Re: FFT test with few kbits

From: Cristiano (cristiano.pi_at_NSquipo.it)
Date: 02/16/04 

Date: Mon, 16 Feb 2004 19:52:07 GMT

Ernst Lippe wrote:
>
> It would be much better to develop a single statistic that
> uses all Fourier components, e.g. the largest absolute value.

When you said that in another post, I tried some experiment, but I got
nothing. Could you elaborate a bit?

> I don't see any good reasons to discard the first Fourier component,
> after appropriate scaling it has the same behaviour as the others.

Please, could you show an example of "appropriate scaling"?

> It would be more symmetric to use the phase
> and the absolute value of the complex value (although in a very
> strict sense these are also not completely independent.

As I said, the phase is always uniformly distributed, so I guess it can't
show a thing.

The absolute values are used by NIST, but the statistic they use is empiric
and good only around 1e6 bits.
I seen that the absolute values seem chi-square distributed but I'm not able
to fit the distribution.

Cristiano

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