A common-impedance ground path in a measurement circuit is present when a number of different circuit elements or instrument are connected to ground through the same conductor. This will cause (conductively coupled interference) in the sytem components connected to the common-ground path. The problem can become significant if the path possesses a substantial impedance to earth ground. As an example, consider the case where an analog-signal ground and digital-ground are both connected to the same earth-grounded conductor. This conductor then acts as an impedance that is common to both the analog and the digital ground paths. If the impedance of the earth-grounded conductor is substantial, it is highly likely that switching transients from the digital logic circuits will be coupled to the wire carrying the analog signals.