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 Fourier transform - change parameters		  New Topic  Reply to Topic
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vlnew

United Kingdom
35 Posts
Posted - 04/18/2022 :  09:37:13 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Hello,

I am doing Fourier transform of a very regular and smooth sinus-like function. As a result I expect a very smooth Fourier transform with easily detectable frequency maxima. But am getting an output which is calculated with large "time steps" on the X axis. How to decrease these steps?

Thanks!

Sam Fang

293 Posts
Posted - 04/20/2022 :  04:05:14 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi vlnew,

Frequency resolution in FFT was determined by:
df=1/(N*dt)

To decrease df, you can increase number of input data N or sampling interval dt.

If your input data can't be changed, you can also try Origin's Zoom FFT app.
https://www.originlab.com/fileExchange/details.aspx?mode=sandbox&fid=878

This app requires Origin2022 temporarily.

Thanks.

Sam
OriginLab Technical Services
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