Memoryless Systems
A system is said to be memoryless if for any input, t=a, the output of the system only depends on the given input, t=a.
Example:
$ y(t)=2*x(t) $
Systems with Memory
A system is said to have memory if for any input, t=a, the output of the system depends on an input other than t=a and any combination of t.
Example:
$ y(t)=x(t)+x(t-1) $
