Re: AWGN in Cadence?

Partha,

Thanks for your reply.  I'm not too familiar with Verilog, but I managed to
modify the Cadence Verilog-A noise_src module to make the random number
generator gaussian.  However, this requires me to add a noise source in
series with all the nodes to which I want to add noise.  Is there a better
way to do this?  For example, is there an operator other than "<+" in
Verilog that will simply provide an additive voltage source to an existing
node?

In addition, does the following Verilog-A module accurately (realistically)
model AWGN if put in series with an existing node?

`include "discipline.h"
`include "constants.h"

module noise_src(vout,ref);
 output vout;
 input ref;
 electrical vout,ref;
 parameter real amp = 0.2 from [0:inf);
 parameter real att = 10 from [0:inf);
 integer seed;

 analog begin
  @ (initial_step) begin
   seed=23;
  end

  V(vout,ref) <+ amp * $dist_normal(seed,0,1)/att;
  $display ("seed is %d",seed);
 end

endmodule

Thanks,
-Jason

"Partha" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Jason,
> There are multiple ways of doing this,
> If the simulator is spectre
>
> 1. Using verilog-A noise functions
> 2. Adding a white noise current source
> 3. Adding a white noise voltage source
>
> I beleive i saw the above sometime before @ source link, i am not able
> to recollect it now, seach sourcelink for details
>
> If you use spectre-Rf as your simulator, you could do a PNoise nalysis
> by adding sources of noise on the nodes(port components?)
>
>
>
> "Jason D. Bakos" <[EMAIL PROTECTED]> wrote in message
news:<[EMAIL PROTECTED]>...
> > Hello!
> >
> > Anyone have a way to add additive white Gaussian noise to nodes in a
> > Virtuoso schematic and can be simulated in Affirma/Spectre/Analog
Artist?
> >
> > Thanks,
> > -Jason