Dear all,
Hello,
This is my first time on your forum.
I am working on the electric equivalent circuit of acoustic and optic propagation phenomena.
I have been in need of a component (resistor for instance) whose value is a function of the supplied frequency.
I'm using a VAC source in AC sweep mode.
Can you help please?
Thank you
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* Test a frequency dependent resistor
*
V1 1 0 AC 1
R1 1 2 9
G1 2 0 LAPLACE {V(2,0)}={1/(1+0.01*s)}
.AC DEC 100 10 10K
.PROBE I(G1)
.END
Thanks a lot
Your welcome. Also, if you substitute IMG(0.159155*s) for s you can create an expression that's a function of the real variable f rather than the complex frequency variable s.
Hi, I also have a question related to that frequency controlled resistor.
To model a frequency-controlled resistor, I used the method including a non-linear laplace form voltage control current source "GLaplace" as your guys suggested.
I tried with a simple equation, R=1+f, when I do the AC sweep study in the PSPICE, the model works fine as I attached figure as AC sweep, the resistance (yellow line) change from 1 to 101 ohms when frequency changing from 1 to 100 Hz. And the voltage crossing that model is consistent with our concept. In AC sweep simulation, that model is working ok.
However when I simulate that in transient simulation with a simple 100Hz sin wave (Green line in "transient_study 2" is input 1V, 100Hz sinwave souce, red line is resistor voltage and should be a 0.5V sin wave and no phase shift compared with input source), as you could see, the resistance response of model is very inaccurate (yellow line in transient_study 1, the value should be R=1+100=101 ohms).
So I am not sure if that Glaplace model is useable in the trasient simulation.
Any suggenstions and help would be appreciated.
Thank you.
Your analysis is now in the time domain and the calculation of a function of s is different. See the section in your PSpice User Guide titled "Cautions and Recommendations for Simulation and Analysis" in the Analog Behavioral Modeling chapter.