A MATLAB script that defines a function in terms of the basic unit step.

Unit_Step_Function.m

%% FUNDAMENTAL UNIT STEP FUNCTION %%

%Subplot dimensions%
Rows = 3;
Columns = 1;

u = @(n) (n >= 0);
subplot(Rows,Columns,1); fplot(u);
title("Unit Step Function");
xlim([-5 5]);
ylim([-0.1 1.1]);

%% FUNCTION CHARACTERIZED IN TERMS OF UNIT STEPS %%

Function = @(n) u(n) - u(n-4);
subplot(Rows,Columns,2); fplot(Function);
title("Function Characterized in Terms of Unit Steps");
xlim([-5 5]);
ylim([-0.1 1.1]);

%% DISCRETE PLOT OF ABOVE FUNCTION %%

N = (0:5);
subplot(Rows,Columns,3); stem(Function(N));
title("Discrete Plot of Above Function");
xlim([-5 5]);
ylim([-0.1 1.1]);

Output Result