Ripples

[Mudda]

Hi,

I am measuring a current drawn by a DC motor. I see ripples in the data which are comming from the commutator. I would like to measure number of ripples in the signal so that I can measure the speed of the motor. What would be the best way to do that. I could use a threshold and see how many times the signal is crossing it but the whole signal is moving depending on the load of the motor. So I cannot use a fixed threshold and also at the same time I cannot predict which way the signal is going to shift. I was wondering whether there are any VI's for this kind of measurement in any toolkit.

Thanks,

Mudda.

[PaulG.]

There are quite a few VI's under the signal processing>waveform measurements palettes that would work for you. I would look at tonal measurements first.

[Mudda]

Thanks paul