RMS vi error

[KQuigley]

Hi there

I am simulating a sine wave which is exponential decreasing. I then want to find the RMS and log of this wave. My problem is every now and then an error pops up relating to the RMS vi that I am using. The following is what pops up

" Error -20308 occurred at "ma_ptmFetch.vi" when called from "Cycle Average and RMS 1 chan.vi"
Possible reason(s):
Analysis: The waveform did not cross the mid reference level enough times to perform this measurement. . Check the signal length, reference levels, and ref level units."

I am guessing the reason is that the sine wave is decreasing too much and the values are too small for the calculation of the RMS. The thing is I need to have it decaying fast for my project! Anybody have any ideas??

Thanks
Karen

[johnsold]

Karen,

The Cycle Average and RMS.vi apparently needs a "cycle" to do an analysis. One of the inputs is cycle number.

I changed to the AC & DC Estimator.vi. It produces very similar results for the first few iterations of the inner loop but does not fail when the signal becomes smaller than the noise.

Run the attached VI with the RMS Select in each state and compare results.

Lynn

[KQuigley]

Thanks a million that works fine..