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Design Languages >> Verilog-AMS >> report a bug: laplace function does not support ac analysis
https://designers-guide.org/forum/YaBB.pl?num=1222089381

Message started by nus_lin on Sep 22^nd, 2008, 6:16am

Title: report a bug: laplace function does not support ac analysis
Post by nus_lin on Sep 22^nd, 2008, 6:16am

hello, guys.

i just found that if any branch is defined by laplace function, then its contribution will be ignored during ac analysis. can you tell me how to solve this problem?

example:

`include "constants.vams"
`include "disciplines.vams"

module S_gm(Vi,Vo);

inout Vi,Vo;
electrical Vi,Vo;

analog begin

V(Vo) <+ laplace_np(V(Vi),{1},{-p1,0});

end

endmodule

Title: Re: report a bug: laplace function does not support ac analysis
Post by sheldon on Sep 22^nd, 2008, 6:44am

It works fine for me. For a simple example
a constant term and frequency dependent
term got the attached results with the following
code

`include "constants.vams"
`include "disciplines.vams"

module test(Vi,Vo);
inout Vi,Vo;
electrical Vi,Vo;

parameter real p1=1 ;

analog begin

I(Vo) <+ 0.001 * laplace_np(V(Vi),{1},{-(2*`M_PI*p1),0});
I(Vo) <+ 0.001 * V(Vi) ;

end

endmodule

Title: Re: report a bug: laplace function does not support ac analysis
Post by nus_lin on Sep 22^nd, 2008, 7:06am

hi, sheldon, thank you. i tried your code too, but it doesn;t work in my machine. may i ask which design tools do you use?

Title: Re: report a bug: laplace function does not support ac analysis
Post by sheldon on Sep 30^th, 2008, 12:53am

Nus_lin,

Spectre

Best Regards,

Sheldon