Use Simulink time variable in a Matlab Function

Hello everybody,

I want to implement a Matlab function into my Simulink Model, where I upconvert a signal to 24 GHz. I therefore want to implement the function y = real(u*exp(i*2*pi*24e9*t) as a Matlab function, where u is a complex time signal which is created in Simulink and t stands for the time in Simulink. I now somehow need to get the variable t of my Simulink project into my Matlab function in order to calculate the given function, but I dont know how to implement the variable t.

Thanks in advance for helping.

Answer 1

[Ameer Hamza]

You can directly create MATLAB function inside Simulink using MATLAB function block: https://www.mathworks.com/help/simulink/ug/creating-an-example-model-that-uses-a-matlab-function-block.html. To feed the simulation time, use the clock block: https://www.mathworks.com/help/simulink/slref/clock.html.

[Thomas Schütz]

Thanks a lot. I didn't know that it is possible to use the clock block for the simulation time.

[Ameer Hamza]

I am glad to be of help!

[Matthew Mishrikey]

I tried to do something like your suggestion using a function block, but Matlab says it contains a block that updates persistent or state variables while computing outputs and is not supported in an algebraic loop.

function switch_control = current_monitor(current, clock)
persistent starttime;
persistent tripped;

if isempty(starttime)
    starttime = 0;
end

if isempty(tripped)
    tripped = false;
end


if (current > 10)
    starttime = clock;
    
    if ((clock - starttime) > 0.2)
        tripped = true;
    end
end

if(tripped)
    switch_control = 0;
else
    switch_control = 1;
end

end