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400 results about "Time-domain reflectometer" patented technology
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A time-domain reflectometer (TDR) is an electronic instrument used to determine the characteristics of electrical lines by observing reflected waveforms. It can be used to characterize and locate faults in metallic cables (for example, twisted pair wire or coaxial cable). It can also be used to locate discontinuities in a connector, printed circuit board, or any other electrical path.
Detecting a linear impairment in a cable under test by using a random signal transmitted down the cable. The impairment causes a reflected signal to be combined with the random signal. The combined signal extends over a plurality of sub-bands. A method and apparatus perform the steps of: (a) receiving the combined signal from a test point upstream from the impairment; (b) tuning to each sub-band and receiving a part of the combined signal within each sub-band; (c) determining an autocorrelation function of each part of the combined signal of each sub-band, to produce a plurality of autocorrelation functions; (d) combining the autocorrelation functions to form a combined function; (e) detecting the reflected signal from the combined function; and (f) determining, from the combined function, a time delay associated with the reflected signal and the distance from the test point to the impairment.
The present invention provides a system for determining downhole conditions including a time domain reflectometer (172) that is operable to generate a transmission signal and receive a reflected signal. A tubular (192) is positioned downhole in a downhole medium (214, 216, 218, 220, 222) and a waveguide (186), which is in electrical communication with the time domain reflectometer (172), is operably contacting the downhole (214, 216, 218, 220, 222). The waveguide (186) is operable to propagate the transmission signal and operable to propagate the reflected signal that is generated responsive to an electromagnetic property of the downhole medium (214, 216, 218, 220, 222).
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 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 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 domainreflectometry testing on the terminated network cable.
An adaptive pulse width (APW) Time Domain Reflectometer (TDR) comprises an enhancement to the standard Pulse TDR by adjusting the effective pulse width as a function of time. Improved resolution for a large range of cable lengths is obtained, as well as allowing an all-in-one view of the processed return signal trace.
Optical Time-Domain Reflectometer (OTDR) troubleshooting of a passive optical network (PON) can be enhanced by deploying cascaded splitters, at least some of which have multiple inputs. That is, at least some of the splitters in the PON have not only a first input coupleable to the optical line terminator (OLT) or output of another splitter but also a second input directly coupleable to an Optical Time-Domain Reflectometer (OTDR). Optical time-delayreflectometry can be performed upon a selected portion or segment of the PON by selecting a splitter and transmitting an optical testsignal from the OTDR directly to the input of the selected splitter and analyzing the reflected signal.
A TDR for locating impairments in an HFC network is claimed. The network carries burst signals in an upstream band during burst intervals. The TDR comprises a transmitter, receiver, level detector, controller, accumulator, and probe detector. The transmitter transmits probe signals to the impairment, causing a reflection of the probe signals. Each probe signal is in the upstream band and has a bandwidth extending the width of the upstream band. The receiver receives the reflected probe signals during receiving intervals, and receives the burst signals during receiving intervals that overlap burst intervals. The level detector measures a level of the signals received during each receiving interval. The controller determines which of the receiving intervals are free of burst signals, based on the level measurement. The accumulator accumulates reflected probe signals received during intervals free of burst signals. The probe detector detects the impairment from the accumulated probe signals and estimates a time delay for the impairment. A distance to the impairment is estimated from the time delay.
Methods and systems for high-bandwidth time domainreflectometry include a printed circuit board (PCB) and a probe. The PCB includes at least one signal terminal connected to at least one signal via at least three guide terminals arranged around the at least one high-frequency signal terminal. At least one of the guide terminals is connected to at least one ground via. The probe includes at least one biased pin to contact the at least one signal terminal and at least three fixed guide pins arranged about the at least one biased pin to facilitate alignment of said at least one biased pin by first engaging at least one guide terminal area, such that the at least one mechanically biased pin is guided to the at least one contact point.
