Difference between Qspice simulation results and other programs

Difference between Qspice simulation results and other programs. What’s this? Qspice calculates correctly, but other programs do not?
I have attached the simulation results to the folder.
GEN.txt (333.9 KB)
Gen.txt to Gen.zip


Pay attention to the high and low levels. This is the difference in the results.

I suspect that the bipolar transistor model in Qspice differs from the model in other Spice programs.
Where is the truth?

Where is the truth?

I would venture to say the truth is in the hardware circuit. Everything else is just a simulation : )

Why then use simulation at all if it is far from practice?

I’m affraid we’ve first to answer your first question: what simulator gives more accurate result.

From there we could devise which ones require attention.

Also, since the oscillator is in the megahertz range, this simulation will be off for any, even the most exact calculation done as it does take in account the non ideal nature of the reactive components. Which see, according to another topic in this forum, is hard to do a good simulation.

@bordodynov I study this case and it seems Tr in BJT model is the parameter in concern.
What I did was firstly remove all BJT model parameters, and run test in LTspice and Qspice, results is similar. I found that with only Tr=239.5n, it leads to largest different between them.
However, I am not familiar with this parameter and still reviewing how to reveal the effect of Tr to compare why this parameter perform so differently in between simulator.

This is an example only with TR in BJT model

This remove all BJT model parameters and run with default

Qspice and LTspice


Draft7.qsch (859 Bytes)