raja.cedt wrote on Oct 25th, 2011, 1:38pm:hello Garrett.Neaves,
To be frank i didn't understand your answer, may be i am not that good in this basics.
if s=gm/CGD +j0, then there is no complex frequency, only you have attenuation, so up to my knoledge there is sinusoidal signa which can make Vout zero....
Could you please explain clearly...
Thanks,
raj.
Hi Raj,
s=gm/CGD +j0 is a point in the complex frequency plane. Vout(s)=0 at this frequency in the complex frequency plane.
A circuit excited by pure sinusoids such as when sweeping the frequency in an ac simulation, is represented in the complex frequency plane as a sweep along the jw axis.
The value of Vout(jw)/Vin(jw) as w is swept is determined by the poles and zeros of Vout(s)/Vin(s) wherever the poles and zeros lie in the complex frequency plane.
That is, the poles and zeros of Vout(s)/Vin(s) effect the shape of Vout(jw)/Vin(jw) versus w even when the poles and zeros do not lie on the jw axis.
I explained it as clearly as I am able in this posting type of communication. Maybe someone else can explain in a way which would be more helpful to you.
Best Regards,
Garrett