[PhilBot]

Originally Posted by Felipe Sagui

I have a problem with the integration in labview...

when I integrate a sine curve I get a -cosine but with differents amplitudes...the pictures attacheds are showing the front panel and block diagram.

is it correct? If not....any idea to fix it?

thanks

This looks reasonable.

Notice that the First Integration is always positive. This makes sense since the sum starts out at zero, and after one full cycle, the sum of all the sine values will be zero again. So the first integral is offset up by half its peak/peak value.

Since the First integral is always positive, the Second integral won't look anything like a sine wave, it will always get bigger.

I wonder if you look up the actual formulae for first integral of a sine this is what you'll get (hint hint). I'm surprized that this wasn't the first thing you did (rather than just posting on CD).

I would also think that the resulting magnitudes are a function of frequency, so may need to think about your sample times.