Abstract: A method and apparatus for detecting faults in cables. The invention comprises computing a plurality of thresholds representing a corresponding plurality of values of reflections in the cable; comparing a received reflection to a given threshold; if the received reflection value is greater than the given threshold value, then determining the location of the cable fault; and if the received reflection is not greater than the given threshold value, then taking no further action.

Abstract: A method and apparatus for detecting faults in cables. The method and apparatus comprise receiving a reflected signal; multiplying an estimation of the reflected signal from an echo canceller by a predetermined gain factor; subtracting the value obtained as a result of the multiplication from the received reflected signal; and generating an error signal to adapt the echo canceller tap weight to match the real received reflected signal.

Abstract: A method for inspecting a semiconductor device includes establishing a first circuit state in which electrical conduction through at least one of branch transmission line portions is established and electrical conduction through at least one other branch transmission line portion is prevented. Then, electrical signal reflection characteristics of the transmission line are measured. The method also includes establishing a second circuit state in which electrical conduction through the at least one of the branch transmission line portions is prevented and electrical conduction through the at least one other branch transmission line portions is established. Then, the electrical signal reflection characteristics of the transmission line are measured. The second circuit state is a mirror image of the first circuit state with respect to the primary transmission line. The measured values are compared.

Abstract: A system for identifying elements in a cable network utilizing frequency domain reflectometry includes initial filtering stages to remove noise, second and third harmonics and side lobes, and subsequent identification stages to identify and display various elements, e.g. splitters, barrels and opens, in the cable network and their relative positions.

Abstract: A physical layer device includes a cable tester that determines a cable status of a cable and that includes a test module. The test module transmits a test pulse on the cable, measures a reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. An insertion loss estimator communicates with the cable tester, and estimates insertion loss of the cable based at least in part on a feedback equalizer gain.

Abstract: The invention provides a method for testing a transmission medium used in a full-duplex communication system comprising an endpoint that comprises a transmitting end (TX) and a receiving end (RX); the method comprises the steps of: first, transmitting a transmitted signal which comprises a test signal sequence with a high auto-correlation characteristic; then, receiving a received signal, and performing a correlation operation on the test signal and the received signal; finally, according to the result of the correlation operation, determining the impedance matching condition of the transmission medium.

Abstract: A technique for reflectometry testing of a signal path is disclosed. The technique includes injecting a test signal based on a probe pseudo-noise sequence into the signal path and obtaining a response signal. A sliding reference pseudo-noise sequence is correlated against the response signal. Both the probe sequence and the reference sequence are generated at a chip rate. The correlation is obtained for integer chip time delays, and sub-chip resolution of a peak correlation delay is estimated from at least two samples of the correlation.

Abstract: Methods for determining capacitance values of a metal on semiconductor (MOS) structure are provided. A time domain reflectometry circuit may be loaded with a MOS structure. The MOS structure may be biased with various voltages, and reflectometry waveforms from the applied voltage may be collected. The capacitance of the MOS structure may be determined from the reflectometry waveforms.

Abstract: A method is provided that includes receiving a detection voltage at a powered device from a powered network, applying the detection voltage to an external resistor to provide a detection signature to the powered network, and applying a reference voltage to the external resistor to generate a reference current after the detection signature has been provided to the powered network.

Abstract: The present invention relates to a method and an apparatus for TDR (time domain reflection) test of a transmission line. In the method, first, a test signal meeting the test requirement of self-correlation and mutual-correlation is determined and transmitted in the transmission line, in which the test signal may be a band-limited random signal, a frequency agility signal, or a regular frequency modulation signal. Then, a TDR test is performed according to the test signal transmitted in the transmission line. The SELT (Single-End Line Test) apparatus configured in accordance with the TDR test solution in the present invention has a good adaptability to environment, a high test accuracy, and an excellent capability of noise resistance. The method of the present invention is very useful for TDR test of large-scaled DSLAM (DSL Access Multiplexer) equipments.

