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M-PAM Modulator Baseband

Modulate using M-ary pulse amplitude modulation

  • M-PAM Modulator Baseband block

Libraries:
Communications Toolbox / Modulation / Digital Baseband Modulation / AM

Description

The M-PAM Modulator Baseband block modulates a signal by using M-ary pulse amplitude modulation. The output is a baseband representation of the modulated signal.

Note

All values of power assume a nominal impedance of 1 ohm.

Examples

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The doc_pam_mod model uses the M-PAM Modulator Baseband block to modulate input data. Observe changes in the constellation size and scaling for various normalization methods and modulation orders.

A Random Integer Generator block generates a vector of integers over the range [0, M-1] as input for a modulator that applies M-PAM.

Update mask parameters in the M-PAM Modulator Baseband block. Set the modulation order to 8 and the default minimum distance between symbols normalization method. Click the View Constellation parameter on the M-PAM Modulator Baseband block mask to observe the constellation.

Update the M-PAM Modulator Baseband block mask to set the average power normalization method. Click the View Constellation parameter on the M-PAM Modulator Baseband block mask to observe the change in the constellation scaling.

Update the M-PAM Modulator Baseband block mask to set the peak power normalization method. Click the View Constellation parameter on the M-PAM Modulator Baseband block mask to observe the change in the constellation scaling.

Update the M-PAM Modulator Baseband block mask to set the modulation order to 4. Click the View Constellation parameter on the M-PAM Modulator Baseband block mask to observe the constellation.

Update the M-PAM Modulator Baseband block mask to set the modulation order to 2. Click the View Constellation parameter on the M-PAM Modulator Baseband block mask to observe the constellation.

Ports

Input

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Input signal, specified as a scalar or column vector. The input data must be binary values or integers in the range [0, (M – 1)], where M is the modulation order as specified by the M-ary number parameter. This port is unnamed on the block.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean

Output

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M-PAM-modulated baseband signal, returned as a scalar or column vector. Use the Output data type parameter to specify the output data type. This port is unnamed on the block.

Data Types: single | double | fixed point

Parameters

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To edit block parameters interactively, use the Property Inspector. From the Simulink® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Main

Modulation order, specified as a positive, even integer. The modulation order, M, specifies the number of points in the signal constellation. The block scales the signal constellation based on how you set the Normalization method parameter. For more information, see Constellation Size and Scaling.

Type of input value, specified as Integer or Bit. When you set this parameter to Bit, the M-ary number parameter must be 2K for some positive integer K.

Mapping order of the symbols, specified as Gray or Binary. This parameter indicates how the block maps binary words to points of the signal constellation.

  • When you set this parameter to Binary, the block uses binary-coded constellation.

  • When you set this parameter to Gray, the block uses a Gray-coded constellation.

Scaling method for the constellation, specified as Min. distance between symbols, Average Power, or Peak Power. For more information, see Constellation Size and Scaling.

Distance between the two nearest constellation points, specified as a positive scalar.

Dependencies

This parameter appears when you set Normalization method to Min. distance between symbols.

Average power of the symbols in the constellation in watts, specified as a positive scalar. Power values assume a nominal impedance of 1 ohm.

Dependencies

This parameter appears when you set Normalization method to Average Power.

Maximum power of the symbols in the constellation in watts, specified as a positive scalar. Power values assume a nominal impedance of 1 ohm.

Dependencies

This parameter appears when you set Normalization method to Peak Power.

Click View Constellation on the block mask to visualize a signal constellation for the specified block parameters. Before viewing a constellation, apply the parameter settings. For more information, see View Constellation of Modulator Block.

Data Types

Output data type, specified as double, single, fixdt(1,16), fixdt(1,16,0), Inherit: Inherit via back propagation, or <data type expression>.

  • fixdt(1,16), fixdt(1,16,0), or <data type expression> enables parameters in which you can further specify details.

  • Inherit: Inherit via back propagation sets the output data type and scaling to match the following block.

The Data Type Assistant helps you set data attributes. To use the Data Type Assistant, click Show data type assistant . For more information, see Specify Data Types Using Data Type Assistant (Simulink).

Block Characteristics

Data Types

Boolean | double | fixed pointa, b | integer | single

Multidimensional Signals

no

Variable-Size Signals

yes

a ufix(1) at the input if ''input type'' is set to ''bit''. ufix(ceil(log2(M))) at input if ''input type'' is set to ''integer'' for M-ary modulation.

b Fixed-point outputs must be signed.

Algorithms

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Extended Capabilities

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

Version History

Introduced before R2006a