The impulse response of a system is the output of the system in response to a unit impulse input signal. This lesson introduces you convolution, which expresses the output of an LTI system as a function of its input and impulse response. You will learn how the impulse response reveals whether the system is causal and finite or infinite impulse response. The finite and infinite impulse response properties depend on whether the difference equation description for the system indicates that the output depends only on the input, or also on past values of the output.
The impulse response description for a system is a useful tool for both computing the output of a system from its input and for analysis of system behavior.