Abstract: A method is provided, the method comprising associating each net of traces in a list of nets of the traces on a routed PCB with a parallelism index value and sorting the list of the nets of the traces on the routed PCB based on the parallelism index values. The method also comprises providing a list of victim nets of traces on the routed PCB based on the parallelism index values, each of the victim nets on the list of the victim nets associated with at least one offending net of traces on the routed PCB.

Abstract: The present invention provides methods for using time domain analysis of NEXT, Return Loss and the like, in conjunction with the application of time or distance referenced limits to verify and determine compliance of the performance requirements of connections in a typical link. Time domain analysis of NEXT, Return Loss data and the like, suitably provides the performance characteristics of a link as a function of time or distance. When coupled with time or distance performance curves for connections, it can be determined if the transmission fault is at a connection or in the cable. The time limit curves for connections can be generated based on the frequency domain performance requirements for connecting hardware of a specific level of performance. The connection time limit curves thus provide an interpretation means to determine if the connection is within performance standards, allowing improved isolation of the fault condition.

Abstract: A data transmission system for external use with a controller area network is installed on a motor vehicle undergoing high intensity electromagnetic interference susceptibility testing. The data transmission system includes a fiber optic cable extending from the immediate vicinity of the truck to a site relatively remote to the truck and out of the effective area of the artificially generated electromagnetic interference. An optical/electrical coupler in close proximity to the motor vehicle is connected to the vehicle controller area network to convert messages occurring on the network to optical signals. The connection is provided by an electrical cable constructed of a twisted pair of wires. The optical/electrical coupler is also connected to an end of the fiber optic cable in the vicinity of the truck. A remote data processing device is attached to the remote end of the fiber optic cable by an interface card installed in the remote data processing device.

Abstract: The present invention is directed to receiver impedance calibration arrangements in full duplex communication systems.

Abstract: A testing device generates electromagnetic noise such as transients, power interruptions and Radio Frequency Interference (RFI) for application to an electronic device to test the immunity of the electronic device to electromagnetic noise or to test the performance of the electronic device during exposure to electromagnetic noise. The testing device promotes an economical and efficient evaluation of Electromagnetic Compatibility (EMC) of an electronic device during product design or otherwise. The testing device includes a switch having electrical contacts for producing electromagnetic noise during a transition between a closed state and an open state of the electrical contacts and a trigger that is coupled to the switch. The trigger is arranged to change states between the closed state and the open state of the electrical contact. An input terminal is associated with the switch for applying electrical energy to the switch.

Abstract: The power supply of equipment being tested for common mode noise problems is connected to a source of power with the power and neutral input terminals of the power supply isolated from the power ground. Recorded common mode noise signals are then inserted between the power supply's neutral input terminal and power ground to produce problem conditions. When the cause of the problem conditions are identified, steps are taken to eliminate the condition.

Abstract: A test system for measuring a frequency response of a signal path 148 by transmitting a short duration burst test signal 234 from a remote point 152, capturing an impaired burst test signal 432 on a digital signal acquisition unit 416, and analyzing the received signal by digitally processing it with an unimpaired burst test signal 434. A dynamic range test can also be performed with the same burst test signal by removing the energy in a part of the frequency band with a notch filter 232, and then increasing the power of the burst test signal level until non-linear distortion occurs. The distortion products will fill-in the notch, allowing the clipping threshold of the signal path to be measured. A burst trigger signal 244 generated by the transmitter device 201 causes a digital signal acquisition unit to acquire an impaired burst test signal.

Abstract: A test unit for measuring crosstalk in twisted pair cable. The test unit has an output signal balance (OSB) circuit that compensates for parasitic capacitance at its output terminals. The OSB circuit has a voltage controlled capacitance connected in circuit with each output terminal to control the effective capacitance between the output terminals and ground. The bias voltage for the variable capacitances is calibrated by a method in which the voltage for one of the variable capacitors is held constant while the voltage for the other capacitor is varied in voltage levels. A test signal frequency sweep is applied to the test unit output terminals. First and second voltage values are obtained and a final bias voltage value is calculated from using these two values.

