Re: AWGN in Cadence?

Jason,

 I am also not so familiar with verilog-A , but I believe there is a 
ready-made function white_noise

 The way I would do it is with a resistor and a VCVS, because I find it 
more readable to have everything in the schematic rather than in 
verilog-A code, when practical.


Jason D. Bakos wrote:
> 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