Hi The “fun part” of harmonic balance is making sure you are not off in a corner case where the results are not as good as they might otherwise be. Maybe not as much an issue for a VCO as for some other structures.
Bob > On Oct 28, 2017, at 7:36 AM, Rafael Gajanec <[email protected]> wrote: > > Hi Attila, > > On 27-Oct-17 8:25 PM, Attila Kinali wrote: >> Hi Rafael >> >> On Sun, 22 Oct 2017 17:20:52 +0200 >> Rafael Gajanec<[email protected]> wrote: >> >>> you haven't specified what sort of circuits would you like to simulate, >> Simplified, they are differential amplifiers driven into saturation. >> A bit more detailed, I am looking at ring oscillator stages and >> sine-to-square >> conversion circuits and their behaviour regarding various key factors >> (note: I am not sure what the key factors are, yet) > Oscillator design - that's what I found HB simulation particularly useful > for. It gives you almost instant results, compared to the transient > simulation, say 10 seconds instead of 5 hours! Just imagine what it means if > you are trying to tune several parameters of an oscillator... The only other > reasonably fast and accurate way I can think of is to build the bloody > circuit and measure it using some expensive equipment. >> >>> but maybe the answer is Harmonic Balance. >> Hmm.. I didn't know about Harmonic Balance. I have some reading up to do. >> Thanks! >> >>> HSPICE from Synopsis and ADS from Keysight (which I use) also have the >>> HB engine. >> I am mostly using ngpsice, because it's very easy to script (I have a bunch >> of perl scripts that feed simulations into a Grid Engine cluster, extract >> data and analyzse it). Is there any big advantage of the commercial spice >> engines that would make them worth considering? And would the license alow >> to run hundreds of instances in parallel? >> (Yes, I am doing crazy things :-) > Attached are some results of a simple transient simulation using Hspice M > 2017.03, BBspice A/D 5.2.3 and ADS 2016.01. It's basically *V1 1 0 SIN 0 1 > 1Meg *and then *.FOUR 1Meg V(1)* in Hspice, VspecTran in ADS and spectra > computed using postprocessor in BBspice and ADS. As you can see, there are > some differences... To be fair, possibly there are some simulator-specific > settings/methods that could improve the results and you should figure it out > yourself what's the way to get the best results from your spice. See > http://www.audio-perfection.com/spice-ltspice/distortion-measurements-with-ltspice.html > > Commercial spice engines may have lower computational noise and shorter > simulation times. For example my out-dated BBspice (which is commercial too > by the way) crashed several times before I got some results, while it used > little RAM and only about 10-12% of available processor resources... I > intended to get you Pspice results of this simulation as well, but I gave up > after half an hour and about 1% of progress. > >> >> Attila Kinali > > Best regards, > Rafael Gajanec > <Hspice.png><BBspice.png><ADS.png>_______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
