Editing Frequency-change signaling (section)

In [[telecommunications]], '''frequency-change signaling''' is a  [[telegraph]] [[Signaling (telecommunications)|signaling]] method in which one or more particular [[frequency|frequencies]] correspond to each desired signaling condition of a telegraph [[code]].  The transition from one set of frequencies to the other may be a continuous or a discontinuous change in the [[frequency]] or [[phase (waves)|phase]].<ref>{{cite book | title = Modern Dictionary of Electronics | author = Rudolf F. Graf | publisher = Newnes | year = 1999 | isbn = 0-7506-9866-7 | url = https://books.google.com/books?id=uah1PkxWeKYC&q=%22Frequency-change+signaling%22&pg=PA304 }}</ref>