I understand your situation.

In your case, QPSS is also not suitable.

You should use Envelope Analysis with fudamental frequency of 1/(20*Tclk).

Envelope Analysis of Agilent ADSsim and GoldenGate support small signal noise analysis.

I recommend you to use RFDE2008U2 or GoldenGate-4.3.0. GoldenGate-4.3.0 is more recommended since convergence is very robust.

But GoldenGate-4.3.0 might not be suitable for your purpose.

So you might have to use RFDE2008U2 not GoldenGate-4.3.0 since we can't evaluate Time_Averaged_Noise_Power_Density(freq).

http://eesof.tm.agilent.com/products/goldengate_main.html#whats_newBy using these simulators, you can observe small signal noise Noise_Power_Density or Noise_Power around any harmonics you specify.

RFDE2008U2 calculates

Time_Averaged_Noise_Power_Density(freq).

GoldenGate-4.3.0 calculates

Ensemble_Averaged_Noise_Power(time).

So you can observe time behavior of small signal Noise_Power by using GoldenGate-4.3.0.

This is a little similar to Pnoise/TDnoise Analysis of Cadence Spectre where Ensemble_Averaged_Noise_Power_Density(time,freq) is evaluated.

About monte carlo type noise analysis similar to transient noise analysis, it is also available in Envelope Analysis of RFDE2008U2.

But it is not available in Envelope Analysis of GoldenGate-4.3.0.

Although you can evaluate small signal transfer function by using Envelope Analysis of RFDE2008U2, you can not evaluate it by using Envelope Analysis of GoldenGate-4.3.0.

Envelope Analysis of GoldenGate-4.3.0 doesn't support small signal analysis although it supports small signal noise analysis.

But you might be able to evaluate a transfer function by using two tones Envelope Analysis of GoldenGate-4.3.0 where one is N*1/(20*Tclk), the other is small input signal tone.

I don't know whether Envelope Analysis of Cadence Spectre supports small signal noise analysis although it can calculate AC charactersitics at specific envelope time.

http://www.cadence.com/Community/blogs/rf/archive/2009/01/14/tip-of-the-week-mms...