When I run my code, I keep getting this error: Unable to convert expression into double array."

clear all

close all

syms z w

Gz=z/(z-1);

Gjw=subs(Gz,z,exp(j*w));

figure(1)

subplot(2,1,1)

stem(real(Gjw))

xlabel('frec (Hz)')

ylabel('MÓDULO')

stem(imag(Gjw)) %grafica la parte imag

subplot(2,1,2)

xlabel('frec (Hz)')

ylabel('ARGUMENTO')

sgtitle('G(jw)')

Answer 1

[Benjamin Thompson]

You should use i for the imaginary number, instead of j. In your subs command you have not defined what w is.

>> Gjw

Gjw =

exp(w*1i)/(exp(w*1i) - 1)

>> Gjw=subs(Gz,z,exp(i*w));

>> Gjw=subs(w, 2);

>> stem(real(Gjw))

Now there should be no error