Editing Analog signal processing (section)

===Impulse===
An impulse ([[Dirac delta function]]) is defined as a signal that has an infinite magnitude and an infinitesimally narrow width with an area under it of one, centered at zero.  An impulse can be represented as an infinite sum of sinusoids that includes all possible frequencies.  It is not, in reality, possible to generate such a signal, but it can be sufficiently approximated with a large amplitude, narrow pulse, to produce the theoretical impulse response in a network to a high degree of accuracy.  The symbol for an impulse is δ(t).  If an impulse is used as an input to a system, the output is known as the impulse response.  The impulse response defines the system because all possible frequencies are represented in the input