In this case, the solver will not need to add extra steps internally. You specified a sin generator, whose output is a simple function of time, and a resistor. The whole circuit is memoryless. At 60Hz, the period is just 16.6ms. With a 10ms step size, of course you're going to see an aliased waveform. You must decrease your step size.
OTOH, if you add a capacitor and/or inductor to that circuit, then the transient solver might decrease its step size automatically. Or it might not. Bottom-line: decrease your step size. On Tue, Sep 21, 2010 at 10:27 AM, Chris Cole <[email protected]> wrote: >> >> On Tuesday 21 September 2010, Chris Cole wrote: >> >>> >>> I get a normal sine wave output, >>> but when the frequency increases, the wave changes >>> considerably and starts to turn into a triangle wave...I'm >>> not sure what I'm doing wrong, but this is strange. >>> >> >> In the tran command (tran 10m 10 1) you asked it to strobe at 1 >> second intervals. So, no matter what the signal, you get >> samples 1 second apart. >> >> If you add "trace all" to the tran command you will see all of >> the samples, which should produce a smoother waveform. >> >> How it works is a throwback to when people actually looked at >> ASCII plots. It needs to change to make "trace all" the >> default, and have the strobe interval require a keyword "strobe" >> like spectre does. >> >> The actual time stepping is determined internally. There will >> be extra steps internally if needed to get a proper simulation, >> but they are not displayed unless you ask for them. >> >> >> > > Even with the "trace all" added to my tran command: > > #!/bin/bash > gnucap <<EOF > build > Vcc ( vin 0 ) sin offset=0. amplitude=24. frequency=60. > r1 ( vin 0 ) 1.K > > list > print tran v(Vcc) > tran 10m 10 1 trace all > ac_test.gwave > !gwave ac_test.gwave > EOF > rm ac_test.gwave > > > I get a crazy waveform (attached) > > > Chris > > > > _______________________________________________ > geda-user mailing list > [email protected] > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > > _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
