Abstract: A method and apparatus is provided for characterizing a differential circuit. A measurement system (200) is used to introduce input signals to the differential circuit and to measure corresponding output signals. Particularly, an input differential wave is introduced into the differential circuit (1010) while correspondingly measuring a differential output wave (1020) and a first common mode output wave (1030). Similarly, an input common mode wave is introduced (1040) while measuring a second differential output wave (1050) and a second common mode output wave (1060).

Abstract: A current mode data communication system is disclosed in which the system data bus is formed by an unshielded twisted wire pair (12). Coupled to the data bus by bus couplers (16) and bus-to-stub couplers (80) are current mode data stubs (82), which also are formed by pairs of twisted, unshielded wires (84 and 86). One or more interface-to-stub couplers (88) are inductively coupled to each curretn mode data stub and, in addition, are connected in signal communication with one of the system utilization devices (10). Data signals propagating along the system data bus (12) are coupled to each utilization device (10) via an associated bus coupler (16), bus-to-stub coupler (80), and interface-to-stub coupler (88) without reflecting the signal into the system data bus (12).