Re: Correlation Estimator block threshold settings in Absolute/Dynamic mode

[Fabian Missbrenner]

Thank you for your help, Nick, Christoph, and Achilleas!

@Christoph
> How close to 1 did you use thresholds for the relative threshold method?
> For the relative threshold method I use thresholds between 1-exp(-5)
> .. 1-exp(-8).

Even with 1-exp(-15) I get many false positive detections. And it
seems to get worse over time. The longer the flowgraph runs, the more
false positives are detected. I guess that somehow has to do with the
way that the threshold is updated in the relative mode? But that's
speculation..

@Nick
> The magnitude of the correlation depends on the magnitude of your signal. The 
> AGC normalizes the signal amplitude before the correlator, so you see 
> expected behavior. The correlation estimator block expects the input to have 
> a normalized amplitude.
@Achilleas
> This means that if one wants to build a correlator that works with an 
> arbitrary scaling "a" (suppose a genie gave you that at the Rx), the only 
> thing you should have to do is to
> put as the parameter "threshold" in the block the quantity "a fraction".
> This would make the whole system transparent: no matter what the scaling is, 
> your estimator would work exactly the same.
> HOWEVER, as it turns out the "correct" scaling that works for this block is 
> to set  "threshold= a^2 fraction".
> This is really weird and I do not see any intuition behind that type of 
> scaling...

As genies are currently busy with forecasting the Covid-19 situation,
I'll stick with an AGC3 block prior to the Estimator. ;-)

Best regards
Fabian