What happens when you make the steady state tolerance 10 times smaller? (Apparently it's some kind of steady state analysis, I never knew there were free simulators supporting that.)
A zero tolerance makes no sense, maybe it uses the default tolerance whenever the tolerance is set to a value that's <= 0, instead of giving a normal error message.
It is suggested in the help menue to set it zero, I also tried just to reduce it.
Last edited:
What are you feeding this with? Bit rate?
If you have a ultra clean amp, great. However it will simply show up the other components around it.. (IIRC 24bit DAC has a noise floor of -144dBS).
Yes the sim will help, but in the end you need to start making prototypes to really find the noise.
If you have a ultra clean amp, great. However it will simply show up the other components around it.. (IIRC 24bit DAC has a noise floor of -144dBS).
Yes the sim will help, but in the end you need to start making prototypes to really find the noise.
I see. Are there any other tolerance settings hidden anywhere? In Spice-like simulators, reltol is usually the most important one.
Does it help to set the "Number of time points" to a power of 2 and "Time step ratio" to its reciprocal?
http://www.spectrum-soft.com/faq/help/faq195.shtm
http://www.spectrum-soft.com/faq/help/faq195.shtm
With every doubling, it gets better, however at 4096 it seems hitting the wall again -208dB...
Now I try 8182, will take some time.
Now I try 8182, will take some time.
I now try time step ratio 0.01m
Takes very long time…
Last edited:
Page 941 of http://www.spectrum-soft.com/download/rm12.pdf shows that there is a reltol and it can even be changed over time, if needed.
My guess is that you will need something of the order of 1E-6 or less.
The PSS option could also be interesting to try.
My guess is that you will need something of the order of 1E-6 or less.
The PSS option could also be interesting to try.
Small success
Checked the box „periodic steady state“
Simulation of the sine source now gives -248dB.
Independent from those changes, transient analysis of the sine source shows flat harmonics at -250dB, so maybe this is the real limit.
Transient analysis of the circuit shows -235dB flat harmonics.
Checked the box „periodic steady state“
Simulation of the sine source now gives -248dB.
Independent from those changes, transient analysis of the sine source shows flat harmonics at -250dB, so maybe this is the real limit.
Transient analysis of the circuit shows -235dB flat harmonics.