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Design Languages >> Verilog-AMS >> LRM on using probes on correlated noise
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Message started by Balaji Raman on Sep 18^th, 2013, 3:27am

Title: LRM on using probes on correlated noise
Post by Balaji Raman on Sep 18^th, 2013, 3:27am

Dear all,

Kindly answer the following query explained using an artificial Verilog A example.

Is it allowed to use a current or voltage probe in the RHS of a contribution statement, where the RHS is an expression containing an output of a noise function.

That is, consider n to be the output of a noise function. Next to the noise function statement, assume we have a contribution statement , which is generating a voltage or a current noise source using the variable n. Now, my question is if n can be multiplied by another current or voltage probe. Below are the statements pertaining to this scenario.

n = white_noise(pwr);
V(a,b) <+ V(e,f) * n;
V(c,d) <+ I(p)*n;

Thanks for your attention,
Balaji.

Title: Re: LRM on using probes on correlated noise
Post by Geoffrey_Coram on Nov 5^th, 2013, 8:19am

Some simulators/compilers are picky about what they allow you to do with white_noise: some don't even allow n = white_noise(pwr) -- or at least, they didn't some time ago when I last checked.

Some of them that do allow n = white_noise(pwr) convert this to
I(internal_noise_node) <+ V(internal_noise_node) + white_noise(pwr);
n = V(internal_noise_node);

in which case, it would be just fine to write
V(a,b) <+ V(e,f) * n;
V(c,d) <+ I(p)*n;

I don't think the LRM prohibits your expressions.