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Suppose you have 1,000 numbers chosen at random with a uniform
distribution [-1, +1]. Now suppose you take the discrete Fourier
transform of this sequence of numbers. Since the input is random, the
output is also random. But what distribution does it follow?
I've searched all over the Internet, and I can't seem to find the answer
to this trivial question.
My best guess is that the Central Limit Theorem would apply, resulting
in both the sine and cosine coefficients being normally distributed.
(But with what parameters?) The CLT definitely applies to independent
/identically distributed/ random variables. I'm fuzzy about what happens
when the variables are not identically distributed, however. In this
case, each variable follows a uniform distribution with the same
midpoint, but the width of the distribution varies for each variable.
My simulation results seem to indicate a normal distribution also. But
that doesn't really mean anything; there could just be a bug in my
program which causes it to spit out dud data. Or perhaps the
distribution /looks/ normal but is actually subtly different.
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