# Amplifier

Complex baseband model of amplifier with noise and nonlinearities

• Library:
• RF Blockset / Idealized Baseband

## Description

The Amplifier block generates a complex baseband model of an amplifier with thermal noise. This block provides four nonlinearity models and three options to specify noise representation.

### Note

This block assumes a nominal impedance of 1 ohm.

## Parameters

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### Main Tab

Specify the amplifier nonlinearity model as one of the following:

• `Cubic polynomial`

• `AM/AM - AM/PM`

• `Modified Rapp`

• `Saleh`

Linear gain, specified as a scalar in dB.

Third order nonlinearity type, specified as `IIP3`, `OIP3`, `IP1dB`, `OP1dB`, `IPsat`, or `OPsat`.

Input third-order intercept point, specified as a real positive number in dBm.

#### Dependencies

To enable this parameter, set Model to ```Cubic polynomial``` and Type of Non-Linearity to `IIP3`.

Output third-order intercept point, specified as a real positive number in dBm.

#### Dependencies

To enable this parameter, set Model to ```Cubic polynomial``` and Type of Non-Linearity to `OIP3`.

Input 1 dB compression point, specified as a real positive number in dBm.

#### Dependencies

To enable this parameter, set Model to ```Cubic polynomial``` and Type of Non-Linearity to `IP1dB`.

Output 1 dB compression point, specified as a real positive number in dBm.

#### Dependencies

To enable this parameter, set Model to ```Cubic polynomial``` and Type of Non-Linearity to `OP1dB`.

Input saturation point, specified as a real positive number in dBm.

#### Dependencies

To enable this parameter, set Model to ```Cubic polynomial``` and Type of Non-Linearity to `IPsat`.

Output saturation point, specified as a positive real number in dBm.

#### Dependencies

To enable this parameter, set Model to ```Cubic polynomial``` and Type of Non-Linearity to `OPsat`.

• `Interpreted execution` – Simulate model using the MATLAB® interpreter. This option shortens startup time speed, but the speed of the subsequent simulations is slower than `Code generation`. In this mode, you can debug the source code of the block.

• `Code generation` – Simulate model using generated C code. The first time you run a simulation, Simulink® generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change. This option requires additional startup time, but the speed of the subsequent simulations is faster than ```Interpreted execution```.

This button plots the power characteristics based on the parameters specified on the Main tab.

Table lookup entries specified as a real M-by-3 matrix. This table expresses the model output power dBm level in matrix column 2 and the model phase change in degrees in matrix column 3 as related to the absolute value of the input signal power of matrix column 1 for the AM/AM - AM/PM model. The column 1 input power must increase monotonically.

#### Dependencies

To enable this parameter, set Model to ```AM/AM - AM/PM```

Voltage output saturation level, specified as a real positive number in dBm.

#### Dependencies

To enable this parameter, set Model to ```Modified Rapp```

Magnitude smoothness factor for the `Modified Rapp` amplifier model AM/AM calculations, specified as a positive real number.

#### Dependencies

To enable this parameter, set Model to ```Modified Rapp```

Phase gain for the `Modified Rapp` amplifier model AM/PM calculations, specified as a real scalar in radians.

#### Dependencies

To enable this parameter, set Model to ```Modified Rapp```

Phase saturation for the `Modified Rapp` amplifier model AM/PM calculations, specified as a positive real number.

#### Dependencies

To enable this parameter, set Model to ```Modified Rapp```

Phase smoothness factor for the `Modified Rapp` amplifier model AM/PM calculations, specified as a positive real number.

#### Dependencies

To enable this parameter, set Model to ```Modified Rapp```

Scaling factor for input signal level for the `Saleh` amplifier model, specified as a nonnegative real number in dB.

#### Dependencies

To enable this parameter, set Model to `Saleh`

AM/AM two-tuple conversion parameters for `Saleh` amplifier model, specified as a two-element vector of nonnegative real numbers.

#### Dependencies

To enable this parameter, set Model to `Saleh`

`AM/PM` two-tuple conversion parameters for `Saleh` amplifier model, specified as a two-element vector of nonnegative real numbers.

#### Dependencies

To enable this parameter, set Model to `Saleh`

Scaling factor for output signal level for `Saleh` amplifier model, specified as nonnegative real number in dB.

#### Dependencies

To enable this parameter, set Model to `Saleh`

### Noise Tab

Select this parameter to add system noise to the input signal. Once you select this parameter, the parameters associated with the Noise tab are displayed.

Noise descriptive type, specified as `Noise temperature`, `Noise figure`, or `Noise factor`.

Noise temperature to model noise in the amplifier, specified as a nonnegative real number in degrees (K).

#### Dependencies

To enable this parameter, select Include noise and set Specify noise type to ```Noise temperature```.

Noise figure to model noise in the amplifier, specified as a nonnegative real number in dB.

#### Dependencies

To enable this parameter, select Include noise and set Specify noise type to `Noise figure`.

Noise factor to model noise in the amplifier, specified as a positive integer scalar greater than or equal to 1

#### Dependencies

To enable this parameter, select Include noise and set Specify noise type to `Noise factor`.

Source of initial seed used to prepare the Gaussian random number noise generator, specified as one of the following:

• `Auto` - When Seed source is set to `Auto`, seeds for each amplifier instance are generated using a random number generator. The reset method of the instance has no effect.

• `User specified` - When Seed source is set to `User specified`, the value provided in the Seed is used to initialize the random number generator and the reset method resets the random number generator using the Seed property value.

Seed for the random number generator, specified as a nonnegative integer less than 232. Use this value to initialize the random number generator.

#### Dependencies

To enable this parameter, click Include noise check box and choose `User specified` in the Seed source parameter.

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## References

[1] Razavi, Behzad. “Basic Concepts “ in RF Microelectronics, 2nd edition, Prentice Hall, 2012.

[2] Rapp, C., “Effects of HPA-Nonlinearity on a 4-DPSK/OFDM-Signal for a Digital Sound Broadcasting System.” Proceedings of the Second European Conference on Satellite Communications, Liege, Belgium, Oct. 22-24, 1991, pp. 179-184.

[3] Saleh, A.A.M., “Frequency-independent and frequency-dependent nonlinear models of TWT amplifiers.” IEEE Trans. Communications, vol. COM-29, pp.1715-1720, November 1981.

[4] IEEE 802.11-09/0296r16. “TGad Evaluation Methodology.“ Institute of Electrical and Electronics Engineers.https://www.ieee.org/

[5] Kundert, Ken.“ Accurate and Rapid Measurement of IP2 and IP3,“ The Designer Guide Community, May 22, 2002.