Helping with the plot of a function

Hello!! I am trying to plot a function in freq-domain that decrease with f, I should get a kind of sin that decrease when time goes by, but I am not getting it. This is the code Tc=1*10^-3;

f=linspace(0,10000000);

R=zeros(size(f));

for a=1:1:100

R(f)=i*Tc*sinc(a(f)*Tc/2)*sin(pi*a(f)*Tc/2);

end

plot(f,R(f))

Please, someone could help.

Thanks in advance, Nicolas

Answer 1

[Jan]

• Is the multiplication by i intented?
• What is Tc?
• a is the scalar loop counter, therefore a(f) should fail.
• You assign R(f) in the loop, but this does not depend on the loop counter a.

[Nicolas]

Hello Jam!

i is the imaginatary unit and I want to multiply by it, then Tc is just a period that I defined before. I saw what you mean and now I modified my code but, now I can get the plot buut nothing is on it

Tc=1*10^-3;

f=linspace(0.1,2e6);

for aux=1:1:100;

R(aux)=i*Tc*sinc(f(aux).*Tc/2)*sin(pi*f(aux).*Tc/2);

end

plot(f,R(aux))

thanks, I dont know where is the problem

[Nicolas]

In fact, when I check in the workspace it appear that aux is a single value = 100, not a vector....

[Jan]

Yes, aux is a scalar. This is the expected and wanted behaviour of a FOR-loop. Try this:

for i = 1:10; disp(i); x(i) = i*i; end, disp(x)

For your problem: "plot(f, R)" will use all elements of R.