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Verify Viterbi Decoder Using ModelSim

This example shows how to use HDL Verifier™ in conjunction with ModelSim® to verify HDL code for a fixed-point Viterbi decoder.

1. Open the Simulink Model

Open the model viterbi_modelsim.mdl.

2. Launch ModelSim

Before launching ModelSim, make sure that the ModelSim executables are on the MATLAB® system path.

Launch ModelSim by double-clicking the "ModelSim Startup Command" block in the Simulink model, or by executing the following command in your MATLAB console:

vsim('tclstart',viterbi_tclcmds_modelsim('vsimulink'));

3. Run Simulation

When ModelSim has finished compiling the VHDL files and loading the simulation, the text "Ready for cosimulation ..." is displayed in the ModelSim command window. After you see this text, start Simulink simulation from the open model.

When the simulation stops, observe the bit error rate displayed at the "BER Display" block.

4. Rerun Simulation with Different Parameters.

There are two parameters that control the behavior of this model. The first is the frame size and the other is the Es/No used for simulation. You can change those parameters in the MATLAB console. For example,

FrameSize = 10;
EsNo      = 5;

Then you can rerun the cosimulation with updated parameters by starting the simulation again from the model.

4. Finish Simulation

Close the ModelSim session. Then return to Simulink and close the model.

close_system('viterbi_modelsim');
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