derivate labVIEW FPGA

[jeanT]

hi everybody

i would like to derivate a signal, and my first idea was with a shift register ( see picture attached) and i would like to know if it could be enough or if it has to be improve.

thank you !

J.

[dan_u]

Technically yes, this should work. Except the data type, U16 will only allow positive values, but the derivative might also be negative.

But it really depends on your requirements and on the signal quality.

If the signal noise is bigger than the usual difference this simple derivative will not be very useful. You might have to filter it.

[jeanT]

Thank you very much dan_u for your quick answer ! i was wondering if it is better to divide by the periode (see picture attached), the signal has a frequency of 1Khz.

another question : when you say " you might to filter it" you mean with labview ?

thank you again !

J.

[dan_u · Accepted solution]

Of course, if you need the speed in units/s you have to divide by the period. Since divisions are quite heavy on the FPGA I would recommend multiplying by 1000 instead of dividing by 0.001 (if the sampling rate is constant).

Yes, if the signal is too noisy filtering the position signal or the speed signal in LabVIEW might be necessary. An example for a simple "filter" would be a moving average.

[jeanT]

Alright ! thank you very much for these advice