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Amplifier

Complex baseband model of amplifier with noise and nonlinearities

Since R2020a

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  • Idealized baseband amplifier block icon

Libraries:
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.

Examples

Idealized Baseband Amplifier with Nonlinearity and Noise

Idealized Baseband Amplifier with Nonlinearity and Noise

The example shows how to use the idealized baseband library Amplifier block to amplify a signal with nonlinearity and noise. The Amplifier uses the Cubic Polynomial model with a Linear power gain of 10 dB, an Input IP3 nonlinearity of 30 dBm, and a Noise figure of 3 dB.

Ports

Input

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Input baseband signal, specified as a real scalar, real column, complex scalar, or complex column.

Data Types: double | single

Output

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Output baseband signal, specified as a real scalar, real column, complex scalar, or complex column. The output port mimics the properties of the input port. For example, if the input baseband signal is specified as a real scalar with a data type double, then the output baseband signal is also specified as a real signal with the data type double.

Data Types: double | single

Parameters

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Main Tab

Specify the amplifier nonlinearity model as one of the following:

  • cubic — The cubic polynomial model uses linear power gain to determine the linear coefficient of a third-order polynomial and either IP3, P1dB, or Psat to determine the third - order coefficient of the polynomial.

  • ampm — The AM/AM-AM/PM model uses a lookup table to calculate the amplifier power characteristics.

  • modified-rapp — The modified Rapp uses a normalized transfer function to calculate the amplifier power characteristics.

  • saleh — The Saleh model also uses a normalized transfer function to calculate the amplifier power characteristics.

For more information, see Nonlinearity Models in Idealized Amplifier Block.

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 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 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 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 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 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 and Type of Non-Linearity to OPsat.

  • 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.

  • 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.

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

For more information, see Plot Power Characteristics.

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.

The interp1 function with the linear method is employed to extrapolate and interpolate the data points specified in the lookup table. Furthermore, for extrapolating input data points that are less than the smallest specified input power value in the lookup table, the AM/AM extrapolation uses a slope of 1 and constant phase value equal to the phase of the smallest input power.

Dependencies

To enable this parameter, set Model to ampm.

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 or two-tuple vector.

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.

Type of noise, specified as one of the following:

  • noise-temperature — Noise temperature

  • NF — Noise figure

  • noise-factor — Noise factor

For more information, see Thermal Noise Simulations in Idealized Amplifier Block.

Dependencies

To enable this parameter, select Include Noise.

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 NF.

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 - When Seed source is set to user, 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 in the Seed source parameter.

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.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2020a

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See Also

Blocks

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