Filtering White noise

[ChesterMiha]

Hello all,

I am in primary school and wanted to try something. I would like to generate white noise in Labview and the filter it with different types of FIR filters (high pass, low pass,...). Is this possible to make in Labview.

This is the first time I am using Labview, my physics teacher recomended it.

Thank ou for your help!

Chester

[Bob_Schor]

So the simple answer is "Yes, this is possible".  An informal definition of "noise" is "an unpredictable signal", which suggests that there is randomness in the signal.  LabVIEW includes, in its Numeric palette, a Random Number Generator that (to a good approximation) gives you a random number between 0 and 1, with all numbers (or, alternatively, all intervals, say 0 to 0.1, 0.1 to 0.2, 0.2 to 0.3, etc.) being equally likely.  This is called a "Uniform Distribution".

You could use this to generate a waveform.  But now you need to know something about "Signals", and "sampling", and "frequency".  All of these things are eminently doable.  There are filtering functions in LabVIEW that take waveforms in and return filtered waveforms out.  There are plotting routines that can show the "before" and "after" signals.  There are analysis routines that show the frequencies (sometimes called the "spectrum") of the signals in and out.

You'll learn a little LabVIEW, a lot of Signal Theory, and maybe even some fun math.  Plus there's a community here eager to help.

Bob Schor

[altenbach]

Filtering white noise is boring, because you'll end up with just less of it. More interesting would be to have a known interesting signal with noise added, then trying to recover the signal with less noise and minimal distortion. This will not only demonstrate the noise filtering, but also the filtering artifacts (shift, loss in detail, change in phase, amplitude, etc.).

[altenbach]

Also have a look at the filtering examples that ship with LabVIEW.