As a designer who is more acquainted with BSIM3+ simulation models for integrated circuits, I am interested in running transient noise sims. Does QSPICE have this functionality? I haven’t used LTSpice in-depth, so I’m unaware whether this was an option in the original simulator. Does anyone have the answer, or have a simple way to emulate an uncorrelated tran noise sim similar to spectre or hspice? Thanks!
QSPICE will handle stochastic noise of the linearized circuit from first principles, but semiconductor models can be decorated with flicker noise.
Normally, it’s used for looking at the noise of an amplifier, i.e., one specifies an input and output.
But you can have it just report the noise across an open circuit resistor. There’s an example included in the release, Noise.qsch, that shows (i) the stochastic noise of a resistor and (ii) how to make a resistor with noise below the Johnson-Nyquist limit of sqrt(4·k·T·R·BW).
–Mike
While this does generate a pseudo-random noise source, it does not generate an uncorrelated noise source for multiple sources (random() moves together).
Give each instance of random() a different offset to uncorrelate.
Hi @bordodynov,
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May I ask the logic of this random generator?
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Just wondering if this is close to gaussian noise or if its related to different kind of noise distribution?
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What will be the recommended method to tune this?
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to uncorrelate the noise, should we change the “dt” value or change the 2345?
Thanks
The author of this formula is Helmut Senevald. This is an attempt to make Gaussian noise. If you average this noise, you will get the value of parameter A. You can change the dt and/or Ft. Based on this source, I made a new one, equal to the sum of similar sources with Ft parameters that are multiples of irrational numbers. After all, it is known that if you add up several random variables, the distribution of the sum will tend to be Gaussian. However, this increases the counting time.
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