The pictures just show some Chinese writing (I assume it'sChinese) and "pp.sohu.com". It is possible to add pictures as attachments (one per post) on the Options tab when posting a reply.
So without more detail, it's hard to know what the problem is.
Figure 1 is as below.
Figure 2 is as below.
Because the Q is so high, the lack of timesteps in a default simulation means that it will not be able to properly see the effect of the resonance.
By forcing more timesteps, you can see the amplitude decreasing (but it's rather slow, because this will clearly have a long time constant).
I simulated this netlist:
//V0 (Vin 0) vsource type=sine ampl=10 freq=159.154943K mag=10L1 (Vin Vout) inductor l=1uC1 (Vin Vout) capacitor c=1uR0 (Vout 0) resistor r=100K//ac ac start=159.154K stop=159.156K step=.001ac ac start=155K stop=160K step=.001tran tran stop=1 method=traponly maxstep=1/(2000*159K)
That number of timesteps is probably excessive - and I didn't wait for the simulation to end. If you look at the AC response, you can see that there's a very high Q on the resonsance. Looking at the beginning of the simulation (78million timepoints so far) shows the attached curve (obviously you can see the envelope).
In real life there would be some non-idealities in there...
Hi Mr Beckett,
Thanks for your help.
After reading your advise, I carried out 2 simulations again.
The first simulation is carried out with maxstep=1/(100*159K), as the original simulation setting. And, the second simulation is set up with maxstep=1/(2000*159K), following Mr Beckett's advice.
The figure of simulation results is as below.
It can be seen that, the simulation result is correct when maxstep=1/(2000*159K), and is wrong when maxstep=1/(100*159K).
The symbols are all turn on in the simulation result figure. It is indicated that, there are enough points among each Vout period, regardless of the maxstep value. So, I can't understand why simulation results are so different under the condition of different maxstep values.
Mr Beckett, could you help me please? Thank you very much.