Editing Signal processing (section)

===Continuous time===
[[Continuous signal|Continuous-time signal]] processing is for signals that vary with the change of continuous domain (without considering some individual interrupted points).

The methods of signal processing include [[time domain]], [[frequency domain]], and [[complex frequency|complex frequency domain]]. This technology mainly discusses the modeling of a [[linear time-invariant]] continuous system, integral of the system's zero-state response, setting up system function and the continuous time filtering of deterministic signals. For example, in time domain, a continuous-time signal <math>x(t)</math> passing through a [[linear time-invariant]] filter/system denoted as <math>h(t)</math>, can be expressed at the output as

<math>
y(t) = \int_{-\infty}^\infty h(\tau) x(t - \tau) \, d\tau
</math>

In some contexts, <math>h(t)</math> is referred to as the impulse response of the system. The above [[convolution]] operation is conducted between the input and the system.