Understanding Linear Time-Invariant Systems Linear time-invariant (LTI) systems combine the properties of linearity and time invariance. Linearity ensures adherence to superposition principles, satisfying both relativity and homogeneity laws, while time invariance reflects input delays in output. The system's behavior is characterized by its impulse response—output when an impulse signal is applied—and transfer function.
Defining LTI Systems Through Impulse Response and Transfer Function Impulse response defines LTI systems in the time domain but can be challenging to calculate directly from input-output relationships. Using Laplace or Fourier transforms simplifies this process by transitioning calculations into the frequency domain for deriving transfer functions like H(s). These tools are exclusive to LTI systems; non-LTIs lack defined impulse responses or transfer functions.