The present invention provides a time domain reflectometer for testing an electrical cable. The time domain reflectometer includes a test signal generator, at least one line feed resistor, connected between the test signal generator and a pair of terminals, for connection to the ends of the electrical cable under test, and a signal processor, connected to the terminals, to receive a line signal including a reflection of a test signal transmitted into the cable under test. The signal processor is programmed to filter the line signal to enhance a portion of the signal indicative of any fault on the cable by balancing the signal according to the electrical characteristics of a normal cable of the same type as the cable under test by applying a filter function, and acquiring at least one estimate of the input admittance of the transmission line from known or estimated electrical characteristics of the cable under test.
TDR (time domain reflection) technology may be used in optical domain or in electrical domain. For electrical TDR, single layer ITO glass may form a transmission line as a base TDR touch sensor. When the touch sensor is paired, the existing internal metal line of the display device may be reused as a TDR sensor and the ITO glass may be removed. When touched, the TDR profile is changed dynamically from baseline to the particular profile due to its dynamic impedance profile change across the display screen. Likewise, for optical TDR touch sensing, 2 dimensional optical slab waveguide is used to carry OTDR signal. When touched, the profile is changed due to this perturbation mainly by evanescent field changes on that particular position.
The present invention provides a system for determining downhole conditions including a time domain reflectometer (172) that is operable to generate a transmission signal and receive a reflected signal. A tubular (192) is positioned downhole in a downhole medium (214, 216, 218, 220, 222) and a waveguide (186), which is in electrical communication with the time domain reflectometer (172), is operably contacting the downhole (214, 216, 218, 220, 222). The waveguide (186) is operable to propagate the transmission signal and operable to propagate the reflected signal that is generated responsive to an electromagnetic property of the downhole medium (214, 216, 218, 220, 222).
A novel mechanism for performing high accuracy cable diagnostics. The mechanism utilizes time domainreflectometry (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 method for generating a broadbandchaoticsignal similar to white noise comprises the steps that beat frequency is carried out on two paths of chaotic lasers through an optical fiber coupler, the two paths of chaotic lasers are divided into two paths with the equal intensity, balanced detection is carried out on the two paths of optical signals, and a difference value signal is extracted and converted into a corresponding electric signal. A device for generating the broadband chaotic signal similar to the white noise comprises two chaotic laser emission devices, the optical fiber coupler and a balance detector. The optical frequencies of the chaotic laser emission devices are not equal, and an optical frequency difference is the spectral line width of the chaotic lasers. The chaotic signal generated through the method has the wide and flat frequency spectrum similar to that of the white noise, no rectilinear oscillation exists on the frequency spectrum, and periodicity caused when the chaotic lasers are generated through a time delaysystem can be thoroughly eliminated; the security of chaotic communication, the measurement accuracy of a radar and an optical time domain reflector, and the randomness of physical random numbers are improved. The method and device can be applied to the fields of communication, remote sensing, sensing and the like.
The invention provides a method of a multifrequency probe light time division multiplexing coherent light time domain reflectometer. The method is characterized in that: a detection light pulse being injected into a fiber being detected is multifrequency detection light pulse which generates time division multiplexing by utilizing sequential electric signal synchronization control phase modulator and light pulse modulator modulation; local oscillator light is single-frequency light, and power spectrum of the multifrequency detection light pulse is bilaterally symmetrical relative to local oscillator light frequency; 0 order frequency of the multifrequency detection light pulse is same with the local oscillator light frequency; modulation depth of the phase modulator is larger than 1; a backward scattering and / or reflection signal which the multifrequency light pulse of time division multiplexing is in mixes with the local oscillator light in a coherent detection module, both side are coherent and an intermediate frequencysignal of time division multiplexing is output by a photoelectric detector; an intermediate frequencysignalprocessing module amplifies an intermediate frequency signal of time division multiplexing detected by coherent detection, according to a characteristic of the intermediate frequency signal, a needed band pass filter is selected, the intermediate frequency signal is filtered, a subsequent circuit carries out real-time processing on a plurality of paths of intermediate frequency signals, and information of the fiber being detected is displayed.
