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Topic: DFT vs DWT on raw data
Replies: 1   Last Post: May 2, 2013 6:02 PM

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Derek Goring

Posts: 3,919
Registered: 12/7/04
Re: DFT vs DWT on raw data
Posted: May 2, 2013 6:02 PM
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On Friday, May 3, 2013 8:17:09 AM UTC+12, Jurgens J J Cornelius wrote:
> Hi
>
> Hope somebody can help! I have an Xcel spreadsheet with time in milliseconds in the first column and rms voltage in the second recorded during disturbances. I would like to apply the DFT as well as the DWT on this data to compare the results and decide which tool to use for further data manipulation from time to freq. domain. Has anyone done this exercise and how would I go about setting out the data into the DFT?
>
>
>
> Thank you very much.


If the data are equispaced, you don't need the time, just the interval between them.
So, you read the data in using xlsread, extracting just the 2nd column.
Then:
help fft
to get the DFT, and:
help dwt
to get the DWT.

You should search this newsgroup to find out how to calculate the frequencies for the DFT and the timescales for the DWT.




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