Impulse response

When measuring a single input-single output linear system, such as a loudspeaker, the impulse response is defined as the output signal resulting from a short pulse input signal. The input signal pulse should theoretically be infinite short, this is called a Dirac pulse.

The impulse response completely describes a linear system, it is quite intuitive (e.g. a hand-clap in a room will give the impulse response of the room), and the phase and magnitude frequency response can be calculated from the impulse response. Because of this and because a MLS measurement gives the impulse response as the result, the data from a MLS measurement is saved in time domain as an impulse response.