How to plot frequency response at discrete time?

I want to plot a frequency response ( z-transform)

How can I plot this graph?

Before asking to you, I tried to solve it by myself with the following code, but failed.

for example) H(z) = 1 + 0.5 exp(j*pi/4) * z^-1 ( H(e^jw) = 1+0.5exp(j*(pi/4-w)) )

>> t = linspace(-pi,pi);

>> x = 1+0.5*exp(j*(pi/4-t));

>> figure(1); plot(t,real(x)); grid on;

Answer 1

[Mahesh Taparia]

Hi

You can use freqz function to plot frequency response at discrete time. You can refer this example to plot the response of your filter.

Hope it will help!