790results about "Fault location by pulse reflection methods" patented technology

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.

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.

A physical layer module (PHY) of a network device includes a control module and a cable-test module. The control module selectively generates a cable-test enable signal to test a cable including four pairs of twisted wire. The cable-test module tests the cable based on the cable-test enable signal. The cable-test module transmits test signals on the four pairs at a first time and receives return signals. The cable-test module determines that the cable is not faulty when the return signals received on first and second pairs of the four pairs have an amplitude less than a first predetermined amplitude, and when the return signals received on third and fourth pairs of the four pairs have an amplitude greater than a second predetermined amplitude and are received substantially contemporaneously.

Methods, systems and computer program products for uniquely identifying communication lines in a network via time domain reflectometry (TDR) signatures are provided. A pulsed signal is sent into a communication line through a patch panel connector port and a reflection of the pulsed signal through the patch panel connector port is received to obtain a TDR signature for each communication line. The pulsed signal is sent and received by a controller operatively associated with the patch panel and / or by a network switch in communication with the patch panel. Connection changes and / or communication line faults at a network patch panel are detected by comparing current and stored TDR signatures.

Fault detection and power network quality monitoring are performed for a power line network using power line communications (“PLC”) signal transceiving and data processing capabilities. Power line signals are continuously received and processed to obtain signal data representative of power line network operating conditions that are expressed in the received power line signals. The harmonic content and noise signature of the signal data are evaluated with reference to known fault signature data and power line network topology properties for detecting and identifying the location of an existing or anticipated fault in the power line network and assessing power transmission quality of the network.

A fault detection apparatus according to an embodiment is provided with a measurement unit, a memory unit, a control unit, and a display unit. The measurement unit measures a first time period taken until a reflection signal reflected on a fault of a test apparatus is received after a first signal is transmitted to the test apparatus. The memory unit includes a CAD data unit having CAD data of the test apparatus, and a model data unit to store model data indicating a relation between the first time period and a predicted conduction distance of the first signal according to the CAD data. The control unit calculates a range of a test object selected in the test apparatus based on the CAD data, calculates the predicted conduction distance from the first time period based on the model data, and specifies a position of a fault of the test apparatus which is separated by the predicted conduction distance from the measurement unit in the range of the test object. The display unit displays the position of the fault in the CAD data.

Systems and methods which utilize spread spectrum sensing on live circuits to obtain information regarding a circuit under test are provided. In some embodiments S / SSTDR testing may be utilized to obtain R, L, C and Z measurements from circuit components. In yet further embodiments, these measurements may be utilized to monitor the output of sensors on a circuit.

The present invention relates to a radio communication apparatus for checking antenna interface connections of first antenna means of the radio communication apparatus, wherein a predetermined signal is transmitted at a frequency within a reception band of the first antenna means by using a second antenna means of the radio communication apparatus. The transmitted predetermined signal is received through the first antenna means to obtain a reception output which is compared with the predetermined signal. Thereby, a self-test option can be provided in the communication apparatus, e.g. mobile phone, so that no extra components are required during manufacturing and antenna operation can be continuously monitored during usage.

Classifying a portion of an electrical signal propagating through a conductor includes digitizing the electrical signal to provide a digitized signal, providing a plurality of stored digitized signals, wherein each stored digitized signal corresponds to a type of fault for the conductor, comparing the digitized signal to each of the stored digitized signals to determine a score therefore, if the score is less than a predetermined value for a particular one of the stored digitized signals, classifying the portion of the electrical signal as a fault corresponding to the particular one of the stored digitized signals, and, if none of the scores are less than the predetermined value, classifying the portion of the electrical signal as having no fault. Classifying a portion of an electrical signal may also include converting the digitized electrical signal to reflection coefficients.

A method of testing a probe card includes the step of positioning the probe card in a prober over a verification wafer that is placed on a stage. The probe card is brought in contact with a contact region on the verification wafer. The verification wafer includes a shorting plane surrounding the contact region. A test signal is sent through the verification wafer to the probe card. A response signal from the probe card is received and analyzed.

A physical layer device that communicates over a cable comprises a cable tester that determines a cable status, which includes an open status, a short status, and a normal status. The cable tester includes a pretest module that senses activity on the cable and selectively enables testing based on the sensed activity. A test module is enabled by the pretest 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. A return loss estimator communicates with the cable tester and estimates return loss of the cable based on gain parameters of the physical layer device.

