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 2.GQ Geiger Muller Counter
 Comparison about data charting representation		  New Topic  Reply to Topic
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Damien68

France
780 Posts
Posted - 09/01/2019 :  01:23:48  Show Profile  Reply with Quote
I post this just for general information,
I compare 2 ways to plot a average curve :
- The first by convolution with a cardinal sinus, which constitutes a low pass filter (exactly a brick-wall filter).
- the second is a moving average (which is a convolution with a rectangle).

The first way requires a little more calculation but is still very fast (less than a second for 20,000 points with a Windows PC, .NET framwork, CPU: i5 6th generation) it gives a smoother curve and no less significant
The second is more speed but leave artifacts which are due to edge effects with the convolution window edge.

below the 2 solutions then an implementation of the LPF filter
see more information about sinus cardinal filter at: https://en.wikipedia.org/wiki/Sinc_filter

Filtered by a low-pass filter (LPF) with troncated sinus-cardinal window convolution:
Image Insert:

216998 bytes


Filtered by a rectangular window convolution (mobile average)
Image Insert:

226113 bytes

Exemple of sinus cardinal convolution implementation under Visual Basic .NET
Image Insert:

198974 bytes
Note: above, function sin (x) must be defined in radians

and his calling:
Image Insert:

34681 bytes
Mastery is acquired by studying, with it everything becomes simple
Edited by - Damien68 on 09/07/2019 23:47:51
Reply #1

EmfDev

2143 Posts
Posted - 09/03/2019 :  09:29:15  Show Profile  Reply with Quote
Thanks for sharing some great information! We could use some of those techniques to improve our computations! :D
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Reply #2

Damien68

France
780 Posts
Posted - 10/28/2019 :  05:45:37  Show Profile  Reply with Quote
under certain conditions the moving average may be a little more representative.
In fact, trapezoidal window convolution seems to be perfect.
Mastery is acquired by studying, with it everything becomes simple
Edited by - Damien68 on 10/29/2019 04:02:09
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Reply #3

EmfDev

2143 Posts
Posted - 10/29/2019 :  08:53:36  Show Profile  Reply with Quote
There might be a way to toggle between both.
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