Abstract: A test method and a semiconductor device is disclosed. One embodiment provides sending out a test signal by a semiconductor device. A reflected signal generated in reaction is compared to the test signal with a first threshold value. The reflected signal is compared with a second threshold value differing from the first threshold value.

Abstract: The location of high resistance ground faults within buried co-axial power cables can be detected by transmitting a combined signal along the cable at a primary frequency of 0.718 Hz and a primary amplitude in the order of 4,500 volts peak to peak. This combined signal also has an interlocked secondary frequency of 11,780 Hz superimposed on the primary frequency. The ratio between the reactive impedance and resistive impedance is such as to create a condition where the 0.718 Hz primary frequency's single source caused resistive current is usually larger than the sum or total of all that cable's per foot of length's 0.718 Hz reactive currents. This condition then enables the detection of the resistive ground faults by a manually transported Receiver. When needed the effective resistance and/or capacitance of the cable can be increased by a remote end connection circuit.

Abstract: A method of determining the state of a cable comprising at least one electrical conductor, uses a generated test signal and applies it to at least one conductor by a non-contact coupling transmitter. The resulting signal is propagated along the at least one conductor and a non-contact electrical coupling receiver picks up a reflected signal, and compares the reflected signal to expected state signal values for the cable to determine its current state.

Abstract: A system and method are used to determine connectivity and/or cable faults of a cable. A signal transmitting and receiving system is coupled to the cable. An analog-to-digital converter (ADC) coupled to the signal transmitting and receiving system. A TDR system coupled to the ADC and a memory, and a controlling system coupled to at least one of the ADC, the TDR system, and the signal receiving and transmitting system. The controlling system includes a controller and one or more state machines that are used to control the TDR system.

Abstract: A system or method of analyzing a conductive member for the presence an anomaly. A conductive pipe member is analyzed for the presence an anomaly the electromagnetic properties of which are non-linear. The electromagnetic properties of the pipe member at the anomaly are altered by applying a direct current perturbation signal to the pipe member. At least one test source signal is applied to a first test location on the pipe member remote from the anomaly to cause the at least one test source signal to travel along the pipe through the anomaly. At least one test return signal associated with the at least one test source signal traveling through the anomaly is detected. The at least one test return signal is analyzed for characteristics associated with the anomaly.

Abstract: A circuit breaker detects a loose electrical connection condition of a power circuit. The circuit breaker includes first and second lugs, first and second acoustic couplers acoustically coupled to the power circuit, separable contacts electrically connected in series between the first and second lugs, and an operating mechanism adapted to open and close the contacts. An acoustic generator is coupled to the second acoustic coupler and generates a first acoustic signal to the power circuit from the second acoustic coupler. An acoustic sensor is coupled to the first acoustic coupler and has a second acoustic signal which is operatively associated with the loose electrical connection condition. The acoustic sensor outputs a sensed acoustic signal. A circuit cooperates with the acoustic generator to generate the first acoustic signal, input the sensed acoustic signal, and detect the loose electrical connection condition therefrom.

Abstract: A cable tester that tests cable and that determines a cable status includes a pretest module that senses activity on pairs of the cable and that selectively enables testing based on the sensed activity. A test module is enabled by the pretest module, transmits a test pulse on one of the pairs, measures a reflection amplitude and calculates a cable length. The cable status includes an open status, a short status, and a normal status. The test module determines the cable status based on the measured amplitude and the calculated cable length. The test module measures received signals on at least one other pair after transmitting the test pulse on the one of the pairs, compares the received signals on the at least one other pair to a predetermined threshold, and determines a pair short status between the one of the pairs and the at least one other pair if the received signals exceed the predetermined threshold.

Abstract: A device for testing data communications cabling. The device consists of a signal generator that can generate a test signal to test the data communications cabling and a receiving component that can receive a reflected signal produced by reflection of the test signal from the data communications cabling including any reactive point source disturbance that may exist on the cabling. The receiving component can determine characteristics of the reflected signal by analyzing the phase rotation and amplitude of the reflected signal. The device can also include a cancellation generator that can generate a cancellation function based on the characteristics of the reflected signal. The cancellation function can substantially negate a portion of the reflected signal.

