Geoffrey Coram

onoise_spectrum in ngspice is reported in V^2/Hz. The onoise_spectrum is computed as the PSD of the noise source times the magnitude-squared of the transfer function (H times its complex conjugate)....

I was unaware of sqrnoise; I see that topolarity did set that option.

> If we have a factor of 2 what is the same as two contributions to same branch we can assume > it is a parallel circuit of two uncorrelated...

I have now checked two commercial simulators using ` I(b, a)

To clarify my previous post: when ns1=ns2=1, the noise for R=1 at T=27 C is ~ 1.66e-20 V^2/Hz For ns1=1, ns2=2, the noise is 3.32e-20 V^2/Hz, which is twice the...

@tcaduser is correct; the noise sources are uncorrelated. And @topolarity is also correct; having the two noise sources is equivalent to having sqrt(2) in front of a single noise source....