Re: [Discuss-gnuradio] DAB, RDS, DRM, HDradio and OFDM

[Eric A. Cottrell]

Martin Dvh wrote:
> Hi all,
> Is anybody working on DAB, RDS,DRM, HDradio or OFDM at the moment.
> I will probably be working on all of these in the near future and was 
> wondering what the status is of these and where to find what.
Hello,

I have some interest in IBOC.  iBiquity has some information on the
waveforms used.  Maybe a person like Bob can figure out the parameters.
http://www.ibiquity.com/i/pdfs/Waveforms_AM.pdf
http://www.ibiquity.com/i/pdfs/Waveforms_FM.pdf

The AM waveform seems a lot simpler to tackle.  The real fun will be
figuring out the data formats.  I assume that an IBOC receiver first
locks on the IDS data stream, or maybe a Reference since it is BPSK
modulated.  I have seen weak signals where a IBOC receiver can get the
call but can not go into full IBOC mode.  This makes me suspect that you
could receive the callsign without using OFDM.  After it gets the
service mode it then configures the receiver for OFDM.

I was thinking of doing a receiver that phase-locks to the AM carrier so
I can look at the I/Q output of a IBOC signal.  You can also use it as
the basis for a AM Stereo radio receiver.

73 Eric