Abstract: Systems and methods are disclosed to construct subsurface images from diffuse seismic energy. Various disclosed system embodiments include multiple seismic sensors that each convert received seismic energy into one or more seismic signals. One or more processor combine the seismic signals to determine a subsurface map. As part of determining the map, the processor(s) systematically focus the array of seismic sensors on each bin in the subsurface volume of interest. In this manner each bin becomes a focal point of the array. For each bin, the processor(s) analyze the seismic wave travel time to each seismic sensor and apply a corresponding time shift to align the seismic signals with a uniform travel time. The time-shifted seismic signals are then combined to determine an intensity value for seismic energy radiating from the focal point. A subsurface map can then be derived from the intensity value as a function of position.

Abstract: Systems and methods are described for transmitting a waveform having a controllable attenuation and propagation velocity. An exemplary method comprises: generating an exponential waveform, the exponential waveform (a) being characterized by the equation Vin=De?ASD[x?vSDt], where D is a magnitude, Vin is a voltage, t is time, ASD is an attenuation coefficient, and vSD is a propagation velocity; and (b) being truncated at a maximum value. An exemplary apparatus comprises: an exponential waveform generator; an input recorder coupled to an output of the exponential waveform generator; a transmission line under test coupled to the output of the exponential waveform generator; an output recorder coupled to the transmission line under test; an additional transmission line coupled to the transmission line under test; and a termination impedance coupled to the additional transmission line and to a ground.

Abstract: A physical layer device comprises a first port adapted to communicate with one end of a cable. A second port is adapted to communicate with an opposite end of a cable. A cable tester communicates with the first and second ports and selectively tests the cable to determine a cable status, which includes an open status, a short status, and a normal status. The cable tester includes a test module that transmits a test pulse on the cable, measures a reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A frequency synthesizer selectively outputs a plurality of signals at a plurality of frequencies on the first port. An insertion loss calculator that receives the signals on the second port and that estimates insertion loss.

Abstract: A physical layer device comprises a first transceiver that selectively communicates with a cable medium. A detector detects a power over Ethernet (POE) device. A switching device selectively provides power from a power supply over the cable medium when the detector detects the POE device. A cable tester communicates with the first transceiver, tests the cable medium and determines a cable status, and delays testing of the cable medium when the detector detects the POE device until the switching device provides the power.

Abstract: Cable diagnostic test methods, systems and apparatus are disclosed that utilize “standing wave” principles to facilitate identification and location of insulation defect(s) along a power cable. The methods/systems measure dissipation factors and dielectric constants associated with the power cable insulation and the impedance of the power cable conductor at any number of points or sections along the axial length of the cable.

Abstract: A method and apparatus for measuring data rates is disclosed. An apparatus that incorporates teachings of the present disclosure may include, for example, a diagnostic system having a Time Domain Reflectometer (TDR) element that submits a signal over a cable and determines from its reflection in the cable a length of the cable and a length of a bridged tap, and a diagnostic element that determines downstream and upstream bit rates for the cable according to the length of the cable and the length of the bridged tap. Additional embodiments are disclosed.

Abstract: A method for network diagnosis between a source end and a destination end coupled by a transmission line is provided. The method includes the following steps. First, a first test signal is transmitted from the transmitter to the receiver when the hybrid is set to a first mode. Next, a plurality of first coefficients are extracted from the first test signal received by the canceller during a first period, wherein each one of the first coefficients has an index corresponding to a received order. And then, the hybrid is switched to a second mode to generate a second test signal by sending an original signal to the receiver and the destination. Sequentially, a plurality of second coefficients are extracted from the second test signal received by the canceller during a second period, wherein each one of the second coefficients has an index corresponding to a received order. Therefore, a first index is determined when an absolute value of one of the first coefficients substantially exceeds a first threshold value.

