My mistake ... my noise level was far too high. Additionnally, the noise
with amplitude lower than LSB must be added to a full-scale range sine wave
to be dithered amongst the various quantization bins. If anyone is interested,
I updated http://jmfriedt.org/quantization.pdf which (I believe) demonstrates
the impact of quantization on the noise floor.
JM
--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe,
25000 Besancon, France
February 16, 2020 5:36 PM, "jmfriedt" wrote:
> I wanted to demonstrate quantization noise (V_q^12/12/fs noise floor)
> with GNU Radio and somehow my demonstration is failing. I am trying
> http://jmfriedt.org/untitled.png (or http://jmfriedt.org/untitled.grc)
> following the chart of the Quantizer. Somehow I had already noticed
> that the Qt Freq Sync is displaying a spectral density (because keeping
> 1:N will not raise the noise floor by N as would be expected from aliasing),
> but here the noise is obviously quantized (see time domain) but the
> spectral density in the frequency domain does not show the impact of
> quantization.
> Is this expected ?
>
> Thanks, JM
>
> --
> JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe,
> 25000 Besancon, France
