Chakravorty, Pragnan (2018). «What Is a Signal? [Lecture Notes]». IEEE Signal Processing Magazine. 35 (5): 175–177. Bibcode:2018ISPM...35e.175C. doi:10.1109/MSP.2018.2832195. «Consequently, a signal, represented as a function of one or more variables, may be defined as an observable change in a quantifiable entity.»
Roland Priemer (1991). Introductory Signal Processing. World Scientific. s.1. ISBN978-9971509194. Arkivert fra originalen 2. juni 2013. «A signal is a function that conveys information about the behavior of a system or attributes of some phenomenon.»
Chakravorty, Pragnan (2018). «What Is a Signal? [Lecture Notes]». IEEE Signal Processing Magazine. 35 (5): 175–177. Bibcode:2018ISPM...35e.175C. doi:10.1109/MSP.2018.2832195. «Consequently, a signal, represented as a function of one or more variables, may be defined as an observable change in a quantifiable entity.»
Roland Priemer (1991). Introductory Signal Processing. World Scientific. s.1. ISBN978-9971509194. Arkivert fra originalen 2. juni 2013. «A signal is a function that conveys information about the behavior of a system or attributes of some phenomenon.»