Abstract: A method for evaluating radiation electric fields using output port powers of GTEM cell to obtain correlation between GTEM cell and Open Area Test Site(hereinafter, called OATS) in order to simulate electromagnetic wave radiation emission more accurate than GTEM(Giga-hertz Transverse Electromagnetic; hereinafter, called GTEM) cell, one of replacing facilities of OATS, a test facility for evaluating radiation emission for a test of electromagnetic interference(EMI). The adaption to a phase change of a dipole moment is very high by computing the electric field from a radiated matter using 15 GTEM cell output port powers as well as stably evaluating a radiation quantity upon considering the respective phase of the dipole illustrating an object due to various input values required in the algorithm.

Abstract: In a power supply (AC adapter etc.) of an electronic device, a first Y capacitor and a second Y capacitor are connected in series between two AC input lines which are connected to an input AC cable of the power supply so that input AC voltage will be divided, and a third Y capacitor for the prevention of EMI (Electro-Magnetic Interference) is provided between a grounding line on the secondary side of a transformer of the power supply and the connection point between the first Y capacitor and the second Y capacitor. The capacitance of the second Y capacitor is set larger than that of the first Y capacitor and the second Y capacitor having the larger capacitance is connected to a neutral-side AC input line which is connected to the neutral terminal of an AC socket.

Abstract: A test system method for measurement of crosstalk in a multi-pair cable of the type used in local area networks. The system uses a far end signal generator at one end of the cable and a near end signal generator at the near end of the cable. For a far end crosstalk measurement, the far end test unit transmits a high frequency far end test signal and a lower frequency reference signal on one of the wire pairs of the cable. The near end test unit responds to the received reference signal to generate a near end test signal in phase coherency with the far end test signal. A far and crosstalk measurement analysis is then conducted using the received far end test signal, the near end test signal and a crosstalk signal induced by the far end test signal in one of the other wire pairs of the cable.

Abstract: A method for controlling the power and/or frequency output of a digital data network's transmitters is described. The method controls the transmitter power and/or frequency output by using line loss information as well as the noise margin at both the central office and remote site sides of the transmission link. The transmitters are controlled to minimize the crosstalk between the interconnections on the network. Measurements are taken of the cable losses and signal-to-noise ratios present on the system and the transmitter power and/or frequency are adjusted to minimize unwanted interactions between transceiver pairs on the network.

Abstract: A test unit for measuring crosstalk in twisted pair cable. The test unit has an output signal balance (OSB) circuit that compensates for parasitic capacitance at its output terminals. The OSB circuit has a voltage controlled capacitance connected in circuit with each output terminal to control the effective capacitance between the output terminals and ground. The bias voltage for the variable capacitances is calibrated by a method in which the voltage for one of the variable capacitors is held constant while the voltage for the other capacitor is varied in voltage levels. A test signal frequency sweep is applied to the test unit output terminals. First and second voltage values are obtained and a final bias voltage value is calculated from using these two values.

Abstract: A test unit for measuring crosstalk in twisted pair cable. The test unit has an output signal balance (OSB) circuit that compensates for parasitic capacitance at its output terminals. The OSB circuit has a voltage controlled capacitance connected in circuit with each output terminal to control the effective capacitance between the output terminals and ground. The bias voltage for the variable capacitances is calibrated by a method in which the voltage for one of the variable capacitors is held constant while the voltage for the other capacitor is varied in voltage levels. A test signal frequency sweep is applied to the test unit output terminals. First and second voltage values are obtained and a final bias voltage value is calculated from using these two values.

