WO2004091105A2 - Appareil et procede permettant de tester le parcours d'un signal a partir d'un point d'injection - Google Patents

Appareil et procede permettant de tester le parcours d'un signal a partir d'un point d'injection Download PDF

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Publication number
WO2004091105A2
WO2004091105A2 PCT/US2004/010127 US2004010127W WO2004091105A2 WO 2004091105 A2 WO2004091105 A2 WO 2004091105A2 US 2004010127 W US2004010127 W US 2004010127W WO 2004091105 A2 WO2004091105 A2 WO 2004091105A2
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WO
WIPO (PCT)
Prior art keywords
signal
signal path
autocorrelation
path
frequency
Prior art date
Application number
PCT/US2004/010127
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English (en)
Other versions
WO2004091105A3 (fr
Inventor
Cynthia Furse
Chet Lo
You Chung Chung
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University Of Utah Research Foundation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from PCT/US2003/037233 external-priority patent/WO2004046652A2/fr
Application filed by University Of Utah Research Foundation filed Critical University Of Utah Research Foundation
Publication of WO2004091105A2 publication Critical patent/WO2004091105A2/fr
Priority to US11/241,757 priority Critical patent/US7215126B2/en
Publication of WO2004091105A3 publication Critical patent/WO2004091105A3/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/11—Locating faults in cables, transmission lines, or networks using pulse reflection methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
    • G01R31/2832—Specific tests of electronic circuits not provided for elsewhere
    • G01R31/2836—Fault-finding or characterising
    • G01R31/2839—Fault-finding or characterising using signal generators, power supplies or circuit analysers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/58—Testing of lines, cables or conductors

Definitions

  • the present invention relates generally to the field of electronic system testing. More particularly, the present invention relates to methods and apparatuses for testing the signal paths in electronic systems.
  • Related Art
  • TDR Time Delay Reflectometry
  • FDR Frequency Domain Reflectometry
  • SWR Standing Wave Reflectometry
  • TDR Time Delay Reflectometry
  • FDR Frequency Domain Reflectometry
  • SWR Standing Wave Reflectometry
  • FDR requires two connections to the signal path being tested, most typically implemented by use of directional couplers, allowing the separation of the injected test signal from the reflected signal. These directional couplers are bulky and expensive. Directional couplers are also limited in frequency range, which limits the type of test signals that can be injected. [004] Although SWR can be used without directional couplers, SWR is typically limited to providing a pass/fail characterization of the signal path. In SWR techniques, the frequency spacing at which the reflected signal reaches minimums is determined to obtain a rough estimate of the location of a problem. SWR does not perform well when there are multiple problems in the signal path. Isolation of the actual location of the problem along the signal path is difficult to determine accurately with FDR or SWR.
  • TDR techniques avoid the problem o'f requiring two connections by injecting a time-limited pulse as the test signal. Confusion between the test signal and reflected signal is thus avoided because they are separated in time.
  • TDR eliminates the complexity associated with the directional couplers, TDR suffers from requiring very precise timing. The accuracy with which TDR can locate a problem is limited by the accuracy by which the time-limited test pulse can be generated and the accuracy that the reflected signal can be measured. Hence, accurate TDR systems require complex and expensive timing circuitry.
  • TDR cannot be used with signal paths that are designed to support a narrow range of frequencies because the TDR pulse is a wide-bandwidth signal.
  • the invention includes an apparatus for testing a signal path.
  • the apparatus may include a signal generator configured to inject a test signal into the signal path at an injection point.
  • the apparatus may further include a detector coupled to the signal generator. The detector may be configured to receive a combined signal at the injection point and determine an autocorrelation of the combined signal .
  • the combined signal may include the superposition of the test signal and reflections of the test signal from the signal path.
  • the apparatus may further include an analyzer coupled to the detector. The analyzer may be configured to determine a characteristic of the signal path from the autocorrelation.
  • the apparatus can be used to characterize a signal path, including determining the length of the signal path, impedance of the signal path, presence of faults in the signal path, location of faults in the signal path, and location of junctions in the signal path.
  • Various types of signal paths may be characterized, including wires, twisted pairs, multi-conductor cables, coaxial cables, transmission lines, waveguides, and wireless paths.
  • the invention can provide reduced component cost relative to TDR technology, since high accuracy timing components and directional couplers are not required.
