How exponential filter or smoothing filter Works?

[shami81]

Hi there,

I am ehtisham and i am using PCI-4472 DSA card. I am using express filter VI and i want to use the exponential filter. Can some one please explain what this filter exactly do when i use it. i m posting a picture also so that you guys can easily understand it. Moreover please guide me how to use this filter using C#.NET as i have found a very good example which is related to my work i can use it with a little modification but i need to implement filters in that example. Can anyone help me about this i need the code to implement the smoothing exponential filter.

Hoping for your quick response.

[Kevin_S]

Hi shami81,

You can see the code that implements the Express Filter VI.  After you select OK in the setup dialog, right-click on the express VI and select Open Front Panel.  You can now open the block diagram of the filter implementation.

Regards,
Kevin S.
Applications Engineer
National Instruments

[ATE_Dude_22]

What are the differences in how LabVIEW implements smoothing filter for "rectangular", and "triangular" for the moving average? Are they both sliding windows, or??

I have a dataset that the moving average (set to 5), actually changes the first few datapoints in the array, and causes the waveform to fail monotonicity when set to "triangular", but not when set to "rectangular"? I would like to know how these moving averages are applied by the Configure Filter" vi available on the waveform conditioning palette.

[K_Joy]

Hi ATE_Dude_22,

If you drill down into the built-in VIs, you can find the difference in the implementation. After you configure the Filter Express VI, you can right-click on it and select “Open Front Panel,” then follow the filter type input. Smoothing is filter type index 4. Eventually, you will see that the only difference between rectangular and triangular is how it calculates the coefficients. Everything else is identical between triangular and rectangular.

 

Regards,

Kelsey Johnson

Applications Engineer

National Instruments

[ATE_Dude_22]

Ty Kelsey.