Editing Balanced line (section)

== Baluns ==
{{Main|Balun}}
Interfacing balanced and unbalanced lines requires a [[balun]]. For example, baluns can be used to send [[line level]] audio or [[E-carrier level 1]] signals over coaxial cable (which is unbalanced) through {{convert|300|ft|m}} of balanced [[category 5 cable]] by using a pair of baluns at each end of the CAT5 run. As the signal travels through the balanced line, noise is induced and added to the signal. As the CAT5 line is carefully impedance balanced, the noise induces equal (common-mode) voltages in both conductors. At the receiving end, the balun responds only to the difference in voltage between the two conductors, thus rejecting the noise picked up along the way and leaving the original signal intact.

A once common application of a [[radio frequency]] balun was found at the antenna terminals of a [[television]] receiver. Typically a 300-ohm balanced [[twin lead]] antenna input could only be connected to a coaxial cable from a cable TV system through a balun.