Abstract: A test system having a bifilar wound isolation network disposed in between a device under test (DUT) and a device under test support system for providing a high isolation impedance to common mode signals present at the input terminals of the isolation network, while still providing a relatively lossless path for differential signals present across the input terminals of the isolation network. The isolation network comprises a plurality of four resonators each having a precise, predetermined number of turns and serially interconnected by a bifilar winding. The bifilar winding allows coupling to the inputs of a balanced DUT and enables a worst case operating environment to be provided for the balanced DUT to assist in testing and/or design of the DUT so as to minimize the effects on the DUT of electromagnetic interference and to assist in modifying the balanced DUT so as to immunize it from susceptible EMI receptors therewithin.

Abstract: Equipment under test is adjusted during set-up for electromagnetic compatibility testing. The equipment under test is placed on a base, such as a table, other structure or the ground. Positioners are connected to cables and/or subparts of the equipment under test. For example, the positioners are non-metallic pneumatic cylinders. The positioners are anchored to the base, to the device under test, or to some other structure. For various positions of an antenna relative to the equipment under test, positions of the positioners are found for which there is a maximum signal response. This is done by measuring signal response for current positions of the positioners. The current positions of the positioners are then varied using a remote control unit which controls positions of the positioners. This is repeated for as many different positions as desired. The positions which resulted in the maximum signal response is utilized for the electromagnetic compatibility testing.

Abstract: An RF-signal combiner-splitter comprises a microwave cavity that is intended to mix together radio signals in the 2.0 GHz spectrum. A hollow cylindrical metal tube with a volume of a few cubic feet to a few cubic yards is closed at one end and open at the other. Many RF-ports into the microwave cavity are provided at random positions that penetrate the hollow cylindrical metal tube. For example BNC-type bulkhead connectors with 10 dB attenuator pads are used with a 2 to 3 inch whip antenna inside the cavity volume. The attenuator pads brute-force an impedance match between the radio equipment under test and their corresponding RF-ports. The open end of the hollow cylindrical metal tube allows for the quick decay of RF-reflections that reverberate inside the cavity volume. Such open end is preferably directed toward nadir because interfering signals are generally minimum from that direction.

Abstract: An electrical cable containing two or more twisted pairs of wires and having terminals at one end connected to corresponding wires is tested for possible mis-pairing of an assumed wire pair. At that end of the cable, all terminals except the two for the assumed wire pair are connected to ground. A test signal is then applied to a first terminal for the assumed wire pair, and at the same time a measurement is made of a response signal received at the second terminal for the assumed wire pair. The test signal is a time-varying signal. The strength of the response signal is compared to the test signal to establish whether the assumed pair of wires are in fact wound to each other.

Abstract: In an apparatus for EMC testing of electrical devices, conductors are arranged at opposite sides of a chamber of conductive material at a spacing from and parallel to the chamber walls. These conductors form a symmetrical double line and are fed out of phase at one end by a radio frequency source. They are electrically connected to the chamber walls at the other end via terminating impedances.

Abstract: A method for measuring interference in a cable transmission system includes the step of establishing a spectrum frequency measurement window having start and stop frequencies and an amplitude threshold. Data is acquired over the window representative of the spectral energy of the cable transmission system within the window and the data is compared against the threshold value. If the data falls below the threshold value, indicating the absence of a carrier signal within the window, a display is generated characterizing the interference over the window. Additional measurement windows may be established having different start and stop frequencies and thresholds for measuring different portions of the cable transmission system frequency spectrum.

Abstract: A system for protecting an electronic device from electromagnetic radiation is provided that receives electromagnetic radiation impinging on said electronic device, determines a value of a characteristic of said electromagnetic radiation, generates a testing signal when said value of said characteristics of said electromagnetic radiation is greater than a predetermined value, and tests said electronic device in response to said testing signal to determine if said electromagnetic radiation has affected said electronic device. A method for protecting an electronic device from electromagnetic radiation is also provided.

