1, time-invariant system, also known as time-invariant system, is characterized by its own properties that do not change with time. Specifically, the response behavior of the system depends only on the behavior of the input signal and the characteristics of the system, and has nothing to do with the time when the input signal is applied. That is, if the input u(t) produces the output y(t), it will act on the system after the input delay τ, and the output produced by u(t-τ) is y(t-τ).

2. Time-varying system, in which one or more parameter values change with time, so that the whole characteristic also changes with time.

For linear continuous systems, when one or more parameters in the system change with time (that is, as a function of time), its mathematical model is a linear differential equation with variable coefficients. For linear discrete systems, when one or more parameters in the system change with time (that is, the function of time), its mathematical model is a linear difference equation with variable coefficients.

Extended data:

According to the characteristics of the system, the system can be divided into the following categories:

1, linear system and nonlinear system

2. Stable (time-invariant) systems and time-varying systems

3. Continuous time systems and discrete time systems

4. Causal system and non-causal system

The system can be divided into lumped parameter system and distributed parameter system according to whether its parameters are lumped or distributed. According to whether the system contains source or not, it can be divided into passive system and active system. According to whether the system contains memory elements, it can be divided into real-time system and dynamic system.

Baidu Encyclopedia-Constant System

Baidu Encyclopedia-Time-varying System