First of all, thanks for your comments.

I found a solution but I can only do a spectrum analysis of a signal which isn't phaseshifted or have one period.

> A := MapleSim:-LinkModel(): > n := 50;

> with(DiscreteTransforms);

> with(LinearAlgebra);

> with(Statistics);

> simData := A:-Simulate(output = datapoint);

 > zeit := simData[1 .. -1, 1];

> wert := simData[1 .. -1, 2];

> X2, Y2 := FourierTransform(zeit, wert);

> N := RowDimension(simData);

> listplot([seq(X2[f], f = 1 .. n)], gridlines = true);

 > a_0 := Mean(wert);

> spec := [[0, a_0], seq([evalf(i), X2[i+1]], i = 1 .. n)];

> plot(spec);

> dspec := [[[0, 0], [0, a_0]], seq([[evalf(i), 0], [evalf(i), sqrt(4/N)*X2[i+1]]], i = 1 .. n)];

> plot({seq(dspec[i], i = 1 .. n+1)}, axes = boxed, color = blue);

So I need help to do an independent spectrum analysis of a signal. I heard that it is also possible to do this by the MonteCarlo attachment, but that doesn't work very well.

Is there any solution to do a spectrum analysis like in this program?

Thanks for help

Johannes