Abstract: The invention describes a method and an apparatus for generating and receiving electromagnetic waves for test purposes and is applicable particularly for measurements, investigations and tests of electromagnetic compatibility. For testing the immunity, the test piece is acted upon with defined field parameters and, during the emission measurement, the electromagnetic radiation emitted by the test piece is measured. It is an important distinguishing feature of the invention that a cell, constructed as a TEM waveguide, is rotated about the test piece. The apparatus is characterized in that the lid and bottom of the pyramidal cell are constructed so as to be electrically conducting and in that two-dimensional septa, which consist of individual wires of equal length, are disposed in each case symmetrically at a small distance from the lid and the bottom.

Abstract: A pulse-based local area network (LAN) cable test instrument provides a measurement of the cross-talk characteristic of a LAN patch cord as a function of frequency in order to evaluate its relative performance and workmanship of assembly. A LAN cable test instrument applies a test signal in the form of narrow pulses to a selected transmission line of a LAN patch cord while the cross-talk response induced in another transmission line in the same LAN patch cord is measured and stored as a time record in digital memory. The near-end and far-end pulse responses are separated in the time record, leaving only the near-end pulse response. The LAN cable test instrument analyzes the near-end pulse response by performing a discrete Fourier transform on the time record to provide cross-talk versus frequency information. The same test may then be performed on the far-end end of the patch cord to obtain a complete test of the quality of workmanship at both ends of the patch cable.

Abstract: A method for measuring an adjacent channel power of a device under test (DUT) such as a radio transmitter. The method comprises the steps of performing a frequency conversion to convert a transmitting signal of the DUT to an intermediate frequency signal; sampling the intermediate frequency signal to convert it to a digital signal; resolving the digital signal into an in-phase component and a quadrature component by a quadrature detection; removing a high frequency component from each of the in-phase and quadrature components; executing a complex Fourier transformation for the in-phase and quadrature components to obtain a frequency spectrum; and computing the leakage power to the adjacent channel from the frequency spectrum.

Abstract: A 6 port TEM cell for measuring garbage EMI/EMS of an electrical and electronic equipment which can form an electromagnetic field of horizontal/vertical polarization using characteristic that internal electric field polarization is changed according to feeder line selection inside a multi-transmission line, and coupling amount among internal conductors is reduced by positioning the spherical internal conductors at corners of external conductors, thereby widening a test area.

Abstract: A communication circuit capable of accurately detecting the signal level of the transmitted signal without impairing interchangeability with respect to an existing communication circuit. The communication circuit includes a first arithmetic unit 110 and a second arithmetic unit 120. The first arithmetic unit 110 executes arithmetic operations ofK=R1/(R1+R2)V4=V3-K.times.V1where V1 is a voltage of a transmission signal on a receiving side 100, R1 is a transmission impedance on the receiving side 100, V2 is a voltage of the transmission signal on a transmitting side 200, R2 is a transmission impedance on the transmitting side 200 and V3 is a voltage of the transmission signal transmitted to the receiving side 100 via a control line CL interconnecting the transmitting side 200 and the receiving side 100. The second arithmetic unit 120 executes an arithmetic operation ofV5=2.times.

Abstract: The apparatus includes a first transmitter for transmitting a first test signal from a first end of the cable and a second transmitter for transmitting a second test signal from a second end of the cable. The first test signal is transmitted on a first conductor pair at a first frequency and the second test signal is simultaneously transmitted on a second conductor pair at a second frequency. The apparatus also includes a first receiver for receiving a first coupled signal at the first end of the cable and a second receiver for simultaneously receiving a second coupled signal at the second end of the cable. The first coupled signal exhibits the first frequency and is received on a third conductor pair, while the second coupled signal exhibits the second frequency and is received on a fourth conductor pair. The transmit frequencies are offset such that interference and noise are not detected by the receivers as coupled signals.

Abstract: A network analyzer system employs a calibration and measurement technique (300) to compensate for probe tip cross-talk. Calibration technique (310) calibrates standards (400, 500, 600) having variable probe separations. Error terms are produced for each separation. Continuous functions (702, 704, 706) are developed for the error terms as a function of distance. A device under test (802) can then be measured and a set of error terms is generated based on the separation between the probes. These error terms (902) are then used to correct the measurement of the device under test (802). A device under test (802) can thus be measured with various probe tip separations and differing impedances without having to re-calibrate the network analyzer.

