Differential signalling

Differential signalling is a method for <a href="/facts/Electrically/hNC8D65W">electrically</a> transmitting <a href="/facts/Information/3LdrzXtJ">information</a> using two complementary <a href="/facts/Signal/41YqUJ8c">signals</a>. The technique sends the same electrical signal as a differential pair of signals, each in its own <a href="/facts/Electrical_conductor/BSuyupLP">conductor</a>. The pair of conductors can be wires in a <a href="/facts/Twisted-pair/L426Jk2C">twisted-pair</a> or <a href="/facts/Ribbon_cable/edXPXe9U">ribbon cable</a> or traces on a <a href="/facts/Printed_circuit_board/muSR2p43">printed circuit board</a>. 
Electrically, the two conductors carry <a href="/facts/Voltage/EN2po6N2">voltage</a> signals which are equal in <a href="/facts/Absolute_value/dwJBpEs5">magnitude</a>, but of opposite <a href="/facts/Electrical_polarity/fGRB4SGP">polarity</a>. The receiving circuit responds to the difference between the two signals, which results in a signal with a magnitude twice as large.
The <a href="/facts/Symmetrical/hpu7DK8p">symmetrical</a> signals of differential signalling may be referred to as balanced, but this term is more appropriately applied to <a href="/facts/Balanced_circuit/sMCd065d">balanced circuits</a> and <a href="/facts/Balanced_line/XubfIRdc">balanced lines</a> which reject <a href="/facts/Common-mode_interference/8GCxkDAb">common-mode interference</a> when fed into a differential receiver. Differential signalling does not make a line balanced, nor does <a href="/facts/Noise_(electronics)/Izbv38Rr">noise</a> rejection in balanced circuits require differential signalling. 
Differential signalling is to be contrasted to <a href="/facts/Single-ended_signalling/u1FAC18z">single-ended signalling</a> which drives only one conductor with signal, while the other is connected to a fixed reference voltage.

Differential signalling open-in-new

Differential signalling