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FFT units

FFT units

I'm trying to find the units when using icfft(). All the examples plot the results vs data points and not time.

Specifically, I am try to convert S11 data into time domain to see where reflections occur.
4 REPLIES 4

FFT units

Like a lot of MathCad functions, FFT's and inverse FFT's don't handle units well. You can work around this by defining functions that put units back in:

fxt(v) = fft(v)*(unit of choice)

Set up this function, put in a problem you know the answer to, and check the results. Not elegant; but it will work.


Fred Kohlhepp
fkohlhepp@sikorsky.com

FFT units

The problem is, I don't know what the units should be. I know the frequency data points that are input into the IFFT(). I don't know the conversion to the time scale and MAthCad does not provide examples that convert the units. They just plot vs. data points.

FFT units

Okay, try this!
Fred Kohlhepp
fkohlhepp@sikorsky.com

FFT units

On 10/19/00 9:26:10 AM, Anonymous wrote:
>Okay, try this!
>Fred Kohlhepp
>fkohlhepp@sikorsky.com

Here is an enhanced version of your mathcad file. There is an error in yours. Look at frequency of the peaks in your fft, and you will see they are slightly off.


John Sellers