Editing Ground loop (electricity) (section)

=== Balanced interconnection ===
Balanced connections see the spurious noise due to ground loop current as [[common-mode interference]] while the signal is [[differential signaling|differential]], enabling them to be separated at the destination by circuits having a high [[common-mode rejection ratio]]. This rejection can be accomplished with transformers or semiconductor output drivers and line receivers.

With the increasing trend towards digital processing and transmission of audio signals, the full range of isolation by small pulse transformers, optocouplers or fiber optics become more useful. Standard protocols such as [[S/PDIF]], [[AES3]] or [[TOSLINK]] are available in relatively inexpensive equipment and allow full isolation, so ground loops need not arise, especially when connecting between audio systems and computers.

In [[instrumentation]] systems, the use of differential inputs with high common-mode rejection ratio, to minimize the effects of induced AC signals on the parameter to be measured, is widespread. It may also be possible to introduce narrow [[Band-stop filter|notch filters]] at the power frequency and its lower [[Harmonics (electrical power)|harmonics]]; however, this can not be done in audio systems due to the objectionable audible effects on the wanted signal.