'''[[Digital object identifier|Digital]] signal processing''' ('''DSP''') is the use of [[digital processing]], such as by computers or more specialized [[digital signal processor]]s, to perform a wide variety of [[signal processing]] operations. The [[digital signal]]s processed in this manner are a sequence of numbers that represent [[Sampling (signal processing)|samples]] of a [[continuous variable]] in a ___domain such as time, space, or frequency. In [[digital electronics]], a digital signal is represented as a [[pulse train]],<ref>{{cite book |author=B. SOMANATHAN NAIR |title=Digital electronics and logic design |date=2002 |isbn=9788120319561 |publisher=PHI Learning Pvt. Ltd. |quote=Digital signals are fixed-width pulses, which occupy only one of two levels of amplitude. |page=289}}</ref><ref>{{cite book |author=Joseph Migga Kizza |isbn=9780387204734 |date=2005 |publisher=Springer Science & Business Media |title=Computer Network Security}}</ref> which is typically generated by the switching of a [[transistor]].<ref>{{cite book |title=2000 Solved Problems in Digital Electronics |date=2005 |publisher=[[Tata McGraw-Hill Education]] |isbn=978-0-07-058831-8 |page=151 |url=https://books.google.com/books?id=N6FDii6_nSEC&pg=PA151}}</ref>
Digital signal processing and [[analog signal processing]] are subfields of signal processing. DSP applications include [[Audio signal processing|audio]] and [[speech processing]], [[sonar]], [[radar]] and other [[sensor array]] processing, [[spectral density estimation]], [[statistical signal processing]], [[digital image processing]], [[data compression]], [[video coding]], [[audio coding]], [[image compression]], signal processing for [[telecommunications]], [[control system]]s, [[biomedical engineering]], and [[seismology]], among others.