An automated telephone line test system that is well suited for determining the location of faults within a telephone network. The telephone line test system uses time domain reflectometry to aid in locating the faults. The time domain reflectometry unit is connected through a switch in the network so that the time domain reflectometry unit can be connected to multiple lines without human intervention. Parameters of the time domain reflectometry signals are controlled so that reflections from the switch do not interfere with measurement of parameters on the faulty line.

A detector and a variable signal generator are coupled so that one or more specific changes in the output of the detector will cause a change in the characteristics of the generated signal. This change in signal characteristics is non-transient, the change remaining in effect until such time that another change in the detector output causes another change in the signal characteristic. The system can provide remote-end positive wire identification with no additional instrumentation at the remote end. When this invention is embodied in an already existing piece of test equipment, such as a multimeter or time domain reflectometer, there need be no additional hardware instrumentation at either end.

A non-intrusive, fully automated, variable Cable and impedance-based, multiplexed cable testing system is described that uses Time Domain Reflectometry techniques. The system can process more than one cable type, with varying characteristics, at any one time during which it confirms and processes both the characteristics of the cable type under test and any discontinuities encountered during its operational life due to the impedance variations defined and processed. Furthermore, the system provides an extensive range of Real-Time Diagnostic and Prognostic data together with accurate location and interpretation of any said data and or discontinuity including, but not limited to, the additional mapping of impedance variations along the length of the cable.

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.

A method for testing an installed wiring harness is provided. The method comprises providing a signal source testing module at a first node in the wiring harness and a measurement termination testing module at a second node in the wiring harness. A central management module for controlling the testing modules coordinates the testing modules to send testing signals for performing tests and recording test measurements of the installed wiring harness. The testing modules send the test measurements to the management module.

An Adaptive Vector Cancellation method which uses time domain data for an instrument connection to estimate magnitude, phase, and time position of a signal response such as NEXT or Return Loss associated with the connection. Based on the estimate of the amplitude and time of the connection response, a suitable full-bandwidth frequency response that corresponds to a point source of NEXT or Return Loss is determined. This calculated connector response is then scaled to an appropriate magnitude, phase and time shifted to the estimated position of the actual connection. The scaled / shifted response is then vectorially combined with the measured sweep data to suitably cancel the connection contribution to NEXT and / or Return Loss. Thus, the amount of NEXT or return loss existing in the user's patch cord is preserved, while the NEXT or return loss due to the instrument connection is suitably suppressed. Correction is done in the frequency domain, over the full bandwidth of the measured data.

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.

An apparatus and method for high-resolution reflectometry that operates simultaneously in both the time and frequency domains, utilizing time-frequency signal analysis and a chirp signal multiplied by a Gaussian time envelope. The Gaussian envelope provides time localization, while the chirp allows one to excite the system under test with a swept sinewave covering a frequency band of interest. High resolution in detection of the reflected signal is provided by a time-frequency cross correlation function. The high-accuracy localization of faults in a wire / cable can be achieved by measurement of time delay offset obtained from the frequency offset of the reflected signal. The apparatus enables one to execute an automated diagnostic procedure of a wire / cable under test by control of peripheral devices.

A distance to PIM measurement circuit is made using a device such as an AWS transceiver that has separate transmit and receive bands. With a typical AWS transceiver placed in close proximity to a PCS transceiver, the AWS device will include a band reject filter to eliminate interference from the PCS signals. The PIM measurement circuit includes two frequency sources F1 and F2 that are provided through a combiner for characterization of the PIM circuit. To enable distance determination, an FM measurement is created by using a offset sweep generator attached to one of the two frequency sources. To avoid frequencies blocked by the band reject filter, a desired harmonic of a test PIM harmonic signal is selected outside the band of the band reject filter. In one embodiment, a reference signal is provided by mixing a signal from an ×M multiplier connected to the F1 source with an ×N multiplier signal connected to the F2 source, the mixed output being filtered to select the desired harmonic reference signal to avoid the band reject filter. In another embodiment, a reference signal is created by generating all harmonics of the combined F1 and F2 signal using a series connected amplifier and clipping diodes with a filter again used to select the desired harmonic reference signal to avoid the band reject filter.

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.

