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13th February 2017, 23:42 #1
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[Moved]: How to simulate DC Nonlinear model?
Hi,
I have an equation that describes the linearity of my amplifier. and I want to make a plot based on the equation. How could I do that in ADS?
this the equation I have vo=a1+a2vi+a3vi^2, and I want to plot vo vs vi...
Please help,
thanks

13th February 2017, 23:42

14th February 2017, 02:29 #2
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Re: How to simulate DC Nonlinear model?
Can you create a lissajous figure? It's the natural choice.
Excellent for observing whether your amplifier introduces distortion.

14th February 2017, 16:32 #3
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Re: How to simulate DC Nonlinear model?
It is very easy.
Use SDD(Symbolically Define Device) or VerilogA.
http://edadocs.software.keysight.com...efined+Devices
http://edadocs.software.keysight.com...he+SDD+and+UCM

13th March 2017, 21:38 #4
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Re: How to simulate DC Nonlinear model?
Hopefully it's not too late to get back to you. Thank you for your help. The SDD example is really helpful.
I tried out the example, but it doesn't work as what I expect. Compression point, OIP2, and OIP3 do not match to my original amplifier.
I have the equations set up as follows.. K1, K2, and K3 are calculated base on gain, OIP2, and OIP3. Do I input anything wrong here?

15th March 2017, 14:28 #5
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Nonlinear model of amplifier simulation using SDD
Hi all,
I would like to come up with a DC nonlinear model of an amplifier. I calculated k1, k2, and k3 based on gain, OIP2, and OIP3 of the amp. And now, I need to simulate the output voltage equation vo=k1vi+k2vi^2+k3vi^3. I use SDD2P block to simulate(as shown in the pictures below), but I could not get similar OIP2 and OIP3 values by doing HB simulations. Does anyone know what I've done wrong in the simulation setup?
Thank you so much!

15th March 2017, 14:28

18th March 2017, 11:28 #6
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Re: Nonlinear model of amplifier simulation using SDD
Show me equations for k1, k2 and k3 you use.
http://edadocs.software.keysight.com...pageId=5923594
And you use "vi" in SDD without defining it.Last edited by pancho_hideboo; 18th March 2017 at 11:37.

20th March 2017, 07:08 #7

20th March 2017, 18:17 #8
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20th March 2017, 18:17

21st March 2017, 02:57 #9
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Re: Nonlinear model of amplifier simulation using SDD
No.
I request equations for k1, k2 and k3.

21st March 2017, 15:24 #10
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Re: Nonlinear model of amplifier simulation using SDD

21st March 2017, 16:22 #11
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Re: Nonlinear model of amplifier simulation using SDD
First, set k2=0.
Can you get reasonable results when k2=0 ?
I think your equations for k2 and k3 are very suspicious.
See http://www.designersguide.org/Model...rfsystems.pdf
There are many definition of IM2.
And IM2 is out of band.
Show me definition of your IM2.Last edited by pancho_hideboo; 21st March 2017 at 16:46.
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