I'm trying to implement a Fast Fourier Transform (Radix-2) in MS's Excel VBA. The code I'm using pulls data from a range in the worksheet, does the calculations, then dumps the results in the adjacent columns. What I'm having trouble with is 1) know what to do with the resulting X[k] arrays, and 2) matching these results with the results from Excel's built in FFT (they do not currently match). The code is shown below. Thanks in advance for your help. I'm trying to implement a Fast Fourier Transfor