Artificial transmission line

File:Artificial Telephone Line 6000ft, 24 gauge, Schematic.png

In telecommunications, an artificial transmission line is a two-port electrical network that has the characteristic impedance, transmission time delay, phase shift, or other parameter(s) of a real transmission line. It can be used to simulate a real transmission line in one or more of these respects.Federal Standard 1037C

Early artificial lines were used in telephony research and took the form of a cascade of lattice phase equalisers to provide the necessary delay. The lattice phase circuit was invented by Otto Zobel in the 1920s.Zobel, O J, Phase-shifting network, [https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US1792523.pdf US patent 1 792 523], filed 12 March 1927, issued 17 Feb 1931.Zobel, O J, [https://archive.org/stream/bellsystemtechni02amerrich#page/n27/mode/2up "Theory and design of uniform and composite electric wave filters"], Bell System Technical Journal, vol. 2 (1923), pp. 1–46.