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    %% Falltime, Reference-Level Instants, and Reference Levels
% Determine the fall time, reference-level instants, and reference levels
% in a 2.3 V clock waveform sampled at 4 MHz.

% Copyright 2015 The MathWorks, Inc.


%%
% Load the 2.3 V clock waveform along with the sampling instants.

load('negtransitionex.mat','x','t')

%%
% Determine the fall time, reference-level instants, and reference levels.

[f,lt,ut,ll,ul] = falltime(x,t);

%%
% Plot the waveform with the upper and lower reference levels and reference
% level instants. Show that the fall time is the difference between the
% lower- and upper-reference level instants.

plot(t,x)

xlabel('seconds')
ylabel('Volts')

hold on
plot([lt ut],[ll ul],'ro')
hold off

fprintf('Rise time is %g seconds.',lt-ut)