Plot time continous singal by using a sum of time invariant signals

I want to make a plot of the following:

Where the input x(t) is given as:

and x[n] is the sampled signal of x(t). Below is the code of how I tried to solve it:

f_s = 2,1; Ts = 1/f_s;

t = -5:Ts:5; x = @(t)((3/2) + (3/10) sin(2pit) + sin(2pit/3) - sin(2pit/10)).sinc(t);

syms n

x_t = @(t) symsum(x(n/f_s)sinc((t-nTs)/Ts), n, -5, 5);

x_0 = x_t(t);

plot(x_0, t)

But I can't seem to make it work nor do I understand why. Below are error messages:

Error using symengin Division by zero.

Error in sym/symsum (line 70) rSym = mupadmex('symobj::map',fsym.s,'symobj::symsum',x.s,a.s,b.s);

Error in matlabasklol>@(t)symsum(x(n/f_s)sinc((t-nTs)/Ts),n,-5,5) (line 7) x_t = @(t) symsum(x(n/f_s)sinc((t-nTs)/Ts), n, -5, 5);

Error in matlabasklol (line 8) x_0 = x_t(t);

Would be very grateful for some help or pointers here, many thanks.

Answer 1

[Chandra]

Hi,

Replace the “symsum” function with “for” loop and plot the signal

f_s = 2;  

Ts = 1/f_s;  

t = -5:Ts:5; % change the the interval of signal like -10:Ts/5:10 

x = @(t)((3/2) + (3/10)*sin(2*pi*t) + sin(2*(pi)*t/3) - sin(2*pi*t/10)).*sinc(t); 

x_0 = zeros(1,length(t)); 

for j = 1:length(t) 

    for i = -6:6 

        a = x(i)*sinc((j-i*Ts)/Ts); 

        x_0(j) = a + x_0(j); 
    end 
end 

plot(t,x_0) 

Refer the below link for further reference about using the sin in degrees and radians

https://www.mathworks.com/help/matlab/ref/sind.html