A power line communication-based aircraft power distribution system may allow for both power line communication (PLC) technology and spread spectrum time domain reflectometry (SSTDR) technology to be utilized in aircraft power distribution systems to achieve key maintenance functions. Unlike conventional power distribution systems, which may, for example, use only SSTDR for fault detection, the present invention includes a hardware platform that may allow both the PLC and the SSTDR to be utilized in aircraft power distribution systems to achieve key maintenance functions, such as real time wire fault location, and cost and weight savings. Further, unlike conventional power distribution systems, which may only detect and locate damage in feeder conductor wire sections before the power is applied to the load, the power distribution system of the present invention may permit real time wire fault location.

A time domain reflectometer having a first impedance when in a first test mode and a second impedance when in a second test mode. The first impedance is substantially the same as the nominal characteristic impedance of a network link cable not connected to a network and the second impedance is substantially different from the impedance of a network link cable that is terminated into a network. A method for measuring the length of a terminated network cable includes the steps of determining that the network cable is terminated at a network, selecting a test mode suitable for testing the terminated network cable, and performing time domain reflectometry testing on the terminated network cable.

A cable tester includes a pretest module that senses activity on a cable and selectively enables testing depending upon the sensed activity. A test module is enabled by the pretest module, transmits test pulses on the cable, measures a refelction amplitude, calculates a cable length, and determines a cable status based on the measures amplitude and the calculated cable length. A polarity detector communicates with the cable tester and detects a polarity of at least one pair of the cable. The test module senses activity on a first pair of the cable, enables testing if activity is not detected for a first period, and enables testing of the first pair if, during the first period, activity is detected on the first pair and is subsequently not detected on the first pair for a second period after the activity is detected.

A device and method for measuring the electrical properties of electronic signal paths, including wires and wireless channels. The device may be used for detecting open circuits, short circuits, and the lengths of wires.

A method and system for performing sequence time domain reflectometry to determine the location of line anomalies in a communication channel is disclosed. In one embodiment, the system generates a sequence signal and transmits the sequence signal over a channel. The system receives one or more reflection signals, and performs reflection signal processing on the reflection. In one embodiment, the reflection signal is correlated with the original sequence signal to generate a correlated signal. The system determines a time value between the start of the reflection signal and the subsequent points of correlation to determine a location of a line anomaly. In one embodiment preprocessing and post-processing occurs to counter the effects of a communication device, such as a DMT modulator / demodulator. In one embodiment sampling of the sequence and reflection signal may occur at different times or at a different phase to provide greater resolution of the line anomaly location.

A PIM measurement circuit enables making forward and reverse PIM measurements on any 1 port (reflection) or 2 port (transmission) device with the ability to determine in distance where individual PIM impairments are located as well as their magnitude. The PIM measurement circuit includes two frequency sources that are provided through a combiner for a CW characterization of the PIM circuit. To enable distance determination, an FM measurement is created by using a saw tooth offset sweep generator attached to one of the two frequency sources. With downconversion and processing of signals from the PIM impairments, the FM signal provides a frequency variation that is converted using a Fourier transform or spectrum analysis for separation of frequencies, enabling determination of the distance of the PIM sources as well as their magnitudes.

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. In an exemplary embodiment, the disclosed method involves (i) connecting an alternating voltage source to a cable at a “sending end” thereof; (ii) applying a voltage to the cable at a first frequency to set up a traveling wave along the cable that is reflected at the “receiving end” thereof; (iii) permitting a standing wave pattern to be established along the cable by the traveling wave and the reflection thereof; (iv) measuring the total complex power loss (Sin) at the sending end of the cable; (v) calculating the standing wave voltage at any point / section of the cable based on the load impedance (ZL) connected at the receiving end of the cable, and the characteristic impedance (ZO) of the cable, or the measured / calculated cable parameters for the first frequency of the voltage source, (vi) repeating the foregoing steps while one of: (1) varying at least one of: the load impedance (ZL) connected at the receiving end of the cable, the first frequency of the voltage source; the output impedance of the voltage source, a combination of the load impedance (ZL), the output impedance of the voltage source and the first frequency of the voltage source, and combinations thereof; (2) interchanging sending and receiving cable ends; and (3) a combination thereof, and (vii) determining a dissipation factor (tan δ) and a dielectric constant (∈′), for the insulation, and an impedance, for the conductor at predetermined points / sections along the axis of the cable.