Common-mode signal: Difference between revisions

Revision as of 17:03, 7 June 2023

Revision as of 17:10, 7 June 2023

Line 14:

==Methods of eliminating common-mode signals==

* [[Differential amplifier]]s or receivers that respond only to voltage differences, e.g. those between the wires that constitute a pair. This method is particularly suited for [[instrumentation]] where signals are transmitted through DC bias. For [[Sensor|sensors]] with very high [[output impedance]] that require very high [[common-mode rejection ratio]], a differential amplifier is combined with input [[Buffer amplifier|buffers]] to form an [[instrumentation amplifier]].

* An inductor where a pair of signallingsignaling wires follow the same path through the inductor, e.g. in a [[bifilar winding]] configuration such as used in Ethernet magnetics.<ref>{{Cite web |url=http://pulseeng.com/products/datasheets/H325.pdf |title=Archived copy |access-date=2013-12-17 |archive-date=2016-03-04 |archive-url=https://web.archive.org/web/20160304000938/http://pulseeng.com/products/datasheets/H325.pdf |url-status=dead }}</ref> Useful for AC and DC signals, but will filter only higher frequency common-mode signals.

* A [[transformer]], which is useful for AC signals only, and will filter any form of common-mode noise, but may be used in combination with a bifilar wound coil to eliminate [[capacitive coupling]] of higher frequency common-mode signals across the transformer. Used in twisted pair Ethernet.<ref>{{Cite web |url=http://pulseeng.com/products/datasheets/H325.pdf |title=Archived copy |access-date=2013-12-17 |archive-date=2016-03-04 |archive-url=https://web.archive.org/web/20160304000938/http://pulseeng.com/products/datasheets/H325.pdf |url-status=dead }}</ref>