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Design Languages >> VHDL-AMS >> Modelling of a complex Impedance f(FREQUENCY)
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Message started by Menas on Jun 11^th, 2007, 10:40am

Title: Modelling of a complex Impedance f(FREQUENCY)
Post by Menas on Jun 11^th, 2007, 10:40am

Hello Everybody,

I'm using ADvance-MS from Mentor Graphics.

I have to model an Impedance which varies with the frequency. So I have created some functions to enable it (Bessel functions...etc...).
This is OK while a consider this impedance as a purely resistive impedance (ie. a real). But the point is that this impedance is in fact an Imaginary. So I tried to use the package MATH_COMPLEX, but the problem is that a QUANTITY must be real, so it's impossible to use complex numbers in simultaneous statements. I also tried things like i==Z*u'dot, but I'd like to see the impedance value as the Real part/imaginary part (ADVANCE MS allows it)
I have modelled a Ohmmetre in order to measure the U/I ratio, but it doesn't work, even if the impedance is real...(the ration is always equal to zero)
Should I use the FFT function provided in EZ Wave?

My question is : "How to measure a complex impedance in a AC analysis ?"
Can Someone help me ?

Title: Re: Modelling of a complex Impedance f(FREQUENCY)
Post by boe on Jun 12^th, 2007, 7:38am

Menas wrote on Jun 11^th, 2007, 10:40am:

My question is : "How to measure a complex impedance in a AC analysis ?"

Stimulating your model with a current source of 1 A, running an AC analysis and looking at the voltage across your model does not work?
BOE

Title: Re: Modelling of a complex Impedance f(FREQUENCY)
Post by Menas on Jun 12^th, 2007, 9:00am

Thank you very much ! I think it's OK.