Specify the Circuit Envelope Simulation Environment

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Access Circuit Envelope Libraries Ground the RF System Configure the SimRF Environment Simulate the SimRF Environment

This section of the tutorial shows you how to:

• Use a Solver Configuration block to provide local solver settings to the SimRF environment

• Use a SimRF Parameters block to define the carriers and global noise behavior in the SimRF environment.

• Use a Ground block to reference a model to electrical ground.

The Solver Configuration and Ground block are the bare minimum that SimRF software requires in order to perform circuit-envelope simulation. Models that are missing one of these two blocks do not run. In order to simulate the SimRF environment at carrier frequencies other than 0 Hz, a model must also contain a SimRF Parameters block.

To begin, open a new model by selecting File > New > Model.

Access Circuit Envelope Libraries

Open the SimRF library by clicking the Start button and selecting Simulink > SimRF > Block Library (Circuit Envelope), or type

simrflib

at the MATLAB Command Window prompt.

The SimRF library contains three sublibraries:

• The Circuit Envelope library contains blocks for circuit-envelope simulation. This manual often refers to the Circuit Envelope library as the SimRF library. The SimRF Getting Started Guide and SimRF User's Guide pertain exclusively to this library.

• The Equivalent Baseband and Idealized Baseband library contain blocks for equivalent-baseband simulation. Refer to the Equivalent Baseband section of the SimRF documentation for more information on using these blocks.

To continue, double-click the Circuit Envelope library.

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Ground the RF System

Place a Ground block in your model:

1. In the SimRF library, double-click Elements to open the SimRF Elements library.

2. Drag and drop a Ground block onto your model. In the library, the block is abbreviated 'Gnd'.

Connecting SimRF models to ground provides an electrical reference for the system, from which node voltages are defined. A SimRF model is grounded if:

• The model contains a Ground block that connects to the SimRF Environment, or

• The model contains an Amplifier, Continuous Wave, Mixer, Noise, Sinusoid, or S-Parameters block that is internally grounded. To internally ground one of these blocks, select the Ground and hide negative terminals check box in the block dialog box.

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Configure the SimRF Environment

To continue the tutorial:

1. Place a Solver Configuration block in your model. In the SimRF library, double-click Utilities to open the SimRF Utilities library, then drag and drop a Solver Configuration block onto your model.

2. Place a SimRF Parameters block in your model. If the SimRF Utilities library is not already open, double-click Utilities to open it, then drag and drop a SimRF Parameters block onto your model.

3. Connect the Ground, Solver Configuration, and SimRF Parameters blocks to each other. The following figure shows one possible configuration.

   

A model can contain multiple Solver Configuration and SimRF Parameters if all of the following conditions are met:

• Each Solver Configuration and SimRF Parameters block connects to a separate SimRF environment.

• No two Solver Configuration or SimRF Parameters blocks connect to the same environment.

• The separate SimRF environments are isolated from each other in separate subsystems.

  Warning   Simulating more than one SimRF environment without using subsystems is not supported.

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Simulate the SimRF Environment

To run the model, select Simulation > Start.

The model simulates according to the default settings of the Solver Configuration and SimRF Parameters blocks and produces no output:

• In the SimRF Parameters block dialog, the Carrier frequencies parameter specifies a carrier of 0 Hz in the system. In the next section, Model an RF Mixer, you specify additional carriers for circuit-envelope simulation.

• In the Solver Configuration block dialog, the Use local solver check box is cleared, so the model uses the specified global solver. The examples in the SimRF User's Guide show you how to configure the SimRF environment to use a local solver.

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Frequency Conversion

Model an RF Mixer

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