spectre rf中的问题

liufdz

想请教下，为什么做psp、pac等前先做pss，另外psp和sp、pac和ac有什么区别

longma

PSS/QPSS are large signal analysis to define the periodic steady state. PXX/QPXX are small signal analysis based on the steady state calcuated by PSS/QPSS. This is similar to the relationship between DC and AC/SP/Noise.

liufdz

Thanks longma, i can understand the relationship between DC and AC/SP/Noise,can you explain the function of pss.I just think it as harm harmonic balance ,what is the diffrence between HB and pss.
        Good luck to you!

longma

PSS analysis is used to determine the periodic operating
point for the circuit. The periodic operating point can then be used during
a periodic time-varying small-signal analysis, such as PAC, PXF,
PNOISE, PSP, or PSTB.

TO run PSS, SpectreRF has two engines: shooting or harmonic balance.


Generally, harmonic balance (HB) is very efficient in simulating weakly
nonlinear circuits while shooting is more suitable for highly nonlinear
circuits with sharply rising and falling signals. HB is more efficient than
shooting in handling frequency dependent components, such as delay,
transmission line, and S-parameter data.

faithfully

I'm aware about the relationship between PSS and PXX as you explained, but why we should do PSS first and then PXX, while for AC we do't need to do DC first as well?
And, why during the normal PSS/QPSS analysis, we do't need to choose shooting or Flexible Balance Engine, only when we want to caculate IIP3 by QPSS, then we choose one?

fengsui

because the PSS can find the dynamic operation point, and then based this changing "DC" operation point you can do PAC, PSP etc., but for AC simulation, the operation point is constant.

longma

No, if you are using the version having HB/shooting option, you have to choose one for both PSS or QPSS or envlp. The default is shooting.

原帖由 faithfully 于 2007-7-19 10:21 发表
I'm aware about the relationship between PSS and PXX as you explained, but why we should do PSS first and then PXX, while for AC we do't need to do DC first as well?
And, why during the normal P ...

[ 本帖最后由 longma 于 2007-7-19 14:58 编辑 ]

liuyang1986

多谢楼主

romberg

But I'm still not aware of the difference between the steady state of a circuit and the periodic steady state of a circuit .

shykongxin

thanks!