A square wave is a signal which oscillates between only two possible amplitude values. There is a function in Matlab for synthesizing a square wave which oscillates between 
[y] = square(2 * pi * f * t,duty)
Input Variables:
f – frequency of the signal (scalar in Hz)
t – an array of time samples for a signal.
duty – for duty cycle. The percentage of a cycle which is positive from [0,100].
Output Variable:
y – an array containing a square-wave signal.
Further documentation for the function is available here.
Now let’s look at another test signal called a sawtooth wave.