This means that the positive and negative real parts will be identical, and that the positive and negative imaginary parts will be the same, but of opposite sign. Remember that for real-valued inputs, the transformed data is Hermite symmetric. If you need to work with non power of 2 sizes, you should pad the ends of the data (usually with zeroes.) Thus, you can form the Fourier transform of a set of 128 numbers, but not a set of 100 numbers. However, the computer implementation requires that the size of the set be a power of 2. The Fourier transform converts a set of numbers into another equal sized set of numbers. You will enter the input numbers into the input range and select a place to put the outputs, and you will select either forward (default) or inverse transform. Clicking OK brings up the dialog box to control this. Select the 'Fourier Analysis' function from that list.
If you then select: 'Tools->Data Analysis.' you will get a little list of functions. This adds a ' Data Analysis.' item to the Tools menu. From the Tools menu, select " Add-Ins." then check the Analysis Toolpack and click 'OK' To use the Fourier functions, you must first enable the Analysis ToolPack. If you intend to use Excel for this purpose, I encourage you to look through their help files to understand it, but here are a few notes. While these notes are somewhat specific to Excel, much of the content pertains to other computer-based Fourier tools.įortunately, Excel has some built in functions that make it possible to perform Fourier transforms relatively easily.
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