[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum
From: |
Jens Elsner |
Subject: |
Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum |
Date: |
Mon, 9 Mar 2009 08:45:12 +0100 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
> > From: Marcus D. Leech <address@hidden>
> >
> > Let's say I have an FFT output that's many, many, bins wide, and I want
> > to compress that information into a narrower display (let's say from 4M >
> > bins down to 1024 bins).
> >
> > My approach has been to sum up each set of [4M/1024] bins, and use that
> > as the final output.
> >
> > Marcus Leech
>
> I think adding FFT bins is the correct way. But, for me I always select the
> maximum in these bins. I'm not sure that this is right but it gives me a good
> look over my spectrum data.
Spectrum Estimation is not trivial - I highly recommend having a look at
"Introduction to Spectral Analysis" by Stoica and Moses. A mathematical
yet readable introduction.
To solve you problem in a mathematically way, you can use windowing
in the time domain with subsequent overlapping block averaging
(Welch's method).
Gives a good practical estimate. Code for GNU Radio is here:
https://www.cgran.org/wiki/SpecEst
Integrating the FFT bins is just fine, but you probably loose frequency
resolution that way (if that doesn't matter, just leave it).
Best regards,
Jens
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Firas Abbas, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum,
Jens Elsner <=
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Brian Padalino, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, John Ackermann N8UR, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Bob McGwier, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Frank Brickle, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Marcus D. Leech, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Bob McGwier, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Marcus D. Leech, 2009/03/09
- Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Frank Brickle, 2009/03/09
- Re: Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, rwmcgwier, 2009/03/10
- Re: Re: [Discuss-gnuradio] Correct method for "compressing" a power spectrum, Frank Brickle, 2009/03/10