Align up real signal with filtered one

[Bojer]

I have this signal where there is some noise in, I have then added a "Add waveform processing" and inserted a Bessel filter.

when I then read up the signal from the digitizer, then I read both the unfiltered and filtered waveform.

Original is readen with "Multi Fetch WDT" and filtered with "Fetch Array Measurement".. the problem is that the signal are not aligned, some data is missing in the filtered version.. I have tried a lot of different things to align them up.. but every trial has failed.

I have sent a picture of what I mean 🙂

BR Bojer

[Nathan-P]

What you are seeing is expected.  The software filters are implemented as FIR filters, so the beginning and end of the data is removed or windowed.  If you want to line up the rising edge with the original data, the method I would use is as follows:

1. Select a voltage value on the rising edge, like 60,0

2. Search each waveform for this value

3. Pad extra data at the beginning of the filtered waveform such that the 60,0V index between both waveform matches.

Enjoy,

Nathan