcasts to fixed bit rates, Sirius continually fine-tunes its audio quality—a practice called “statistical multiplexing”.
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As mentioned - 3Com may have faild, but TI/Maycom could be smacking at this with it portable internet radio...
And record it on the road :)
Some audiophiles will not wait that long. They will tune in to the Internet instead. At present, there are some 4,000 radio stations offering together more than 100,000 streaming audio channels online. However, the only way to enjoy such programming today is with a PC and a broadband connection such as DSL (digital subscriber line) or cable modem. But what if there was a wireless device that could tune into thousands of Internet stations, but small enough to fit in a mobile receiver?
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Unified because they both want/need the high quality codec's -
As part of a settlement to end litigation filed by Sirius in 1999, which charged XM with patent infringement, the two firms have decided to share various aspects of their technology—with the intention of developing a radio that will, one day, let listeners buy one receiver that can recognise either signal.
And Agere brings with it:
The second circuit handles decompression and encryption. Relying on subscription-paying customers, XM, Sirius and Global Radio scramble their signals so that they cannot be heard free of charge.
emit....
