Actually arrie, a differential pair is a pair that always agrees but in their own way as to what 'ground' is =) Sum or difference doesn't mater you always end up after an absolute conversion with the same result less any common mode loss. Design is in the particulars of a given relational situation.
Actually arrie, a differential pair is a pair that always agrees but in their own way as to what 'ground' is =) Sum or difference doesn't mater you always end up after an absolute conversion with the same result less any common mode loss. Design is in the particulars of a given relational situation.
What Sceadwian is trying to say is that differential pair uses a pair of wires, usually twisted and each signal is seperated from the other by a few volts depending on the standard (+/- 1.5V for RS-485 for example). The basic idea is that noise or transients that are induced on one wire also gets induced on the other. Whether the signal spikes high or low doesn't matter, the voltage seperation is the same between the pair. It's best not to think in terms of "what ground is" but in terms of a voltage with respect to the other wire. A quick google search will yield tons of information on this subject.