On Tue, 14 Aug 2007 05:23:55 +0000, numeric wrote:
I am designing a broadband radio with all decoders implemented in software.
So far I have developed AM, FM, SSB, CW and DRM (digital radio) software
methods for reception. I would also like to include iBiquity digital for the
AM and FM bands. My guess is that IBOC is a variation of OFDM transmission,
but so far the details seem deliberately evasive. Any one with more details?

I think that IBOC is headed for oblivion. Would like to see how it performs
before it dies. There are no commercial radios that I would want to buy for
HD radio, they all seem like a mind-numbing waste of money. My only interest
is a home brew software version integrated into a multimode receiver.

There are technical "white papers" on the Ibiquity website, but I don't
think they provide enough details to implement a decoder. As other
replies have indicated, they consider this proprietary. (I wonder if
there are enough details in the patents?) I suspect you're going to find
the only way to implement a homebrew IBOC receiver is to acquire an
evaluation chipset.

The White Papers confirm that OFDM is used. If I read it properly (and I
may well not) the FM scheme uses 180 subcarriers and the AM 108. (in both
cases in Hybrid Mode where the analog is still present. Both AM and FM
support a full-digital mode with more subcarriers.)