Hi,guys
I'm modeling a ADC.However,I meet a problem when to model a random source.I need a 255 outputs Gaussian source,and I find it difficult to realize that using "$rdist_normal(seed,mean,deviation)".
Is there anybody who can help me?
Thanks very much!

Hi,

What do you mean when saying 255 outputs Gaussian source? What do you get using your code?

Is it correct for the code
V(offset[i]) <+ V(result[i]);
result is defined as real. I don't know what the compiler/simulator do with the above statement.

Yawei

But I think you need two integers, one for the loop index and a second for the seed; as it is,
 V(offset[1]) = $rdist_normal(1, mean, dev)

That is, the call to $rdist_normal that sets output[1] is always made with the seed=1, so it will get the same value for each and every timepoint.

We can't help you if we don't understand what you are trying to do.

Are you sure you want a new $rdist value for *every* timepoint?

Perhaps you want to use a clock input, or a timer event, to signal when to generate new random values.

integer i, myseed;
genvar j;
@(initial_step)
 myseed = 0;

@(timer(0,1u)) begin
 for (i=1; i <=256; i++) begin
   result[i] = $rdist_normal(myseed, mean, dev);
 end
end

for (j=1; j <=256; j++) begin
 V(offset[j]) <+ transition(result[j], 0, 1n, 1n);
end

Oh, if the voltages are stable (ie, don't change in time, but are picked randomly at time zero), then

integer i, myseed;
genvar j;
@(initial_step) begin
myseed = 0;
for (i=1; i <=256; i++) begin
  result[i] = $rdist_normal(myseed, mean, dev);
end
end

for (j=1; j <=256; j++) begin
V(offset[j]) <+ result[j];
end