Abstract: An efficient method for calculating Power Sum cross-talk loss is provided. Cross-talk loss measurements may include near-end cross-talk (NEXT) loss, far-end cross-talk (FEXT) loss, multiple disturber NEXT (MD NEXT) loss, and multiple disturber FEXT (MD FEXT) loss. Pair-to-Pair cross-talk loss responses are collected between a given wire pair and all the other wire pairs of concern, with each pair-to-pair cross-talk loss measurement having a number of frequency data points corresponding to the frequencies of interest. The pair-to-pair cross-talk loss response having the lowest positive value for a particular frequency data point is first selected as the baseline cross-talk loss response. The effects of each of the remaining pair-to-pair cross-talk loss responses on the baseline cross-talk loss response are then accounted for by applying power sum contribution values obtained from a look-up table.

Abstract: Apparatus and method for low cost monitoring the level of signal at a test point in a system for susceptibility to electromagnetic fields. A probe, including a detector diode, and a non-metallic, electrically overdamped conductor, which is transparent to the electromagnetic field, is used to monitor the signal level at a test point as an amplitude modulated radio frequency carrier. The carrier is transmitted to a monitor outside of the range of the electromagnetic field using a transmission link, such as an optical waveguide transmitter, that is transparent to the electromagnetic field when the system under test fails. The probe may include a plurality of detector diodes mounted on a printed circuit board in a shielded structure that is directly connected to the test wire of the circuit to be monitored.

Abstract: A pulse-based LAN cable test instrument that processes time-domain cross-talk measurement information in order to troubleshoot and quickly locate sources of cross-talk as a function of distance along the LAN cable system is provided. A pulse-response time record between a pair of transmission lines of the LAN cable system is first acquired. A series of steps to process the time-domain pulse response data in the time record are then performed to enhance the ability of the user to locate and troubleshoot the primary contributors to NEXT along any point of the LAN cable system. The pulse response data are first normalized as a function of distance from the LAN cable test instrument in order to compensate for losses along the LAN cable. Next, the pulse response data are integrated over the time record and the absolute value of the pulse response data is calculated to more clearly show the individual sources of cross-talk within the overall LAN cable pulse response.

Abstract: An instrument and method for the troubleshooting and verification of copper-wire local area network (LAN) cable systems provides a series of resistance and capacitance measurements between all possible wire pairs using a pair of switch matrices and a software method for evaluating the measurements which are stored in a two-dimensional matrix. The stored measurements are evaluated against predetermined figures of merit and the decision pattern in matrix form is compared to that of a known good LAN cable system. Error messages responsive to mismatches are generated and presented to the operator via a user interface. Near-end cross talk (NEXT) isolation is evaluated using a mathematically calculated differential capacitance technique. Error messages are generated responsive to difference capacitance values larger than a figure of merit correlated to an acceptable level of NEXT isolation.

Abstract: A cable crosstalk measurement system provides fault diagnostic information to locates faults in addition to providing a crosstalk versus frequency function to test and troubleshoot LAN cables. In a preferred embodiment, a narrow pulse is introduced into one twisted pair of a standard LAN cable, and another twisted pair in the same cable is monitored for crosstalk signal coupling. A measurement system digitizes crosstalk signals using sequential sampling of repetitive signals to provide a waveform record that is a reconstructed equivalent time representation of a real-time crosstalk signal. A microprocessor performs a fast Fourier transform of the waveform record to provide crosstalk versus frequency information, while the waveform record is also examined for higher-than-acceptable amplitude levels to locate poor quality or faulty connectors and cables.

