Learn more about RF Blockset

Modeling RF Components

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Adding RF Blocks to a Model Connecting Model Blocks

Adding RF Blocks to a Model

You can include blocks from the RF Blockset Physical and Mathematical libraries in a Simulink model. For more information on the libraries and the available RF blocks, see RF Blockset Libraries.

This section contains the following topics:

• Input Signal Requirements

• How to Add RF Blocks to a Model

Input Signal Requirements

Most RF Blockset blocks only support complex single-channel signals. The signals can be either sample-based or frame-based. The following blocks have this requirement:

• All Physical blocks

• Mathematical Amplifier and Mixer blocks

You can model the effect of these components on a multichannel signal as follows:

1. Use a Simulink Demux block to split the multichannel signal into single-channel signals.

2. Create duplicate RF models, with one model for each channel, and pass each single-channel signal into a separate model.

3. Use a Simulink Mux block multiplex the signals at the output of the RF models.

How to Add RF Blocks to a Model

To add RF blocks to a Simulink model:

1. Type rflib at the MATLAB prompt to open the RF Blockset library.

2. Navigate to the desired library or sublibrary.

3. Drag instances of RF Blockset blocks into the model window using the mouse.

Note   You can also access RF Blockset blocks and other Simulink blocks from the Simulink Library Browser window. Open this window by typing simulink at the MATLAB prompt. Add blocks to the model by dragging them from this window and dropping them into the model window.

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Connecting Model Blocks

You follow the same procedure for connecting RF Blockset blocks as for connecting Simulink blocks: you click a port and drag the mouse to draw a line to another port on a different block. For more information on connecting blocks, see Connecting Blocks in the Model Window in the Simulink documentation.

You can only connect blocks that use the same type of signal. RF Blockset Physical blocks use different types of signals than Mathematical blocks, and are represented graphically by a different port style. Therefore, you can freely connect pairs of Mathematical modeling blocks. You can also freely connect pairs of Physical modeling blocks. However, you cannot directly connect Physical blocks to Mathematical blocks. Instead, you must use the Input Port and Output Port blocks to bridge them.

For more information on the RF Blockset libraries, including how to open the libraries and a description of the available blocks, see RF Blockset Libraries.

This section contains the following topics:

• Connecting Mathematical Blocks

• Connecting Physical Blocks

• Bridging Physical and Mathematical Blocks

Connecting Mathematical Blocks

The RF Blockset Mathematical blocks use the same input and output ports as standard Simulink blocks. These ports show the direction of the signal at the port, as shown in the following diagram.

Similar to standard Simulink blocks, you draw lines between the ports of the Mathematical modeling blocks, called signal lines, to represent signals that are inputs to and outputs from the mathematical functions represented by the blocks. Therefore, you can connect Simulink, Signal Processing Blockset, and RF Blockset mathematical blocks by drawing signal lines between their ports.

You can connect a port to multiple ports by branching the signal line, or you can leave a port unconnected. For more information on connecting blocks, see Connecting Blocks in the Model Window in the Simulink documentation.

Connecting Physical Blocks

The RF Blockset Physical blocks have specialized connector ports. These ports only represent physical connections; they do not imply signal direction.

The lines you draw between the physical modeling blocks, called connection lines, represent physical connections among the block components. Connection lines appear as solid black when connected and as dashed red lines when either end is unconnected.

You can draw connection lines only between the connector ports of physical modeling blocks. You cannot branch these connection lines. You cannot leave connector ports unconnected.

Bridging Physical and Mathematical Blocks

The blockset provides the Input Port and Output Port blocks to connect the physical and mathematical parts of the model. These blocks convert mathematical signals to and from the physical modeling environment.

The Input Port and Output Port blocks have one of each kind of connector port: a standard Simulink style input port and a physical modeling port. These ports are shown in the following figure:

The Input Port and Output Port blocks must bound a physical subsystem to connect it to the mathematical part of a model.

For example, a simple RF model of a coaxial transmission line might resemble the following figure.

The Microstrip Transmission Line block uses an Input Port block to get its white noise input from a Random Source block, and an Output Port block to pass its output to a Spectrum Scope block. The Random Source and Spectrum Scope blocks are from Signal Processing Blockset library.

For information on how RF Blockset software converts mathematical signals to and from the physical modeling environment, see Converting to and from Simulink Signals.

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Modeling an RF System

Specifying or Importing Component Data

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