How to add a flicker noise source to a component ?

 Hi,

I made a verilog-a block to generate a flicker_noise dependent of the current circulating in the branch :

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

module flicker_source(nplus,nmoins,probep,probem);
output     nplus,nmoins;
input       probep,probem;
electrical nplus,nmoins,probep,probem;
 parameter real kf = 1.0;
 parameter real af = 1.0;
 parameter real ef = 1.0;
                
   analog begin
      I(nplus, nmoins) <+ flicker_noise(kf*pow(abs(I(probep,probem)),af),ef);
   end
endmodule

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But testing this block with a simple circuit, a resistor with a current source, I obtain incoherent results. In theory, if I apply a DC current to the resistor, I should obtain a 1/f noise around the DC. And if I apply just the pump at f0, I should obtain a 1/f noise around f0. But, it is not the case. In both cases, I obtain noise around the DC.

When I apply the DC and the pump at the same time, I obtain noise around DC and f0 but with incoherent levels.

Thinking the flicker_noise() function present a problem, I did another test using this function just to generate a constant 1/f noise (not current dependent). Then, I create another verilog-a block to read this fixed noise, read the current flowing through the resistor and multiply these two values to generate the final noise. The result is exactly the same.

My conclusion is that it exists a real problem with the simulator. Maybe, it's impossible to simulate cyclostationnary noise. But I hope I'm wrong and someone can give me the solution.

Regards,

Emmanuel

 Hi,

I made a verilog-a block to generate a flicker_noise dependent of the current circulating in the branch :

------------------------------------------------------------------------------------------------------

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

module flicker_source(nplus,nmoins,probep,probem);
output     nplus,nmoins;
input       probep,probem;
electrical nplus,nmoins,probep,probem;
 parameter real kf = 1.0;
 parameter real af = 1.0;
 parameter real ef = 1.0;
                
   analog begin
      I(nplus, nmoins) <+ flicker_noise(kf*pow(abs(I(probep,probem)),af),ef);
   end
endmodule

---------------------------------------------------------------------------------------------------------

But testing this block with a simple circuit, a resistor with a current source, I obtain incoherent results. In theory, if I apply a DC current to the resistor, I should obtain a 1/f noise around the DC. And if I apply just the pump at f0, I should obtain a 1/f noise around f0. But, it is not the case. In both cases, I obtain noise around the DC.

When I apply the DC and the pump at the same time, I obtain noise around DC and f0 but with incoherent levels.

Thinking the flicker_noise() function present a problem, I did another test using this function just to generate a constant 1/f noise (not current dependent). Then, I create another verilog-a block to read this fixed noise, read the current flowing through the resistor and multiply these two values to generate the final noise. The result is exactly the same.

My conclusion is that it exists a real problem with the simulator. Maybe, it's impossible to simulate cyclostationnary noise. But I hope I'm wrong and someone can give me the solution.

Regards,

Emmanuel