i have to make transient simulation of .wav file signal for my project. I tried to change general options for calculating but no results. I think my circuit is complicated for ltspice and simulation lasts forever. I attach scheme.
\$\begingroup\$
\$\endgroup\$
12
-
\$\begingroup\$ Please attach the image inline to the post. How long is your wave file? How many cores do you have in your computer running the simulation? \$\endgroup\$– AaronMay 11, 2020 at 19:07
-
\$\begingroup\$ my signal is a .wav file and it is stomach signal from sensor, it is like 25 minutes but i cut and use only 10 secs. i have 4 cores \$\endgroup\$– Adrian MMay 11, 2020 at 19:10
-
\$\begingroup\$ Vcc is 3.3V, correct? Op amps U2,3,7,8 have no bias. \$\endgroup\$– Bruce AbbottMay 11, 2020 at 19:27
-
\$\begingroup\$ what's your sample rate? And what is a "stomach signal"? When asked to plot a stomach signal, I would plot a straight line at 1 for the last decades, because that's the amount of stomach I have. \$\endgroup\$– Marcus MüllerMay 11, 2020 at 19:54
-
\$\begingroup\$ Do you need the 10 ns step size? \$\endgroup\$– HuismanMay 11, 2020 at 20:01
|
Show 7 more comments
2 Answers
\$\begingroup\$
\$\endgroup\$
3
As @Huisman hinted at:
Your sampling rate is 44.1 kHz, yet you're simulating this circuit with a simulation rate of 1/10ns = 100 MHz. That means for every time the input changes, 100 MHz / (44.1 kHz), i.e. more than 2000 simulation steps, are performed.
That is very likely far more than necessary. Try with maybe 1000 ns of step size and see whether that changes the result in any way. If it does: your system needs better low-pass characteristics – it really shouldn't change anything, considering your recordings can't even represent anything above 22.05 kHz.
answered May 11, 2020 at 20:27
-
\$\begingroup\$ If OP's using a
.wavthen imposing a timestep is not even necessary since the file itself has sampling which will act as a timestep limit. Moreover, OP's only using some analog filtering. Unless the model for the opamp is bad, the simulation would fly at the maximum allowable rate this way. It's always amazing to see how many people blame the tool for their usage. \$\endgroup\$ May 11, 2020 at 20:34 -
\$\begingroup\$ i do not blame ltspice, just looking for solution with circuit or how to optimize it \$\endgroup\$– Adrian MMay 11, 2020 at 20:37
-
1\$\begingroup\$ Point is, your .tran line suggest a very small step size \$\endgroup\$ May 11, 2020 at 20:43
\$\begingroup\$
\$\endgroup\$
You can try to modify the resolution of the simulation. If your step size/time interval is too small, your computer may be doing more work than needed to calculate the output. Your computer may be slowing the process down outside the software, however. If you have a slow CPU or are running many background tasks, it may cause some delays.
I would check out this question along with this post by LTSpice. I use MicroCap (which was just recently released for free) and I've yet to wait more than a few seconds for a simulation to finish. Definitely worth checking out.
