Noise simulation done by SPICE

[svarun]

Hi all,

I have a question on noise simulation in analog circuits. Suppose I am doing the frequency domain analysis of an amplifier at a frequency 'f' with thermal noise coming in from the resistors. I want to see how much noise voltage is present at the output.

How is the noise be modelled in SPICE ? Does it choose the noise voltages from a random variable generator ?

Any help on this will be greatly appreciated.

Thanks
svarun

 

[m.salehi]

hi
do reed hspice documents?
they are usful for u.
The noise calculations in Star-Hspice are based on the complex AC nodal
voltages, which in turn are based on the DC operating point. Noise models are
described for each device type in the appropriate chapter in Volume II. A noise
source is not assumed to be statistically correlated to the other noise sources in
the circuit; each noise source is calculated independently. The total output noise
voltage is the RMS sum of the individual noise contributions:
regards.

2001.4_hspice.pdf