Re: [Discuss-gnuradio] FFT normalization issue: noise aliasing

[Fons Adriaensen]

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

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It's also a pipe-dream, founded on self-delusion, nerd hubris
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