analog_chip
Full Member level 1
- Joined
- Oct 9, 2011
- Messages
- 99
- Helped
- 1
- Reputation
- 2
- Reaction score
- 1
- Trophy points
- 1,288
- Activity points
- 1,994
Hi,
I am simulating a circuit with nonlinearity, time variance & frequency translation. The output Vout=(V1) + (V2) .
I used pnoise+noise separation to find transfer function from drain noise of M1 to V1, V2 and Vout i.e. TF1, TF2 and TF and I find that TF=TF1 - TF2 which I want because it cancels M1 noise.
But when I model drain noise of M1 with a current source as shown in figure, and perform pac analysis, I do not see cancellation and I find TF=TF1+TF2
I also modelled it with small sinusoidal current and did transient, performed FFT and found TF=TF1+TF2
I am doubtful which one to trust. Can pac and transient do the job of pnoise OR it is a mistake?
<a title="NTF.jpg" href="http://obrazki.elektroda.pl/9266728800_1409197311.jpg"><img src="http://obrazki.elektroda.pl/9266728800_1409197311_thumb.jpg" alt="NTF.jpg" /></a>
- - - Updated - - -
I am simulating a circuit with nonlinearity, time variance & frequency translation. The output Vout=(V1) + (V2) .
I used pnoise+noise separation to find transfer function from drain noise of M1 to V1, V2 and Vout i.e. TF1, TF2 and TF and I find that TF=TF1 - TF2 which I want because it cancels M1 noise.
But when I model drain noise of M1 with a current source as shown in figure, and perform pac analysis, I do not see cancellation and I find TF=TF1+TF2
I also modelled it with small sinusoidal current and did transient, performed FFT and found TF=TF1+TF2
I am doubtful which one to trust. Can pac and transient do the job of pnoise OR it is a mistake?
<a title="NTF.jpg" href="http://obrazki.elektroda.pl/9266728800_1409197311.jpg"><img src="http://obrazki.elektroda.pl/9266728800_1409197311_thumb.jpg" alt="NTF.jpg" /></a>
- - - Updated - - -