%% Normalized and True z-plane Grid Lines on the Pole-Zero Map
% For this example, consider a discrete-time transfer function sys with a sample time of 0.1s. Now plot the pole-zero map of sys and visualize the default z-plane grid without specifying the sample time.

sys = tf([2 -3.4 1.5],[1 -1.6 0.8],0.1);
Ts = 0.1;
figure()
pzmap(sys)
zgrid()
axis equal

% Observe that the frequencies on the z-plane grid are normalized in terms of f\frac{\pi}{T}. To obtain the true frequency values on the grid, specify the sample time with the zgrid command.

figure()
pzmap(sys)
zgrid(Ts)
axis equal

% Now, observe that the frequency values on the plot are true values, that is, they are non-normalized.
% Copyright 2019 The MathWorks, Inc.