Issue with doing FM on SIMULINK

Hello, I want to run the following Model, but it keeps giving me that error how can I fix it please?

Secondly, I want to replace that Message 1 Box, with the following input from my code, how can I do this?

fs=1000;

t = 0:1/fs:2;

% Defining the messages signal m(t)

message =@(t) -sawtooth(2*pi*(t+0.5)) ;

Thank you

Answer 1

[Jim Riggs]

1) The error is generated because the integration block is a continuous block, and you have specified a discrete solver.

Change the solver type to "Auto" in the model settings.

2) You can code the function that you want using a "MATLAB Function" block (found under the user-defined functions tab).

Assuming that variable "t" is time in your function, you will have to supply t as an input;

Inside the MATLAB function block you provide the following code:

function y = fcn(t) 
y = -sawtooth(2*pi*(t+0.5));

You can control the signal by setting the parameters for the solver. For example, set the solver to "fixed time step" and specify a time step of .001. Set the simulation stop time to 2. This will create a sawtooth signal from 0 to 2 with a 0.001 step size.