  • the invention can also provide improved accuracy relative to SWR technology.
  • FIG. 1 is a block diagram of an apparatus for testing an electronic signal path in accordance with an embodiment of the present invention
  • FIG. 2 illustrates an example of the autocorrelation for three signal path examples compared to a result obtained using a frequency domain reflectometry technique
  • FIG. 3 is a circuit diagram of a mixed signal reflectometer in accordance with an embodiment of the present invention
  • FIG. 4 is a block diagram of an implementation of a detector in accordance with an embodiment of the present invention.
  • FIG. 5 is a block diagram of another implementation of a detector in accordance with an embodiment of the present invention.
  • FIG. 6 is a block diagram of a system having integrated signal path testing in accordance with an embodiment of the present invention.
  • FIG. 7 is example estimated spectrum of the autocorrelation estimated with a Fast Fourier Transform in accordance with an embodiment of the present invention
  • FIG. 8 is an example estimated wire length characteristic of a signal path estimated' in accordance with an embodiment of the present invention.
  • FIG. 9 is a flow chart of a method for detecting faults in a signal path in accordance with an embodiment of the present invention.
  • FIG. 10 is an illustration of an a,fter-market add-on mixed signal reflectometer in accordance with an embodiment of the present invention
  • FIG. 11 is a side view of the after-market add-on mixed signal reflectometer of FIG. 10;
  • FIG. 12 is a block diagram of a simulation of a spread-spectrum mixed signal reflectometer in accordance with an embodiment of the present invention
  • FIG. 13 is a timing diagram showing the operation of the spread- pectrum mixed signal reflectometer of FIG. 12 over a first time interval
  • FIG. 14 is a timing diagram showing the operation of the spread-spectrum mixed signal reflectometer of FIG. 12 over a second time interval
  • FIG. 15 is a block diagram of a mixed signal reflectometer within an enclosure in accordance with an embodiment of the present invention.
  • FIG. 1 illustrates a block diagram of an apparatus for testing the integrity of a signal path, in accordance with an embodiment of the present invention.
  • the apparatus referred to as a Mixed Signal Reflectometer (MSR)
  • MSR Mixed Signal Reflectometer
  • the MSR 100 may include a signal generator 102 configured to inject a test signal 108 into the signal path 114 at an injection point 116 when coupled to the signal path.
  • the MSR may further include a detector 104 coupled to the signal generator and configured to receive a combined signal 112 at the injection point when coupled to the signal path and configured to determine an autocorrelation of the combined signal.
  • the combined signal includes the superposition of the test signal and reflections 110 of the test signal from the signal path, as discussed further below.
  • the MSR may further include an analyzer 106 coupled to the detector and configured to determine a characteristic of the signal path from the • autocorrelation.
  • Reflections of the test signal from the signal path may be generated when impedance discontinuities are present in the signal path, including, for example, an open circuit, short circuit, mismatched termination, junction, etc. Depending on the number and magnitude of the impedance discontinuities, the number and amplitude of reflections will vary. For example, for a signal path terminated in its characteristic impedance, no measurable reflection may be observed; for a signal path with many junctions, numerous reflections may be observed. [029] Because the test signal 108 and reflected signal 110 are not separated from each other in time, as in TDR techniques, or physically separated ( e . g.
  • the reflected signal 110 is superimposed upon the test signal 108, producing a combined signal 112.
  • the combined signal will demonstrate unique characteristics in phase and amplitude as a function of the frequency of the test signal as discussed further below.
  • the detector converts these unique phase and amplitude characteristics into an autocorrelation.
  • the autocorrelation can then be analyzed by the analyzer to extract characteristics of the signal path.
  • the MSR provides several advantages over FDR, TDR, and SWR techniques. For example, the autocorrelation is approximately constant for particular test signal frequency, hence the detector and analyzer need not operate with precise timing as is required for TDR.
  • the autocorrelation produced by the detector provides sharper peaks and nulls than conventional SWR enabling more accurate location of impedance discontinuities in the signal path.
  • ⁇ the signal generator 102 may generate a test signal 108 which is a sine wave with a frequency ⁇ .
  • the test signal is thus given by: sin( ⁇ t) .
  • the injected test signal and reflected superimposed signals thus superimpose to form the combined signal : sin(ot) + ⁇ sin( ⁇ »t+6>) (3) which is the input to the detector 104.
