Consider the linear constant coeficient difference equation:
y[n] -(1/4)y[n-1] = x[n].
Give an example of a (discrete-time) system whose output y[n] is related to the input x[n] by (for every possible input) and where the system is:
(a) causal, linear, and time-invariant. Determine the impulse response for the system and verify that an LTI system defined by the impulse response you determined satisfies the difference equation.
(b) noncausal, linear, and time-invariant. Determine the impulse response for the system and verify that an LTI system defined by the impulse response you determined satisfies the difference equation.