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PSpice derivative not smooth

BertRAMAerts

This is my circuit:

What I do not understand is the un-stability of the derivative:

I would expect a flat line...  What can be wrong

  • BertRAMAerts
    0

    Of course a derivative of 200K=200000 is huge, atan(200000)-Pi/2=5E-6 so very very close to Pi/2.
    Taking a much bigger max timestep of 0.5usec instead of 0.01usec gives a better result with much less noise.
    Not sure why...

  • BertRAMAerts
    +1 in reply to BertRAMAerts

    It was just a setting: I made the relative tolerance 10 times smaller than the default value:

    and now the gain looks great even with very small timestep of 0.01 usec:

  • AyushD
    0 in reply to BertRAMAerts

    You just tighten the accuracy and hence smooth line.

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