Boolean pulse generation

[m-s]

Hello,

I am using the FFTSpectrum (Mag-Phase) VI to calculate the averaged FFT spectrum of a time domain signal from an instrument. This averaging has to be done for each value of a parameter that is being varied in a loop. So, I want to send a true pulse to the restart averaging pin of the VI just before I start the averaging but if I just feed in a constant true signal, the VI will keep resetting. How do I generate a conditional boolean pulse (as small in width as possible) ?

Thanks.

[mfitzsimons]

The size of the pulse will make no difference.  If it is a loop connect the loop count to an =0 comparison for make a True pulse at the start of the loop.  If it is not in a loop then not sure what you should do.  Post code if this doen't solve your issue.

[m-s]

Hi

Thanks for the response. Yes, it is a loop and I have the setup for a comparison in there. But going back to the original question, how do I generate the pulse ?

I cannot assert a constant true signal as that would keep resetting the averaging unless the comparison VI has an error out pin that can help sync the end of the pulse with the start of the FFT VI (?). I am new to Labview, hence I could be missing something.

Thanks.

[mfitzsimons]

Reset averaging is uses if you wanted to average multiple sample.  Some VIs have memory that retain previous run information so initialize clears the previous sampled memory.   If you have just one data set then reset it each time it is called.  The pulse is not your solution.

[IanW]

You could use a shift register and some logic to latch on to your comparison. Take a look at the attached code, I hope it will give you some ideas.

Ian