From: Stefan Jahn <stefan@gr...> - 2006-05-12 07:51:16
Am Do, 11.05.2006, 18:55, schrieb Manley Head:
> Hello Stefan;
> I don't know if my thinking is wrong(quite possible) or if there is a
> problem with the Qucs noise handling.
> I am trying to measure the phase changes in a simple circuit (attached)
> driven by a noise source.
> I find that the output contains a (noise) voltage that is not a complex
> number as it is when driven by a ac voltage source.
> Since it is a real number only then there is no phase information.
> This remains the case even when passed through a reactive circuit.
> Why is the noise voltage not a complex number? Is this not a problem
> or is my thinking messed up?
Hm. As far as I know it is impossible to assign a phase information to
a random signal like noise. I think it was hard enough for engineers and
mathematicians to assign an amplitude in a certain bandwidth (using some
tricks about probability).
Michael: Am I wrong?