noise analysis in Hspice

[Julian18]

Hi, there
About Noise analysis in Hspice,
the syntax is
.Noise vnod srcname inter
now from the syntax, it seems that we must give .NOISE a source, but what if i just want to see the noise at output node due to,say,the channel noise of a MOS, or the noise of some resistors, while igoring all other noise sourses. how should i do

BTB, what is the purpose of specifying a source to the .NOISE?to get the input refered noise? then since from textbooks(Tom Lee's book ), there are two input referred noise sources--input referred noise voltage& I/R noise current, how to tell which one it is?(since .NOISE just divides the output noise by the transfer function )
i really screwed up . Can anyone help out there?

thanks.

Julian

Added after 2 hours 32 minutes:

anybody wanna shed some light on this?

 

[Blackuni]

Hi Julian,

If i understood correctly..You can try .LIN noisecalc=1 along with .ac analysis.

For this port element has to be defined which can act as a noiseless impedance or as
a voltage source in series with the port impedance.


Hope this helps.

Thanks