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Digital revolutionizing radio, A digital extension to AM/FM radio
atici
post Jul 28 2005, 17:20
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QUOTE
Plug a set of headphones into a radio tuned to an FM jazz station. Hear the hiss at the bottom of the range and the fuzz at the top. Remember why you like compact discs.

But don't be impatient: wait eight seconds. An "HD" light appears on the tuner. And now the bottom drops out. The hiss turns to silence. The stereo channels separate, opening a cramped room into a performance hall. And the high fuzz is now crisp high notes from a trumpet or Ella Fitzgerald.

You have just heard terrestrial digital radio. Or you would have--if you could get your hands on a receiver.

Link to the c|Net article


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The object of mankind lies in its highest individuals.
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2Bdecided
post Jul 28 2005, 17:49
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QUOTE
Digital AM sounds like present-day stereo analog FM


LOL!!!!!!!!!!!!!!!!!!!!!

I've head the Digital AM samples. If FM sounded like that, I'd bin my radio!

I don't know how good USA Digital FM will sound - but if they're planning to cram "up to 5" stations into the bandwidth of 1 analogue FM station, it'll mean very low bitrates.

You guys should learn from the mistakes made in the UK - don't cripple digital radio with sub-FM sound quality.

Then again, the USA didn't allocate any "new" spectrum for digital radio - meaning that there's barely enough space to simulcast the existing station in digital. If you want to offer extra choice via digital FM, it will be at the expense of sound quality.
Welcome to the 21st century!

Cheers,
David.
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atici
post Jul 28 2005, 18:38
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I think the idea of digital radio sounds promising. But that would require the broadcasters adopt a new standard that has nothing to do with FM/AM but more like Wi-Max broadband.
QUOTE (2Bdecided)
If you want to offer extra choice via digital FM, it will be at the expense of sound quality.

Why so? If your receiver can't use the new channels that would increase the quality, it'd still receive the usual FM channel. Are you saying the station would lower the quality of the usual channel (because of the lack of spectrum) ?


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2Bdecided
post Jul 29 2005, 10:19
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The IBOC (in band on channel) system in use in the USA puts the digital signal right at the edges of the standard FM signal. It will add noise to the station (and its neighbours) under certain circumstances.

However, that's not what I was talking about. IIRC They can broadcast about 96kbps on top of each analogue FM station.

So if a broadcaster decides to deliver 2 digital stations, that's 48kbps each! 5 would be 19.2kbps each!!!

If you shut down the analogue FM station, you can get a higher datarate. I can't remember what it is, but I having a feeling it's about 200kbps still not enough for 5 CD quality radio stations, whatever the codec! (And whatever the marketing department tell you!)

Cheers,
David.
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