Abstract: A measuring device used for registering a test signal originating from a circuit structure applied to a wafer. The measuring device provides at least one test probe and at least one test transformer. The at least one test transformer is connected to the at least one test probe in an electrically conductive manner. In this context, the test transformer is arranged on the test probe.

Abstract: Second and third ports of a network analyzer are individually connected via cables to predetermined connection points on a differential transmission circuit on an object to be measured. A differential cable is connected to the differential transmission circuit. An antenna for receiving an electromagnetic wave radiated from the differential cable is connected to a first port of the network analyzer via a first cable. The network analyzer measures a three-port S parameter of the first, second, and third ports and calculates common-mode and normal-mode components of noise radiated from the differential cable. As a result, the source of noise in an electronic apparatus can be determined, and common-mode noise and normal-mode noise can be separately measured.

Abstract: An I/O port tester includes a first relay, a second relay, a first resistor, a second resistor, a plurality of serial plugs, a water sensor plug, a direct current (DC) voltage plug, and two data plugs. A half of the serial plugs is correspondingly connected to the other half of the serial plugs. The DC voltage plug is connected to the water sensor plug via a switch of the first relay and the first resistor, and connected to the water sensor plug via a switch of the second relay and the second resistor. The first and second resistors respectively simulate two different working conditions. The data plugs are respectively connected to an inductance coil of the first relay, and an inductance coil of the second relay.

Abstract: In order to reduce noise in telecommunications made over unshielded twisted pair (UTP) of metallic conductors an active electronic circuit for a two-to-four wire hybrid circuit reduces common mode signals without recourse to inductive components. The hybrid has a balance network that dynamically alters its impedance to closely balance with the two wire line impedance. Residual common mode signals are cancelled. Resistors are connected to the wires and the circuit generates a high impedance to differential mode signals and a virtual ground to common mode signals.

Abstract: A fully differential analogue circuit is tested by monitoring the currents in two branches when a common mode signal is applied and indicating correct operation if the two currents are correlated. A part of the circuit (T20,T21,S1,S2,S3,S4) is modified during test and currents through transistors (T20,T21) are monitored by means of a current mirror and current subtractor arrangement (T213,T214,T215,T216). A voltage (VRL) is produced that, with correlation of the currents, will be approximately mid way between the power supply rails and when mis-correlation occurs will tend to one of the supply rails. The voltage (VRL) is applied to a first amplifier (T219,T221) and to a second amplifier (T222,T223) having a different threshold value from the first amplifier. The outputs of the amplifiers will have opposite logic values if the voltage (VRL) lies between their threshold voltages and the EXOR gate 9 will give a logic 1 output indicating proper circuit function.

Abstract: A precision loop voltage measurement circuit outputs a voltage proportional to the differential voltage across a telephone wireline pair. This voltage is coupled to a tip-ring sense rectifier circuit having complementary transistor pairs coupled through a sense resistor to a node, which provides a current as of a composite of the tip-ring voltage and transistor voltage drops within the tip-ring sense rectifier circuit. A differential current extraction circuit generates a first current proportional to the sum of the tip-ring voltage plus voltage drops in the tip-ring sense rectifier circuit, and a second current fractionally proportional to only the internal voltage drops in the tip-ring sense rectifier circuit. The scaled currents are combined in an output resistor to produce a single ended output proportional to tip-ring voltage.

Abstract: A method for completely characterizing coupled transmission lines by short-pulse propagation is described. The complex frequency-dependent propagation matrix, impedance matrix and admittance matrix for a set of n parallel transmission lines can be determined by comparing the properties of two sets of coupled transmission lines of different length. Each transmission line set has two conductors of unequal length and ground conductors to form a coupled transmission line system. Each transmission line set can have uncoupled ends. An input pulse is provided at at least one node of each transmission line set. The complex frequency dependent propagation matrix of each transmission line set is determined by a comparison of the output pulses at the remaining nodes of each transmission line set which involves ratioing to cancel out the effect of the pad-to-probe discontinuity and the uncoupled ends which make it unnecessary to do any embedding.

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: An improved cable fault detection system which makes the fault detection independent of the ground shift between units coupled to the interface. This fault detection is based on differentially sensing the voltage on a wire pair, in a cable, and using the differential voltage applied to the wires to make a decision as to whether or not the cable is faulted. The disclosed differential sensing and fault checking scheme reviews both data states thus making the fault detection independent of the ground shift between machines on the interface and this is accomplished without reducing the load impedance presented to the cable by the differential receiver coupled thereto.

Abstract: Selectable mode rejection network (SMRN) for electromagnetic interference (EMI) excludes common mode (CM) and, alternatively, differential mode (DM) conducted emissions (CE) from entering power transmission lines from electrical equipment powered from such lines and producing such unwanted electrical noise. Phase-switching the SMRN determines whether CM or DM is so excluded, thereby facilitating measurement of the unexcluded type of CE. So used in measuring EMI, such SMRN enables improved filter design for the respective types of CE and composite filters for limiting both CM and DM CE.