Problem autocorrelating a signal

[CJKS]

Hello All,

I've looked at the help file for the AutoCorrelation VI and replicated the block diagram shown in the example. I've also replicated the results by using a Simulate Signal Express VI instead of the Uniform White Noise VI (please see file attached). What I cannot seem to do is autocorrelate a real signal (frequency of TTL pulses from a PMT- which ought to be periodic white noise) via a PCI 6602 and BNC 2121. I've essentially wired a DAQ Assistant Express VI to the AutoCorrelation VI inside a while loop (file attached to next post). From the results I'm getting it looks like the program is just treating each new data point as a new autocorrelation instead of doing the sum over all points.

Any advice or observations would be most appreciated.

Cheers,

CJKS

[CJKS]

...and here is the attempt at autocorrelating a real signal...

[Ankita]

Hi,

I dont know if you have noticed that you have a graph indicator for outputting the autocorrelated signal in the first VI you posted. In the second VI however, you are outputting the autocorrelated  signal in a chart.

Could that be leading you to believe that the autocorrelation function does not work for real signals?

Ankita

[CJKS]

Dear Ankita,

Thanks very much for the response. It turns out that using the Pt. by Pt Autocorrelation VI instead of the regular Autocorrelation VI was the first problem. While that seemed to work the results were being displayed every 200 pts. Changing it from chart to graph fixed that. Thanks very much!

Cheers,

CJKS