  • the detector 104 determines the autocorrelation of the combined signal.
  • the detector may be, implemented in a variety of ways, including for example, and not by way of limitation, a square law device and low frequency extractor. Considering the example of -a square law device and DC extractor, the detector first forms the square of the combined signal 112:
  • FIG. 2 illustrates an example of the autocorrelation for three signal path examples (labeled MSR) compared to a result obtained using a frequency domain reflectometry technique (labeled FDR) .
  • the top trace shows an example where the signal path is a wire of length- 91.4 cm, the center trace a wire of length 457.2 cm, and the bottom trace a wire of 711.2 cm.
  • the results have been normalized to a maximum of 1 for illustration purposes.
  • the results in FIG. 2 were obtained using the MSR circuit of FIG. 3 discussed further below.
  • the variation in the autocorrelation as a function of frequency is approximately as predicted by equation (11) .
  • the signal generator may be implemented using a VCO, for example, as described above.
  • the signal generator may also be implemented using a frequency synthesizer.
  • the signal generator may be implemented using several VCOs, where each VCO tunes a different range of frequencies.
  • the resulting test signal may thus take on a variety of forms, including a swept-frequency sine wave, a multi-component wave (i.e., a sum of multiple sine waves of different frequencies), and a stepped-frequency sine wave.
  • the test signal may even take the form of an arbitrary signal as will now be explained.
  • f i t which is square integrable, its autocorrelation function is defined as
  • the autocorrelation of the scaled signal is a function of both the scaling factor, a, and the delay ⁇ .
  • the signal generator 102 may generate an arbitrary function g i t) .
  • the combined signal is then given by g i t) + ⁇ g i t- ⁇ ) (18) where ⁇ is the round trip propagation delay from the injection point to the impedance discontinuity causing the reflection and back to the injection point.
  • ⁇ is the round trip propagation delay from the injection point to the impedance discontinuity causing the reflection and back to the injection point.
  • Low pass filtering may be performed by integration, to yield the autocorrelation
  • the signal generator may be configured to generate a multi-frequency sine wave, a band limited-pulse, a spread-spectrum signal, or a noise-like signal.
  • different waveforms may prove beneficial.
  • a band-limited pulse may be more compatible than the wide-bandwidth pulses required by TDR.
  • Spread-spectrum or noise-like signals may permit testing while the signal path has an operational signal present.
  • PCT Patent Application Serial No. PCT/US/04/03343 attorney docket 22760.
  • PCT PCT
  • PCT Patent Application Serial No. (attorney docket 21724. PCT) entitled Method and System for Testing a Signal Path Having an Operational Signal, filed March 17, 2004, which is herein incorporated by reference for all purposes.
  • a Spread Spectrum Mixed Signal Reflectometer combines the principles of the MSR 100 discussed above and a Spread
  • FIG. 12 illustrates a Matlab_ Simulink simulation of a SSMSR.
  • the PN code generator 1202 produces a PN sequence output D i t)
  • the VCO 1204 outputs a carrier signal sin( ⁇ t) .
  • product 1206 multiplied together by product 1206 to produce a spread-spectrum signal.
  • the spread-spectrum signal is applied to the simulated channel 1208.
  • the combined signal 1210 from the simulated channel will be given by:
  • the output of Product 1 will be: cos ( ⁇ ( ⁇ ) ) -cos (2 ⁇ t+ ⁇ ( ⁇ ) ) (31) which will result in a larger value which- indicates a match between the Variable Transport Delayl and the delay in the signal path.
  • the output from the Sample and Holdl 1224 will have a value proportional to cos(f9( ⁇ )) .
  • the output of the Sample and Holdl will trace out a sinusoidal function of a frequency related to the delay value of the signal path.
  • the detector includes Products 1212 and Low Pass Filter 1220.
  • the spread-spectrum correlator includes
  • an MSR 100 may further include a correlator configured to correlate the square with a delayed version of the test signal and output a correlated signal to the low-frequency extractor wherein the signal generator is configured to produce a spread- spectrum signal.
  • FIG. 13 and FIG. 14 illustrate a trace of the outputs from the Sample and Holdl, Integratorl, and Variable Transport Delayl 1216.
