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Re: [Discuss-gnuradio] FFT normalization issue: noise aliasing
From: |
Fons Adriaensen |
Subject: |
Re: [Discuss-gnuradio] FFT normalization issue: noise aliasing |
Date: |
Sun, 15 Oct 2017 14:42:24 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Sun, Oct 15, 2017 at 02:03:15PM +0200, Jean-Michel FRIEDT wrote:
> Shouldn't my aliasing experiment raise the noise floor rather than keep it
> constant ?
By taking only every 10th sample, you also reduce the sample rate
by a factor of 10. So you have the same power in 1/10th of the
original bandwidth. In other words, noise power per Hz has
increased by a factor of 10. This noise density (compared to
signal power) is what matters in e.g. demodulation.
Ciao,
--
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
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- [Discuss-gnuradio] FFT normalization issue: noise aliasing, Jean-Michel FRIEDT, 2017/10/15
- [Discuss-gnuradio] FFT normalization issue: noise aliasing, Marcus Müller, 2017/10/15
- Re: [Discuss-gnuradio] FFT normalization issue: noise aliasing,
Fons Adriaensen <=
- Re: [Discuss-gnuradio] FFT normalization issue: noise aliasing, Jean-Michel FRIEDT, 2017/10/15
- Re: [Discuss-gnuradio] FFT normalization issue: noise aliasing, Jean-Michel FRIEDT, 2017/10/15
- Re: [Discuss-gnuradio] FFT normalization issue: noise aliasing, Marcus Müller, 2017/10/16