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

Ken Kundert wrote on Apr 29^th, 2007, 4:35pm:


Hi Ken:
    AFAIK, what HSPICE does is computing the total output noise and then dividing  it by the transfer function. so I may guess the computed input referred noise voltage/current will only be different by a factor of input impedance.

Julian.