Abstract: A single ended line testing method for qualifying an electrically conducting line, including the steps of sending a plurality of randomized excitation signals from a first end of the line towards a second end of the line, subsequently taking measurements, at the first end of the line, of each reflection of the plurality of randomized excitation signals, and then inversely randomizing the measurements. Line qualification is determined based on an average of the inversely randomized measurements.

Abstract: A method of correcting distortions resulting from loss and dispersion in cable fault measurements. A cable is measured in the frequency domain to obtain a reflected response. Fractional sinusoidal components of the reflected response having attenuated amplitude and delayed phase values at points defining the junctures of adjacent equal predetermined lengths are collected and normalized. Then the fractional sinusoidal components of the reflected response are extracted from normalized sum by mathematically calculating the real value at each point, thereby removing all loss and dispersion distortion components.

Abstract: A method and apparatus for mapping a wire network is disclosed. The method includes obtaining a reflectometry test signal of the wire network. An estimated network impulse response is estimated from the reflectometry response. A wire network model is then initialized, and iteratively improved by simulating an impulse response of the wire network model and adjusting the wire network model to reduce differences between the simulated impulse response and estimated network impulse response.

Abstract: A cable tester tests cable to determine a cable status. A mode selector selects one of a first operating mode and a second operating mode. A pretest module senses activity on the cable and selectively enables testing based on the sensed activity when in the first operating mode and enables testing when in the second operating mode. A test module is enabled by the pretest module, transmits a test pulse on the cable, measures a reflection amplitude and calculates a cable length. The cable status includes an open status, a normal status and a short status. The test module determines the cable status based on the measured amplitude and the calculated cable length.

Abstract: A technique for testing a signal path while an operational signal is present is disclosed. The technique may be performed without injecting a test signal into the signal path by using an operational signal already present in the signal path. A method of testing a signal path includes receiving an operational signal from the signal path and estimating a correlation of the operational signal. A system for testing a signal path includes an extractor configured to extract a sample of the operational signal when coupled to a signal path and a correlator configured to estimate a correlation of the operational signal. Various properties of the signal path may be determined using the technique.

Abstract: A method of characterizing a signal path includes (i) generating a reference spread-spectrum signal; (ii) coupling the reference spread-spectrum signal into the signal path while the signal path is carrying an operational signal; (iii) receiving a reflected spread-spectrum signal from the signal path generated in response to the reference spread-spectrum signal; and (iv) correlating the reflected spread-spectrum signal with the reference spread-spectrum signal to produce a correlation result corresponding to a characteristic of the signal path.

Abstract: A cable tester comprises a test initiating module that performs B cable tests. Each of said B cable tests includes selectively transmitting a test pulse on the cable, measuring a reflection amplitude, and calculating a cable length. A test results module determines a cable status for each of said B cable tests based on said measured amplitude and said calculated cable length and that determines an overall cable status of the cable based on the cable at least one of passing and failing A out of B cable tests. A and B are integers greater than zero and B is greater than A.

Abstract: A novel mechanism for performing high accuracy cable diagnostics. The mechanism utilizes time domain reflectometry (TDR) to detect and identify cable faults, perform estimations of cable length, identify cable topology, identify load and irregular impedance on metallic paired cable, such as twisted pair and coaxial cables. The TDR mechanism transmits pulses whose shapes are programmable and analyzes the signal reflections. The shapes of the pulses transmitted can be optimized in accordance with the channel characteristics. Further, the TDR mechanism is adapted to operative in the presence of high pass filters in the channel.

Abstract: An apparatus for detecting concealed surveillance devices coupled to a transmission line uses either a time domain or frequency domain reflectometry operation to locate any impedance anomalies on the transmission line and a non-linear junction detection operation to classify the located impedance anomalies as semiconductor or non-semiconductor based anomalies. The reflectometry operation utilizes the reflection of a test signal to determine the distance to any reflecting impedance anomalies on the transmission line that may be indicative of an electronic device being coupled to the transmission line. The non-linear junction detection operation then compares the amplitudes of re-radiated second and third harmonics of a transmitted fundamental frequency signal to determine if the reflecting impedance anomalies are the result of a semiconductor based non-linear junction. A DC bias voltage and a balanced load may be added to the transmission line to enhance the line's response to the test signals.

