Quote:I_Source:SRC2 0 _net179 Type="ItSine" \
I[1]=if (_tr_state == 0) then 100 uA*exp(j*2*pi*(0/360-0 nsec*400 kHz-.25)-(time-0 nsec)*0)*step((time-0 nsec)+tinyreal) \
else 0 endif \
Freq[1]=400 kHz Idc=0 mA \
I_Tran=if (_tr_state == 1) then damped_sin(time,0,100 uA,400 kHz,max(0,0 nsec),0,0) \
else 100 uA*step((0 nsec-time)-tinyreal)*sin(pi*0/180) endif
Why do you use ItSine as SRC2 ?
Basically this is a time domain signal source although it seems to be valid even for HB as I see the above I_Source description.
What effect do you expect in your simulation ?
Do you expect transient assisted HB, where HB convergence is helped by time domain SRC2 drive ?
Do you understand HB analysis, HB with small Signal Analysis, pure small signal analysis, envelope analysis, etc. ?
Quote:I tried with ADS HB simulation, but if you add a small injection current at 400KHz to the VCO running at 4GHz. HB simulation ingored the injected current as its frequency is not close enough to VCO harmonics.
The reason is you do only 1 tone HB ana while 2 large signals exist.
Quote:Then I set freq1 in the HB to be 400KHz, I need to set the HB order very high and it really can not converge.
You have to use 2 tone HB ana. 400kHz must be set as Freq[2]. Freq[1] is autonomous large signal.
There are three possibilities for simulations of VCO purturbed by some signal, although (1) is actually not purturbation, that is, not pulling.
(1) 1 tone HB base Noise Analysis, One autonoumous signal(2GHz) + small signal noise source having specific PSD.
In this case, you have to use I_Noise as SRC2.
(2) 2 tone HB base Noise Analysis, One autonoumous signal(2GHz) + One fixed signal(400kHz)
In this case, you have to use I_1tone as SRC2.
(3) 2 tone Envelope base Noise Analysis, One autonoumous signal(2GHz) + One fixed signal(400kHz)
In this case, you can use any complex envelope signal centered at 400kHz as SRC2.
About (1), you can also do by using PSS(Shooting or HB) of SpectreRF.
I confirmed Cadence HB-QPSS(MMSIM 6.2) doesn't support autonomous QPSS yet.
So Cadence MMSIM 6.2 can't do (2).
About (3), I don't know whether SpectreRF(MMSIM6.2) can do.
Except for (3), you can do with only using Cadence analoglib in Agilent RFDE.
About (3), there are some limits if you don't use adsLib in Agilent RFDE.
What simulation you should use is depend on what effect you want to evaluate.
I guess you want to do (2).
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simulation of VCO pulling caused spur (Read 12507 times)