Abstract: A termination control circuit is coupled to a far end of a cable. A modulated test signal is reflected back to a near end of the cable at a different frequency but at substantially the same level of attenuation as the test signal. Signal attenuation in the reflected signal is then measured to determine the amount of attenuation in the test signal. A second embodiment of the termination control circuit measures crosstalk by enabling and disabling termination resistors at the far end of the cable. A DC bias voltage located at the near end of the cable selectively turns on switching diodes to enable the termination resistor. Alternatively, both the attenuation and crosstalk circuits are combined together allowing both signal attenuation and crosstalk measurements with the same termination control circuit.

Abstract: Development of worst case operating environment, interfering parameters of a test item, is effected by a decoupling device. The device includes a series of resonators configured and interconnected in a particular manner along with a shunt capacitance. Each resonator has a torroidal core formed from a ferrite composition. When connected between the test item and its support system, the device provides such an impedance to signals other than those needed for normal operation, that the highest noise voltage levels emit from the test item. These levels permit developing repeatable worst case interference parameters which provide a guide for modifying the test item circuit components and connectors so as to minimize the effects of generating EMI sources or to immunize susceptible receptors within the test item.

Abstract: An instrument to measure crosstalk between conductor pairs is configured to transmit a signal at one pair and receive the signal at another pair. The spureous or parasitic crosstalk at the connectors is supressed using a vectorial substraction from the received signal.

Abstract: A pulse-based cable crosstalk measurement instrument provides near-end cross talk (NEXT) information for characterizing the performance of local area network (LAN) cable systems. Accuracy of the cross-talk measurement is enhanced by measuring and mathematically removing the cross-talk effects of the near-end connector. Accuracy of the cross-talk measurement is further enhanced by conducting the cross-talk measurement with pulses of differing pulse widths selected to have increased pulse energy in frequency ranges of interest. A composite cross-talk response using the individual cross-talk responses of the individual pulse widths concatenated together is created and then compared with an industry-standard pass fail limit to provide a pass-fail decision on a LAN cable test system under test.

Abstract: An apparatus for measuring an electromagnetic wave stress of an article includes an electromagnetic wave irradiation unit comprising a plurality of radiation probes being adjacent to each other along a surface of the article at least on one side thereof so as to permit the probes to irradiate independently electromagnetic waves on divided local areas on a surface of the article corresponding to the locations of the probes. The apparatus also includes a control unit electrically connected to the article for receiving output signals having information as to existences of any abnormalities in individual divided local areas in the article exposed to an electromagnetic wave irradiation, the control unit being electrically connected to the transmitted unit for controlling operations of the transmitter unit to control independently an excitation of each radiation probe.

Abstract: Apparatus to measure the crosstalk between pairs of conductors in a cable. The measurements are affected by the crosstalk inherent to the connectors that are part of the apparatus. The improvement consists of adding a compensating signal which equals that from the connector crosstalk in magnitude but has opposite sign.

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: An electromagnetic disturbance power (EDP) checker measures disturbance waves of an equipment under test (EUT), that is, a small electric appliance having a power cord. The EDP checker is capable of detecting and measuring disturbance waves even in sites more confined and having more external disturbance waves than in absorbing clamp method. The EDP checker includes a VHF current probe 2, a matching circuit 3 having input impedance matched at a reception frequency of a measuring equipment (receiver) 6 connected to the VHF current probe 2, and a circuit separating mains 4 for designating terminal impedance of the matching circuit 3 and eliminating influence of power source impedance. Power is supplied from the circuit separating mains 4 to drive the EUT 5 connected to the VHF current probe 2. The maximum value of disturbance power generated by the EUT 5 and supplied through the power cord 12 is measured by the measuring equipment 6 connected to the VHF current probe 2.

Abstract: A coupling network for electromagnetic pulsed testing arrangements includes three stacks of toroidal ferrite cores. Two of the stacks are of identical diameter, the third stack has a diameter approximately equal to the combined diameters of the first two stacks. A copper tube looped through the central aperture of the first two stacks forms a primary winding. An insulated wire looped twice through the first two apertures forms a secondary winding of a 1:2 step-up transformer. The winding is extended through the aperture of the third stack. The third stack is operable to permit the laying in of a cable connected to a device under test. The cable forms the secondary of an isolation transformer.