Systems and methods for characterizing an optical fiber performed in part by an optical node in an optical line system include performing one or more measurements to characterize the optical fiber with one or more components at the optical node, wherein the one or more components perform functions during operation of the optical node and are reconfigured to perform the one or measurements independent of the functions; and configuring the optical node for communication over the optical fiber based on the one or more measurements. The one or more components can include any of an Optical Service Channel (OSC), an Optical Time Domain Reflectometer (OTDR), and an optical amplifier. The configuring can include setting a launch power into the optical fiber based on the one or more measurements.
The invention comprises, inter alia, a portable and easy to use tester for troubleshooting and determining the location of wiring intermittence shorts and wiring intermittence opens. The tester can also check the wire ability to carry a load and detect corrosion and bad contacts. Finally, the invention provides a method to apply the characteristics and qualities of a coaxial cable, to a regular, discrete, multi-wire harness. This method will improve the functionality of a conventional Time-Domain Reflectometer (TDR) system that typically can test only two wires at a time, connected to its input. By providing regular wires the characteristics and qualities of a coaxial cable this method will allow the creation of an expansion box that can interface to a conventional TDR system, and increase the number of wires it can test.
A dual wavelengthOptical Time Domain Reflectometer (OTDR) system, embedded in a network element, includes a first OTDR source for wavelength λ1; a second OTDR source for wavelength λ2; an OTDR measurement subsystem adapted to measure backscatter signals λ1_BACK, λ2_BACK associated with the wavelength λ1 and the wavelength λ2; and one or more ports connecting the first OTDR source, the second OTDR source, and the OTDR measurement subsystem to one or more fiber pairs; wherein wavelength λ1 and wavelength λ2 are each outside of one or more signal bands with traffic-bearing channels, thereby enabling operation in-service with the traffic-bearing channels.
A method for detecting cracks in a carbon fiber bicycle frame using an embedded optical fiber is provided. Optical time-domain reflectometry is employed to detect cracks in a bicycle frame made of carbon fibers intertwining with a single-mode optical fiber. The single-mode optical fiber is thus embedded into the bicycle frame and consolidated with the carbon fibers during a manufacturing process of the bicycle frame. Integration of the single-mode optical fiber, which has a small diameter, low cost and lightweight, into the bicycle frame adds little to a production cost and weight of the bicycle frame. The optical fiber consolidated within the bicycle frame can be connected with an optical time-domain reflectometer for efficiently detecting twists or cracks of the carbon fibers in the bicycle frame, both as a quality check in the manufacturing process and as a safety check after the bicycle frame has been used for some time.
A light branching section applies a light pulse emitted in synchronism with a drive pulse (DP), to an optical fiber line path, and receives the light returning from the line path. An A / D converter performs equivalent sampling on the optical signal contained in the returning light, in synchronism with the sampling pulse (SP) of period T0. A measuring control circuit (MCC) generates DP a number (M) of times. The circuit generates N number of SPs every time it outputs DP. It outputs the SPs, at a time delayed by DELTAT that corresponds to 1 / M of the period T0. A clocksignal generation circuit outputs to the MCC a first clocksignal of a period T1 and a second clock signal of a period T2 different by DELTAt from the period T1. The MCC imparts a delay DELTAT to the SPs, on the basis of the DELTAt.
There is provided a bi-directional optical reflectometric method for characterizing an optical fiber link. The method comprises: performing a plurality of forward-direction light acquisitions from one end of the optical fiber link and performing a plurality of backward-direction light acquisitions from the opposite end, wherein each light acquisition is performed by propagating at least one test lightsignal corresponding to given spatial resolution and detecting corresponding return light so as to obtain a reflectometric trace representing backscattered and reflected light as a function of a distance on the optical fiber link, and wherein said plurality of forward-direction light acquisitions and said plurality of backward-direction light acquisitions are each performed with mutually different spatial resolutions; and deriving a value of at least one parameter characterizing an event along said optical fiber link at least using a forward-direction light acquisition and a backward-direction light acquisition performed with mutually different spatial resolutions.