[subexp-daq] Question on NURDLIB - what is 'pedestal'?

[Håkan T Johansson]

Dear Günter,

that ought to be for ADCs or QDCs.  On the trigger they typically convert 
all channels.  But most are just noise.  Then the storage of values only 
happens if they are above the threshold.

It is sometimes convenient to set those cut thresholds automatically. 
That requires knowing that some triggers happen randomly, and thus should 
only by chance be associated with 'non-noise' data.  With the 
auto-pedestal setting, such noise data would be collected and analysed 
(mean and std.dev.), and then a threshold setting is calculated a few 
sigma above.  I think the name pedestal would refer to the mean value of 
the noise as such.

The analysis presumably happens once-in-a-while, and might also warn if 
the pedestals change more than some std.dev. fraction.

I hope Hans will fill in more details if needed (and tell if I'm 
completely off).

Cheers,
Håkan



On Tue, 23 Apr 2024, Weber, Guenter Dr. wrote:

> 
> Dear friends,
> 
> 
> I came across 'pedestal' in module V7nn (while trying to implement the
> missing 16 channel module 785N into NURDLIB). Is there an easy explanation
> what this is?
> 
> 
> 
> 
> Thank you very much!
> 
> 
> 
> 
> Best greetings
> 
> Günter
> 
> 
> 
>