  • the detector may be implemented using a square law device 402 and a low frequency extractor 404, for example as described above, and as illustrated in FIG. 4 in accordance with an embodiment of the present invention.
  • square law devices are known in the art, including, and not by way of limitation, a mixer, exponential amplifier, multiplier, ' or a non-linear function.
  • the square law device may be implemented using a mixer 312, wherein mixing inputs of the mixer are configured to receive the combined signal and the output of the mixer produces the square of the combined signal, as illustrated in FIG. 3 in accordance with an embodiment of the present invention.
  • the square law device may be implemented by using an envelope detector 502 followed by a squaring device 504 as illustrated in FIG. 5 in accordance with an embodiment of the present invention.
  • Various other implementations of the detector will occur to one of skill in the art and in possession of this disclosure and are to be considered within the scope of the present invention.
  • the low frequency extractor 404 may be implemented using a low pass filter, an integrating amplifier, a summing amplifier, or a summation circuit. In general, any component with a limited frequency response may also provide this function. For example, an analog to digital converter
  • the analyzer 106 may be configured to determine various characteristics of the signal path, including, wire length, cable impedance, and distance to an impedance discontinuity.
  • the analyzer may determine the distance to an impedance discontinuity (e.g., one caused by a fault) by examining the variation of the detector output as a function of the test signal frequency ⁇ .
  • the detector output will vary from a maximum, where ⁇ - ⁇ _ ⁇ - 2k ⁇ (32) to a minimum, where ⁇ _ - ⁇ 2 ⁇ - 2 (Jfc + l ) ⁇ (33) where k is a positive integer.
  • the detector output will periodically vary between a minimum and maximum.
  • the distance to the fault, ⁇ may be determined by varying ⁇ and finding the distance between these extrema (minimums or maximums) , where ⁇ - ⁇ / i ⁇ z - ⁇ _) .
  • this distance is expressed in terms of a time delay. It frequently will be preferable to convert this distance into a length measurement by taking into account the propagation velocity in the signal path under test.
  • the analyzer 104 may be implemented by performing pattern matching against the expected detector output by injecting several different test values of ⁇ and performing a best fit estimate to determine ⁇ and ⁇ .
  • the signal generator may be configured to generate a number of discrete frequency sine waves as discussed above. Pattern matching may be performing by comparing the autocorrelation to an expected autocorrelation for a hypothesized signal path characteristic . [058] Pattern matching the autocorrelation may be performed based on the Cauchy-Schwartz Inequality, which provides that for two vectors, xand y,
  • the above algorithm may be used by the analyzer to estimate the frequency, phase, amplitude, and DC offset of an unknown sinusoidal function, such as the autocorrelation.
  • the estimation of A, ⁇ , ⁇ and d may be accomplished in two steps. First, for each given ⁇ , the optimal s is estimated. Second, with the optimal s " for each ⁇ , the finite set of ⁇ is searched to find the value of ⁇ that maximizes T Hs .
  • the optimal A, ⁇ and d may be determined for the given ⁇ .
  • the set of possible ⁇ may be searched to find that which maximizes x r Hs /
  • BEGIN x vector containing the autocorrelation with frequency, phase, amplitude, and DC offset to be determined
  • ⁇ search set of frequencies
  • t vector containing points in time s
  • ⁇ vector containing amplitude, phase, and DC offset information
  • r vector containing the fitness value for each frequency, for ⁇ e ⁇
  • the signal generator may be configured to generate signals in several different discrete frequency ranges. This may also prove beneficial for certain types of failures in a signal path, for example a fray or chafe which does not result in a complete open or short circuit. The characteristics of the fray or chafe may vary with the frequency of the test signal, making detection difficult or impossible for certain frequency ranges. By testing at several different frequencies, enhanced ability to detect a, failure may be obtained.
  • the analyzer may be configured to estimate a spectrum of the autocorrelator, for example using a Fast Fourier Transform (FFT), to determine these multiple periodicies.
  • FFT Fast Fourier Transform
  • the signal path may include a network of connections: multiple junctions and branches.
  • each junction may result in a reflection • (if there is an impedance discontinuity)
  • each branch may create its own reflections corresponding to its impedance discontinuities. These reflections propagate back to the injection point, resulting in a complex combined signal .
  • a system shown generally at 600, having integrated signal path testing may be implemented as illustrated in FIG. 6.