Abstract: A system or method of analyzing a conductive member for the presence an anomaly. A test source signal is applied to a first test location on the elongate conductive member remote from the corrosion to cause the test source signal to travel along the pipe through the anomaly. At least one test return signal caused by the test source signal traveling through the anomaly is detected. The at least one test return signal for characteristics associated with the anomaly. Optionally, a perturbation may be applied to the elongate conductive member to place the conductive member in a perturbed state in which the electromagnetic characteristics of the conductive member at the anomaly are altered. The test source signal is applied to the first test location when the conductive member is in the perturbed stated.

Abstract: An algorithm is provided for a frequency domain reflectometer which takes into account both attenuation per unit length of transmission line and phase shift per unit length of transmission line in a modified Inverse Fourier Transform that converts a frequency domain complex reflection coefficient into a more accurate time domain reflection coefficient so that the distance to a fault can be readily determined.

Abstract: A system and method are used to determine connectivity and/or cable faults of a cable. A signal transmitting and receiving system is coupled to the cable. An analog-to-digital converter (ADC) coupled to the signal transmitting and receiving system. A TDR system coupled to the ADC and a memory, and a controlling system coupled to at least one of the ADC, the TDR system, and the signal receiving and transmitting system.

Abstract: A digital time domain reflectometer system is provided for performing a measurement process that is useful for calculating a cable length. The measurement process starts with a launch controller periodically generating a sync signal for turning a duration signal on. After a known delay time, the launch controller launches a signal on a cable, and if a reflected signal is detected, a detection circuit turns the duration signal off. A counter counts the number of clock pulses in the duration signal. This system is made more accurate by performing the measurement process multiple times and averaging the results. Using the averaged results, and compensating for the added known delay time, the cable length is calculated. An adaptive threshold may be used to enhance measurement accuracy.

Abstract: Described are techniques used in a wire diagnostics system to detect events, such as defects, that may occur within a wire or cable under test. An incident voltage signal is sent out on the wire and a measured voltage signal is obtained which includes the incident voltage and the reflected voltage. Compensation processing is performed on the measured waveform to remove unwanted reflective components. Additionally, the waveform is then subject to attenuation processing and event detection processing. Detected events, such as defects, are classified and output as results. Events are classified by parametric classification using a library of known events or faults. The library of known events or faults is previously generated using empirical analysis and modeling techniques. Additionally, joint time-frequency domain reflectometry (TFDR) techniques are described for event identification and classification for a wire under test.

Abstract: The present invention relates to a single ended line testing method for qualifying an electrically conducting line. This method includes the steps of sending a plurality of excitation signals from a first end of the line towards a second end of the line and before the sending of this plurality of excitation signals, randomizing each excitation signal of the plurality of excitation signals. Subsequently, measurements are performed, at the first end of the line, of each reflection of the plurality of excitation signals sent towards the second end of the line. Then an inverse randomization on each of the measurements of reflections is performed which is succeeded by determining an average of all the measurements of reflections of the excitation signals. Finally, from the average a qualification of the electrically conducting line is determined.

Abstract: In a system and method for testing and displaying the abnormalities, includes opens, shorts, bridged-taps and wet sections, of a copper pair line for xDSL service use, the abnormalities are amplified and normalized so as to be displayed within a predetermined observation range. The normalization steps include piecewise gaining and biasing the reflected pulse of various gains to create a first normalized reflected trace which match the reflected traces within a predetermined observation range and thereby constitute a total smooth curve; and amplifying the first normalized reflected trace according to a function of time to create a second normalized reflected trace so as to eliminate an exponential gain decay curve of a no-fault copper pair line with the same predetermined characteristic parameters from the first normalized reflected trace to thereby obtain a second normalized reflected trace showing any amplified abnormalities.

