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<rgaja...@vercet.com> 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
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