"bamse" <bamse@kyllingen.dkkkk> wrote in message news:<6BEnc.4$NS3.3@news.get2net.dk>...
> does additive white gaussian noise only change the amplitude of a signal or
> does it change both amplitude and phase?

There are two ways of looking at Gaussian noise:

Time domain: Random numbers are drawn from a Gaussian distribution
and added to the samples in the signal, thus "changing the amplitude"
of the individual samples.

Frequency domain: A signal with specified frequency magnitude, given 
by the noise autocorrelation function, and random phase response is 
added to the signal spectrum, thus "changing the phase" of the spectrum.

Rune

does additive white gaussian noise only change the amplitude of a signal or
does it change both amplitude and phase?