Abstract: A system and method are used to determine connectivity and/or cable faults of a cable. A signal transmitting and receiving system is coupled to the cable. An analog-to-digital converter (ADC) coupled to the signal transmitting and receiving system. A TDR system coupled to the ADC and a memory, and a controlling system coupled to at least one of the ADC, the TDR system, and the signal receiving and transmitting system. The controlling system includes a controller and one or more state machines that are used to control the TDR system.

Abstract: A physical layer device including a first port and a second port comprises a cable tester that communicates with the first and second ports and that determines a cable status, which includes an open status, a short status, and a normal status. Opposite ends of a cable selectively communicate with the first and second ports. The cable tester includes a test module that transmits a test pulse on the cable, measures reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A frequency synthesizer communicates with the cable and that selectively outputs a plurality of signals at a plurality of frequencies on the first port. An insertion loss calculator receives the signals on the second port and that estimates insertion loss.

Abstract: An apparatus for monitoring the integrity of a wire is provided, which includes a TDR instrument for generating a pulse waveform for transmission through the wire. The apparatus also includes a function generator for generating an electrical or non-electrical forcing waveform for transmission through the wire. The pulse waveform is transmitted through the wire in combination with the forcing waveform and a detector measures a change in dissipation factor values along the wire.

Abstract: A cable tester tests cable to determine a cable status. The cable status includes an open status, a normal status and a short status. A pretest module senses activity on the cable and selectively enables testing based on said sensed activity. A test module is enabled by the pretest module, transmits a test pulse on the cable, measures a reflection amplitude and calculates a cable length. The test module determines the cable status based on the measured amplitude and the calculated cable length.

Abstract: A physical layer device includes a cable tester that determines a cable status. A test module transmits a test pulse on the cable, measures reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A first digital signal processor (DSP) communicates with a first pair of the cable and includes a first echo canceller having a finite impulse response (FIR) filter with taps and a first crosstalk canceller having a FIR filter with taps. A second DSP communicates with a second pair of the cable and includes a second echo canceller having a FIR filter with taps and a second crosstalk canceller having a FIR filter with taps. The cable tester calculates a distance to at least one of echo and crosstalk based on values of the taps of the first echo canceller and the second crosstalk canceller.

Abstract: A physical layer device communicates over a cable and includes a cable tester that determines a cable status. The cable tester includes a pretest module that senses activity on the cable. A test module transmits a test pulse on the cable, measures reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A first digital signal processor (DSP) communicates with a first pair of the cable and includes a first echo canceller and a first finite impulse response filter with first taps. A second DSP communicates with a second pair of the cable and includes a second echo canceller and a second finite impulse response filter with second taps. At least one of the physical layer device and the cable tester estimates skew between the first and second pairs based on values of the first and second taps.

Abstract: A physical layer device is adapted to communicate with a cable medium and communicates with an indicator. The physical layer device includes a first input/output terminal, a first transceiver that communicates with the first input/output terminal that is adapted to be connected to a cable medium, and a cable tester that tests the cable medium and determines a cable status using a pretest module. The pretest module senses activity on the cable medium and enables testing if activity is not detected for a first period, and a test module that is enabled by said pretest module, transmits a test pilse on the cable medium, measures a reflection amplitude and calculates a cable length. The cable tester determines the cable status based on the measured amplitude and the calculated cable length, and the indicator indicates at least one of cable testing status during the test and the cable status after the trst.

Abstract: A propagation delay time of a cable assembly is measured by calculating a half of a time difference between a branch point of time-dependent variations of amplitude of reflection coefficient obtained by connecting a first connector with both terminals open-circuited and a second connector with one terminal short-circuited to a conversion adaptor in turn and a branch point of the time-dependent variations of the amplitude of reflection coefficient obtained by connecting one terminal of the cable assembly with other terminal connected to the first connector and one terminal of the cable assembly with other terminal connected to the second connector to the conversion adaptor in turn.

Abstract: A physical layer device is provided that includes an autonegotiation circuit that negotiates a link with a link partner at first and second link speeds. The physical layer device also includes a cable tester that tests a cable and that determines a cable status of the cable before autonegotiation circuit negotiates the link at the first and second link speeds.