Editing Transfer function (section)

=== Discrete-time ===
{{See also|Z-transform#Linear constant-coefficient difference equation}}
[[Discrete-time]] signals may be notated as arrays indexed by an [[integer]] <math>n</math> (e.g. <math>x[n]</math> for input and <math>y[n]</math> for output). Instead of using the Laplace transform (which is better for continuous-time signals), discrete-time signals are dealt with using the [[z-transform]] (notated with a corresponding capital letter, like <math>X(z)</math> and <math>Y(z)</math>), so a discrete-time system's transfer function can be written as:

<math display="block">H(z) = \frac{Y(z)}{X(z)} = \frac{\mathcal{Z}\{y[n]\}}{\mathcal{Z}\{x[n]\}}.</math>