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Design Languages >> Verilog-AMS >> implement laplace_zp function from measurements
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Message started by Pavel on Apr 18^th, 2007, 4:05am

Title: implement laplace_zp function from measurements
Post by Pavel on Apr 18^th, 2007, 4:05am

Hello,

How to implement laplace_zp function from "pole-zero" analysis.
The output from this analysis is done as table

qfactor poles (Hz)
0.5 123.6
-0.5 4.5e+6
. .
. .

How to transform this data in paires (real, imaginary), required by laplace_zp function?

Regards,

Pavel.

Title: Re: implement laplace_zp function from measurement
Post by Saran on Apr 25^th, 2007, 8:26am

laplace_zp syntax is laplace_zp(input, {-z1,0,-z2,0}{-p1,0,-p2,0}) for a transfer function ((1+s/z1)(1+s/z2))/((1+s/p1)(1+s/p2)) where p1,p2,z1,z2 are real poles and zeros. You can get more information from LRM or a basic text book.

However, if you are trying to implement a filter response based on poles and Q-factor values, then wouldn't it be easy to use laplace_nd on the transfer function?

For instance, assume you have a biquad filter that is given by the TF w^2/(s^2+ s(w/Q)+w^2), w is the pole location(freq) and Q is the Q-factor. Use laplace_nd directly on this function.

I guess what I am trying to say is, depends on what you want to do! Hope this helps.

Title: Re: implement laplace_zp function from measurement
Post by Pavel on Apr 26^th, 2007, 3:15am

What I want to do is create model in verilog-A of operational amplifier.

I did zero-pole analysis of this OpAmp.
The result of this anaysis is extracted poles and zeros in form of pairs
(qfactor, pole) and conseuntly (qfactor, zero).

How can I use these results to create OpAmp model in verilog-A.
If you understand what I mean, could you, please, create lapalce function for following case:

qfactor zeros (Hz)
-0.5 1.81E+07
-0.5 1.84E+07
0.5 2.39E+07
-0.5 1.06E+08

qfactor poles (Hz)
0.5 5.727
0.5 1.24E+07
0.5 1.84E+07
0.5 2.38E+07
-0.5 3.57E+07

Regards,

Pavel