How do you count the frequency of a boolean signal?

[aeastet]

Here is a simple example of waht I did. If you change the loop time the cal freq vi does not care.

[herrlin]

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aeastet wrote:
Here is a simple example of waht I did. If you change the loop time the cal freq vi does not care.

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Im not following you becasue if you change the loop time the freq changes.

[aeastet]

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Will15648
wrote:

.... I need a live readout of the frequency of this signal.

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Herrlin wrote:

I still would like to see how Will is getting his data from
the digitial IO.  In my mind for this code to kinda work the data would
have to be streaming real time.

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Based on the first request on this tread it got the impression that it was a live measurement.

[aeastet]

But we are not going off of the loop frequency we are going off of the boolean change. The chage is just hard coded to show the example of what I am talking about.

[herrlin]

All I’m saying is without knowing the device sampling rate you can’t accurately figure out the frequency.  I feel that it is poor practice to use system time to determine sampling rate.  As far as the LIVE frequency goes that’s the frequency out that is live not the input.

[aeastet]

That is why I asked earlier how accurate the measurement needed to be.

[Ray.R]

After reading the initial post, here is a test bed example:

 

The top While Loop represents the randomly generated boolean signal at a frequency between 4 and 26 Hz.  The signal uses a Notifier which triggers the bottom While Loop.  The delta time is calculated on the difference in milliseconds.  That is why the delta time is divided by 1000 to convert to seconds.  Unless I am mistaken, frequency is f=1/T, where T is the period (or delta t in this case), not delta-t/60.  

The flashing LED's represent 1)  The random ON or OFF state of the binary signal (that was not specified, so I invented  for this example) and 2) an boolean that alternated between 0 & 1 at the rate of the varying frequency (for visula illustration).

 Sorry about my original post and hopefully, this example will help somewhat.  And yes, it's been one of those days..  😉

Message Edited by Ray.R on 03-11-2010 04:53 PM