Re: FM Carrier Recovery for AOA Calculation

[Michael Berman]

Marcus,

Thanks for the reply!  I apologize, the GR package is gr-aoa, not gr-music, and can be found here (https://github.com/MarcinWachowiak/gr-aoa).  The NOAA broadcast is a NBFM signal.  I am using 2 Signal Hound receivers (https://signalhound.com/products/bb60c/) with 2 antennas spaced on a beam.  Do I need to synchronize the 2 receivers with an external clock, or should they be fine free running independently?

Thank you very much,

Michael Berman

On Fri, Sep 1, 2023 at 9:25 AM Marcus Müller <mmueller@gnuradio.org> wrote:

Not familiar with the details of NOAA signalling, but isn't the carrier of an FM signal
*the FM signal*?

For a DoA estimate, you'd correlate the different receive chains with each other to get a
phase; so, as long as the signals do have some bandwidth that makes the problem less
ambiguous, it'd work with any signal. I'm sadly not familiar with gr-music (and can't find
it on cgran.org), but MUSIC works as long as the signals at the different receive antennas
are correlated and noise is not. You do not have to preprocess your FM signal!

Best,
Marcus

On 01.09.23 17:09, Michael Berman wrote:
> Does anybody know if there is a way to recover a carrier of an FM signal to use for an
> Angle of Arrival calculation?  I am using GNURadio and gr-music and I am trying to use the
> NOAA Weather Radio signals.
>
> Thank you very much,
>
> Michael Berman