Editing Phase response (section)

{{Use American English|date = March 2019}}
{{Short description|Effect of filters or amplifiers on signals' phases as function of frequency}}
In [[signal processing]], '''phase response''' is the relationship between the [[phase (waves)|phase]] of a [[Sine wave|sinusoid]]al input and the output [[signal (information theory)|signal]] passing through any device that accepts input and produces an output signal, such as an [[amplifier]] or a [[filter (signal processing)|filter]].<ref name="JOS">{{cite web |last1=Smith |first1=J.O. |title=Introduction to Digital Filters with Audio Applications |url=http://ccrma.stanford.edu/~jos/filters/ |website=JOS |publisher=J.O. Smith |accessdate=1 February 2019 |ref=JOS}}</ref>

Amplifiers, filters, and other devices are often categorized by their amplitude and/or phase response. The amplitude response is the ratio of output amplitude to input, usually a function of the frequency. Similarly, phase response is the phase of the output with the input as reference. The input is defined as zero phase. A phase response is not limited to lying between 0° and 360°, as phase can accumulate to any amount of time.