how to simulate communication channel in control toolbox

Is there a way to simulate a communication channel in a simulink like the one shown below, using some block like the BSC or the AWGN channel, in order to simulate an error produced directly by the communication channel being used. I need it to be an element that can be easily incorporated, since it is to perform simulation activities in a classroom.

Thanks

[Paul]

Hi Juan,

Can you be more specific? What precisely do you want to change in that Simulink model? Perhaps you're looking for a different source to replace the Step or Pulse Generator blocks?

[Juan José Aguirre Ocampo]

I want to simulate a communication channel as seen in this control loop, the BSC is an example of what I want to implement but for this specific case I do not know how to make the information digitized so that it can be transmitted (If I run this program generates error immediately), I do not know what other block could be used to simulate this feature or if it is strictly necessary to perform a modulation to make correct use of the communication channels.

Answer 1

[Swastik]

Hi @Juan José Aguirre Ocampo,

 I recreated the model based on the image you provided in the comments, and I faced the same issue:

https://www.mathworks.com/matlabcentral/answers/2117591-how-to-simulate-communication-channel-in-control-toolbox#comment_3160266

I also faced the error while simulating this model, to be specific, the error I faced was:

Error: Unable to determine signal dimensions. There is a loop consisting of 'model/PID Controller/Sum/Sum_PID/Sum' that cannot be resolved because signal dimensions are defined by a cyclic relationship. Specifying the signal dimensions on Inport, Mux, Selector, Demuxes will help resolve signal dimensions in the loop.  You can also use the Signal Specifications to define the signal dimensions. 

I believe that you are facing the same error. The error you encountered is common when dealing with algebraic loops in Simulink models, particularly when signal dimensions cannot be determined due to cyclic relationships.

One approach to resolve this issue is to remove the algebraic loop and introduce an additional source. This modification allows the simulation to proceed without errors:

If you prefer to keep the algebraic loop, you can resolve the issue by explicitly specifying the signal dimensions using a "Signal Specification" block. In this case, you can set the dimensions to [1 1].

I hope this solution helps.