Abstract: A method and apparatus for fast response and distortion measurement of a signal transfer device. A computer processor generates a multitone test signal of predetermined duration and stores it in a memory. The test signal is read out, converted to analog form, if necessary, and applied to the input of a device under test. The output produced by the device under test in response to the test signal is acquired and digitized, if necessary, and a Fast Fourier Transform is performed on the acquired data to determine its spectral characteristics. Frequency response, harmonic distortion, intermodulation distortion, phase distortion, wow and flutter and other signal transfer characteristics are measured by the CPU by analysis of the output signal.

Abstract: Apparatus for measuring electromagnetic radiation from an electronic component in which a transverse electromagnetic cell has a coaxial connector for receiving radiation, a septum extending from the connector to a facing wall of the apparatus, the facing wall having a flat surface and formed from ferrite particles dispersed through rigid material. The rigid material is ceramic and conveniently the facing wall is made from ceramic tiles incorporating the ferrite particles. With this wall structure, the apparatus may be of small size suitable for measuring radiation or electronic chips or connector assemblies.

Abstract: The device is of the type comprising a closed test cell the periphery of which is defined by an outer conductor of a TEM waveguide constituted by a tubular casing. An inner conductor of the waveguide extends within the cell. The casing has at least one intermediate portion of uniform rectangular cross-section, in which there is a test region for accommodating an object under test. At least in the intermediate portion, the inner conductor has a substantially arcuate transverse profile, the concave side of which faces the object under test. The inner conductor is preferably constituted by an array of transversely spaced-apart parallel wires arranged so that the array has the said arcuate profile.

Abstract: An apparatus and method for monitoring voltage on a LAN cable on which data is conveyed by negative-going pulses. Positive voltage on the LAN cable is interpreted as noise. Positive voltage is detected by, for example, comparing the voltage on the LAN cable to a positive reference voltage, determining the peak positive voltage on the LAN cable, or determining the average positive voltage on the LAN cable. Upon the detection of positive voltage on the LAN cable, the presence (and possibly the amount) of noise is indicated to a person or data processing system which supervises the LAN called a LAN sentinel. The apparatus or method could be implemented in a Media Attachment Unit (MAU) with audio, visual or electronic noise indication means. Alternatively, it could be implemented as a hand-held diagnostic tool.

Abstract: An arrangement of digital circuitry is disclosed for testing a cable communication system to determine its performance when subjected to near-end cable crosstalk. The circuitry digitally generates a crosstalk signal indicative of the combined effect of one or more interfering sources and the near-end crosstalk coupling path linking the interfering sources with the system-under-test. The circuitry includes a pseudo-noise sequence generator for producing a stream of bits that are normally distributed and a digital filter, responsive to the sequence generator, for implementing a frequency characteristic corresponding to the spectral content of the interfering source as weighted by the near-end crosstalk path.

Abstract: For the reduction of noise signals, and particularly crosstalk signals, in measurement systems for analyzing emission or transmission processes and composed of a serial arrangement of a signal source (1), a measurement path (2) with or without a transmission test object (8), a detector (3), and a measurement and display circuit (5), an identification modulation is imparted to the signal component carried in the measurement path by means of repeated modulation (6, 9). The evaluation of the detector output signal may be performed with respect to a frequency which is free of the effects of the single modulation signals occurring in the detector output signal because of noise pick-up. Use of this method in homodyne systems for quadrupole parameter measurements further eliminates the effects of crosstalk reflections which typically occur in these systems.

Abstract: An apparatus for determining the electromagnetic compatibility of a system, including a wide-band frequency source 2, optionally subject to frequency and amplitude modulation, and coupled to a cable 9 of the system. Accuracy may be improved by the addition of a current measuring arrangement 11, 12. The two coupling devices may be split and assembled into hinged frames to facilitate use.