A relaxed system is time-invariant, also known as fixed or stationary, if a time shift in prod?'ces the input signal causes a then time an shift input in x(tthe output to) produces signal. an Therefore, output if —an input In otherx(t)
an output y(tì, y(t to).
words no matter at what time an input is applied to a time-invariant relaxed SYStem, the svavetorm of the output is the same. We can also say that a (relaxed) system is time_ invariant if the. input by seconds merely delays the response by to seconds A relaxed discrete-time svs{em is said to be time-invariant if a shifted input x(k — ko) produces a shifted output -- In the case of discrete-time digital systems, we often use the tem ilžstead of time-invariant. The characteristics and parameters of a time4nvariant system do not change with time. A relaxed system that is not time-invariant is said to be time-varying.