| Getting Started | |
Setting Block Parameters
You can control the way a Simulink block functions by setting its parameters. To view or change a block's parameters, double-click the block. This opens a dialog box called the block's mask. For example, the mask for the Phase Noise block is shown in the following figure.
Mask for the Phase Noise Block
To change the amount of phase noise, click in the Phase noise level (dBc/Hz) field and enter a new value. Then click OK.
Alternatively, you can enter a variable name, such as phasenoise, in the field. You can then set a value for that variable at the MATLAB prompt in the Command Window, for example by typing phasenoise=2. Setting parameters at the command line is convenient if you need to run multiple simulations with different parameter values. See the section Running Multiple Simulations.
You can also change the amount of noise in the AWGN Channel block. Double-click the block to bring up its mask, and change the value in the Es/No parameter field. This changes the signal to noise ratio, in decibels. Decreasing the value of Es/No increases the noise level.
You can experiment with the model by changing these or other parameters and then running a simulation. For example,
0 in the mask for the Phase Noise block.
100 in the mask for the AWGN Channel block.
This essentially removes all noise from the model. When you now run a simulation, the scatter plot appears as in the figure Constellation for 256-ary QAM.
| | Displaying the Error Rate | Displaying a Plot of Phase Noise | |