What is the difference between butterWorth filtration in Measurement Studio and butterWorth filtration Labview

[Lew]

Hello.  I am not sure I am addressing my question at the good person, but I have to begin somewhere....

We analyse losts of data from saved files.  Some are treated with labview, other with Measurement Studio.  We compared the results from labview and MS butterWorth filtrations and it is almost the same exept at the beginning and the end of the signal, where MS seems to react badly compare to Labview. I always tought that both routines had the same calculation process and will give the same answers, but it is not.  The difference is not "that" big, but it gets bigger if we do more than one butterworth filtration.

So what is the difference between them?

[JonathanN]

Hi Lew,

Could you perhaps be a little more specific on the differences you are seeing (Perhaps post some screenshots or example code). Do you see this behavior with a certain type of butterworth filter or all of them? The algorthims should be the implemented in the same manner. If you could build a small example that shows otherwise, that would great.

Best Regards,

[Lew]

Well, I am sorry, it seems that the error was mine.  The inputs I gave to both program was different by only two point.  The array was "shifted" by one point in one of the program (you know, the "array index 0 " problem...).

Hope I did not create too much troubles

Thanks again. 

[JonathanN]

Hi Lew,

Small things like that always seem to get me.  Good luck with future applications.

Best Regards,