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simple FFT

Tue, 08/31/2010 - 09:06 am

Dear all,

this is an easy one for you.
I have a long voltage(y)-time(x) trace, sampled at high resolution (20 kHz). that means many points.
i would like to do a simple spectral analysis of my signal, but the fft gives me a meaningless output. i do not know either how to obtain the right units. any suggestions?

thanks, P

Igor

Hello P.

The length of your data set is rarely a problem when it comes to the result or interpretation of spectral analysis.

If you have a problem obtaining the correct units you need to make sure that your input units are correct, i.e., if your data is scaled in units of time the transform is scaled in units of Hz.

I would also suggest that you consider using DSPPeriodogram which has built-in features (esp. /SEGN) that are designed to break your data into multiple segments and average out the results.

A.G.
WaveMetrics, Inc.

August 31, 2010 at 09:49 am - Permalink