Hello we want to get the frequency from a analog Input (puls) with labview 6.0x. How can we handle the Data?

[Andy H]

I get the Data with the example Aquire N- Scans Analog Hardware. So I get the Data
Now i want to get the Frequency from this Data array
Does somebody has a solution for this or example?

Think have to select the data to High or low, then
I can calculate the frequency.
The problem is how can I do that

[Jeremy Braden]

Consider using the FFT VIs (fast fourier transform). They find the component frequencies of the incomming data. Look in the shipping examples.

If you do not have the VI, you can use something like taking the difference between every adjacent points to get information about the first derivative of the data. (It is not the first derivative because you have not divided by dt). You can then see if the slope changes sign, ie crosses zero. This means the data had a peak or valley. (you will need to check the second derivative to make sure you are not at an inflexion point). Count the number of sign changes and divide by 2 to get the number of peaks. You can then divide this number by the elapsed time for recording the data to get the frequency of the
data.

I attached a rough example to demonstrate. It needs more refined error checking like inflexion checking.

[Andy H]

Thanks good Idea
Now I got the graph with the Main Peak Information
How do I change the graph into just a value?

(I can´t open your example in LV6.0 could you send it again ?)