Noise filtering

[Xiao@Gemini]

Hello everyone, I'm using Campbell scientific multiplexer to multiplex 8 sensors into 8 channels of NI 9221. The raw data is individual pulses, only two were connected as you can see in the following figures. I'm using amplitude and levels VI to acquire the lower state level of each pulses, and wire to a ptbypt median filter which I'm hoping the noise can be filtered out. However, it does not works as I expected. Is there any other method which can stabilize the signal? Thank you in advance. 

 

[eorivia]

Hello Xiao,

I tried to replicate the behavior of your example and I got the following result after using the point by point median filter:

Just in case, I used a 1 Hz, 10% duty cycle and -9V square signal as a software input. After reviewing your code, the only difference that I found was this:

Try removing that build array VI to check if the result improves. I will attach the code that I used for you to use it as a reference.

Regards

[Xiao@Gemini]

For each pulse, it's pretty clear as you can see from Fig 1, what I want to plot is the pulse amplitude, that one has noise as you can see from Fig 2. 

[jesicadiaz]

Hi Xiao, 

Have you tried to use other LabVIEW filtering functions (e.g. Butterworth filter, )? If so, have they worked? 

Regards,