Editing Chirp (section)

== Relation to an impulse signal ==

[[File:Chirp animation.gif|thumb|Chirp and impulse signals and their (selected) [[spectral component]]s. On the bottom given four [[monochromatic]] components, sine waves of different frequency. The red line in the waves give the relative [[phase shift]] to the other sine waves, originating from the chirp characteristic. The animation removes the phase shift step by step (like with [[matched filter]]ing), resulting in a [[Sinc function|sinc pulse]] when no relative phase shift is left.]]
A chirp signal shares the same spectral content with an [[Dirac delta function|impulse signal]]. However, unlike in the impulse signal, spectral components of the chirp signal have different phases,<ref name="berkeley">{{cite web | url=http://setiathome.berkeley.edu/ap_chirp.php|title=Chirped pulses|publisher=setiathome.berkeley.edu|access-date=2014-12-03}}</ref><ref>{{cite book |last1=Easton Jr |first1=Roger L. |title=Fourier Methods in Imaging |date=2010 |publisher=John Wiley & Sons |isbn=978-1-119-99186-1 |page=700 }}</ref><ref name="dspguide">{{cite web|url=http://www.dspguide.com/ch11/6.htm|title=Chirp Signals | publisher=dspguide.com | access-date=2014-12-03}}</ref><ref name=arxiv>{{cite arXiv | eprint=1907.04186 | last1=Nikitin | first1=Alexei V. | last2=Davidchack | first2=Ruslan L. | title=Bandwidth is Not Enough: "Hidden" Outlier Noise and Its Mitigation | year=2019 | class=eess.SP }}</ref> i.e., their power spectra are alike but the [[phase spectrum|phase spectra]] are distinct. [[Dispersion (optics)|Dispersion]] of a signal propagation medium may result in unintentional conversion of impulse signals into chirps ([[Whistler_(radio)|Whistler]]). On the other hand, many practical applications, such as [[Chirped pulse amplification|chirped pulse amplifiers]] or echolocation systems,<ref name="dspguide"/> use chirp signals instead of impulses because of their inherently lower [[Crest factor|peak-to-average power ratio]] (PAPR).<ref name=arxiv/>