HD Radio is encumbered by the lack of a published standard (it's all proprietary iBiquity stuff at the moment) and even after that standard gets published, there will still be IP licensing issues (iBiquity IP, the audio codec IP, etc)... Effectively, you'll be trying to make something with the same IP issues that prevent a DIY DD/DTS decoder from being built, but with a bunch of extra complexity attached to it (RF downconversion, OFDM demodulation, etc)
Though almost every commercial in-car/in-home HD Radio decoder is based on a chipset from TI - you might be able to find an evaluation board for it and hide it inside a nice case.
Personally, I have issues with patents and licensing and closed standards being used in public broadcast...
Though almost every commercial in-car/in-home HD Radio decoder is based on a chipset from TI - you might be able to find an evaluation board for it and hide it inside a nice case.
Personally, I have issues with patents and licensing and closed standards being used in public broadcast...
I'm working in this industry so I can't really say much without getting myself in trouble... but here's some info:dsavitsk said:
After HDTV took nearly two decades to come out, the NRSC/FCC learned a few things about patents. A completely closed standard *won't* find its way into any public broadcast system. Any resulting standard will end up being something like ATSC - building a "clean-room" receiver completely from scratch is perfectly legal and possible by reading the specs, but you'll probably pay software licensing costs whenever you buy a chipset or a library to do it for you - and most companies do the latter.
Right now the HD Radio standard is almost completely ready to go. All the low-level frequency usage, OFDM/QAM, forward error correction and other low level stuff... everyone involved is happy with it. It's a very good/robust system in this regard.
What everyone's concerned about is iBiquity's audio compression codec, HDC - it's a patent-and-licensing-fee-encumbered black box, it's old constant-bit-rate tech, and I personally don't like its sound. And unlike DRM or even DVD discs, there's no provisions in the standard to allow different codec types to be used - which is a badbadbad idea considering that audio codec tech is a very highly researched field nowadays and there's far better standards already... licensing aside.
OK, here is a newbie post. First off, I agree that standards suck when only one source is holding all the cards. I'm pretty sure they used to call that a "monopoly". Some one might want to look that one up. In this day of high power DSP built into every audio card of a PC, I have to beleive that a decoder could be designed is software in a relativily short time. Any one know of this being done yet?
For AM DRM, this already exists - http://drm.sourceforge.net/nofaz said:
However, an AM DRM signal has far less channel bandwidth than the 400KHz bandwidth of FM HD Radio. You'll need a much faster DAC for IF sampling than you can do with a soundcard.
It may be possible to do AM IBOC with a faster (96KHz) soundcard, but there's still the whole "lack of a specification" problem.
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