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    %% Nichols Response with Nichols Grid Lines
% Plot the Nichols response with Nichols grid lines for the following
% system:
%%
% 
% $$H(s) = \frac{{ - 4{s^4} + 48{s^3} - 18{s^2} + 250s + 600}}{{{s^4} +
% 30{s^3} + 282{s^2} + 525s + 60}}.$$
% 
%%

% Copyright 2015 The MathWorks, Inc.

H = tf([-4 48 -18 250 600],[1 30 282 525 60]);
nichols(H)
ngrid
%%
% The right-click menu for Nichols charts includes the *Tight* option under *Zoom*.
% You can use this to clip unbounded branches of the Nichols chart.