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Model amplifier in RF systems

**Library:**SimRF / Circuit Envelope / Elements

Use the Amplifier block to model a linear or
nonlinear amplifier, with or without noise. Defining the amplifier
gain using a data source also defines input data visualization and
modeling. Use the **Main** tab parameters to specify
amplifier gain and noise using data sheet values, standard `s2p`

files,
S-parameters, or circuit envelope polynomial coefficients.

The amplifier is implemented as a polynomial, voltage-controlled
voltage source (VCVS). The VCVS includes nonlinearities that are described
using parameters listed in the **Nonlinearity** tab.
To model linear amplification, the amplifier implements the relation *V*_{out} =
a_{1}**V*_{in} between
the input and output voltages. The input voltage is *V*_{i}(*t*)
= *A*_{i}(*t*)e^{jωt},
and the output voltage is *V*_{o}(*t*)
= *A*_{o}(*t*)e^{jωt} at
each carrier *w* = 2π*f* in
the SimRF™ environment.

Nonlinear amplification is modeled as a polynomial (with the saturation power computed automatically). It also produces additional intermodulation frequencies.

[1] Gonzalez, Guillermo. "Microwave Transistor Amplifiers: Analysis and Design", Englewood Cliffs, N.J.: Prentice-Hall, 1984.

[2] Grob, Siegfried and Juergen Lindner. "Polynomial
Model Derivation of Nonlinear Amplifiers, *Department of
Information Technology*, University of Ulm, Germany.

[3] Kundert, Ken. "Accurate and Rapid
Measurement of IP _{2} and IP _{3}", *The
Designers Guide Community*, Version 1b, May 22, 2002. http://www.designers-guide.org/analysis/intercept-point.pdf.

[4] Pozar, David M. "Microwave Engineering", Hoboken NJ: John Wiley & Sons, 2005.

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