I'm following the

Nyquist FFT Tutorial. But I'm getting a slightly different result than expected. The output from `(fft-test)` should have -1 in the 9th array element, but I'm getting -16:

> (fft-test)

fft-test : (SEND FFT-ITER :NEXT) = #(3.28013e-15 2.79029e-15 1.15578e-15 2.79029e 15 2.79029e-15 2.79029e-15 6.73636e-15 1.68587e-07 -16 2.79029e-15 -6.73636e-15 2.79029e-15 -2.79029e-15 2.79029e-15 -1.15578e-15 3.28013e-15 -0 2.79029e-15 1.15578e-15 2.79029e-15 2.79029e-15 2.79029e-15 6.73636e-15 -1.68587e-07 3.4366e-07 2.79029e-15 -6.73636e-15 2.79029e-15 -2.79029e-15 2.79029e-15 -1.15578e-15 3.28013e-15)

I copied and pasted the code from the tutorial, so I doubt there's a mistake on my part. Is -16 the correct result?

Also, the tutorial describes the FFT array as:

- the DC component goes in array element 0

- the Cosine part is in elements 2i - 1

- the Sine part is in elements 2i

- the Nyquist frequency component is in the last element

I'm not clear what the meaning of "cosine part" and "sine part" are. The array as shown above doesn't seem like it could be the coefficients for SUM(Asin(2πnt) + Bcos(2πnt)) where n is the frequency. Can anyone please clarify this for me?

Thanks for your assistance!