# LabVIEW

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## Changing peak of sine wave in some time interval

Hi,

I got one sine wave signal. With Peak detection I can get its peak and after bundling it together with locations , I can get a XY graph which shows the peaks vs time. However, everything 10s, the peak is gonna change. I would like to show the continous change of peaks in this graph. However, even though I extended the X(time) axis, the peak can not change after some specific point. What I got is the peak line jumps to a higher or lower level. However, no continous change is shown.

Is it because of the size of the data array? I mean, the graph refreshed every time after it got N numbers of data? Should I increase the number of N through addings buffers or change N somewhere?

Thanks.

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## Re: Changing peak of sine wave in some time interval

I'm not clear what you are trying to accomplish. Can you explain a bit more about your application and perhaps post a bit of your code showing the problem?

Mike...

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Certified LabVIEW Architect
LabVIEW Champion

"... after all, He's not a tame lion..."

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## Re: Changing peak of sine wave in some time interval

Hi,

I got a sine signal through DAQ with f=11KHZ and its peak is changing. I would like to have one graph tracking the peak change in some time interval. Let us say 90 seconds. What I found is that the graph is keep refreshing after some very shor time instead of keeping track of change of peak.

Here is the code. Thank you.

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## Re: Changing peak of sine wave in some time interval

Any idea? thanks.
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Solution
Accepted by topic author oly

## Re: Changing peak of sine wave in some time interval

I have noticed a couple things: First, all you displays are graphs and graphs don't have any memory associated with them each time they update the old contents are completely replaced by the new contents. From the way you describe what you want, you need a chart somewhere to capture the peak value in every acquisition.

Second, you don't have a sample count wired to the acquisition VI. Run in this way the read function reads however many points are available - and sometimes that count is zero. Try wiring a constant with 100 in it to the number of samples input.

Mike...

Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion

"... after all, He's not a tame lion..."

For help with grief and grieving.
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