Re: [Discuss-gnuradio] Phase unwrapping

[Michael Berman]

Daniele,

I have worked on this problem for a specific case as well.  I have a document with source code and a short description of what's happening that can be found here (https://www.dropbox.com/s/bcma7fqa7ip2own/unwrap_example.txt).

Michael

On Mon, Jun 16, 2014 at 10:05 AM, Daniele Nicolodi <address@hidden> wrote:

Hello Matt,

thank for your answer. I'm aware of the problem and in my application I
can keep phase bounded, but not bounded to (-pi, +pi]  therefore I need
unwrapping to make sense of my modulation data.

If such feature does not exist in GNU radio, I hope it is not too hard
to code it myself.

Thanks. Cheers,
Daniele

On 16/06/2014 15:44, Matt Ettus wrote:
>
> Daniele,
>
> The problem with phase unwrapping is that it is unbounded, and will tend
> to infinity.  Once it gets very big, when you try to add a small number
> to a very big number, floating point loses precision.  Eventually,
> adding small to extremely big returns the big number unchanged.  This
> isn't that useful.
>
> Matt
>
>
>
> On Mon, Jun 16, 2014 at 2:40 PM, Daniele Nicolodi <address@hidden

> <mailto:address@hidden>> wrote:
>
>     Hello,
>
>     I just started to work with GNU radio for my very basic needs, so please
>     excuse my naive questions and probably my inappropriate use of the
>     jargon.
>
>     My first trivial application of GNU radio is to simply measure the phase
>     of a phase modulated signal with an Ettus Research USRP N210 and a LFRX
>     daughter-board.
>
>     Everything works as expected, but I haven't found a way to do phase
>     unwrapping (removing the 2pi ambiguity in the phase obtained from the
>     arctan function looking at discontinuities in the phase data). Is this
>     functionality offered somewhere, and I missed it, or should I look into
>     implementing it myself?
>
>     Thanks. Cheers,
>     Daniele
>
>     _______________________________________________
>     Discuss-gnuradio mailing list

>     address@hidden <mailto:address@hidden>
>     https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

>
>


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