  • the system may include a plurality of signal paths 114 and system components 602, wherein a plurality of the signal paths include at least one MSR 100.
  • the MSR may include a signal generator, a detector, and an analyzer, as described above.
  • the autocorrelation results for the MSRs may be combined to allow the reduction of ambiguity. For example, the autocorrelation results may be communicated between the MSRs over the signal paths.
  • mapping the network may be attempted. Unambiguous determination of the network topology may, however, not always be possible. For example, a mapping technique disclosed by A. Tarantola in "The Seismic Inverse Problem, " Inverse Problems of
  • FIG. 3 illustrates a circuit diagram of an MSR in accordance with an embodiment of the present invention.
  • the MSR shown generally at 300, includes a signal generator 102, detector 104, and analyzer 106.
  • the signal generator is implemented- using a voltage controlled oscillator (VCO) 302 and digital to analog converter (DAC) 304.
  • VCO voltage controlled oscillator
  • DAC digital to analog converter
  • the VCO is implemented with a Minicircuits JTOS200.
  • the frequency of the VCO is controlled by a computer 306 through the DAC 304 as will be discussed further below.
  • the output of the signal generator is injected into the signal path 114. As discussed above, reflections from the signal path, for example, from the end of the wire, will superimpose on the injected signal to produce a combined signal.
  • the combined signal is detected by the detector.
  • the detector is implemented using
  • a Minicircuits LAT15 attenuator 310 is included to reduce the level of the combined signal to reduce the potential for overload of the mixer.
  • the mixer is connected so that the combined signal is fed into both the local oscillator (LO) and radio frequency (RF) input ports. Hence, the mixer performs a squaring operation on the combined signal.
  • the output from the mixer is fed to an analog to digital converter (ADC) 308.
  • ADC automatically filters out high frequency components, thus extracting the low-frequency (DC) components of the mixer output to produce. the autocorrelation .
  • the computer 306 is programmed to control the overall operation of the MSR.
  • the computer steps the VCO frequency from 100 to 200 MHz using 2048 steps of approximately 50 kHz each.
  • the computer holds the VCO frequency constant while the detector determines the autocorrelation.
  • the computer then reads the autocorrelation from the DAC.
  • the computer 308 is also programmed to implement the analyzer 106.
  • the computer records the 2048 autocorrelation values. As illustrated by equation (11), this set of readings will have a frequency that is linearly proportional to the wire length.
  • the computer takes the set of 2048 readings and performs a Fast Fourier Transform (FFT) to determine the spectrum of the autocorrelation.
  • FFT Fast Fourier Transform
  • the FFT result is illustrated in FIG. 7. As expected, the peak in the FFT corresponds to the predominant frequency observed in the autocorrelation, and corresponds to the wire length.
  • the decreased magnitude of the FFT peak for increasing wire lengths is due to the attenuation of the wire as discussed previously.
  • the length of the wire is estimated by the computer by finding the FFT bin frequency corresponding to the peak of the spectrum.
  • FIG. 8 illustrates the result for tests on a variety of wire lengths up to 800 cm. The results are accurate within 10 cm.
  • reflections may be created right at the injection point due to an impedance mismatch between the MSR and signal path. This will result in a constant DC offset in the autocorrelation corresponding to zero length peak.
  • This peak may be removed using various signal-processing techniques. For example, the DC offset may be estimated and removed before computing the FFT.
  • FIG. 9 illustrates a flow chart of a method for detecting faults in a signal path 900 in accordance with another embodiment of the present invention.
  • the method may include injecting 902 a test signal into the signal path at an injection point. Although this test signal is usually chosen to be a swept-frequency sine wave, 'a variety of other test signals may also be used consistent with method as discussed previously.
  • the method may further include receiving 904 a combined signal from the signal path at the injection point.
  • the combined signal includes the superposition of the test signal and reflections of the test signal from the signal path as discussed previously.
  • the method may further include determining 906 an autocorrelation of the combined signal. Various techniques for determining the autocorrelation have been discussed above. Finally, the method may further include estimating 908 a characteristic of the signal path from the autocorrelation. Various techniques for estimating a characteristic of the signal path have been discussed above. [082] Although this description has focussed mainly on the testing a signal path, there are numerous other applications for embodiments of the present invention. The following exemplary embodiments are among the many potential applications of the inventions disclosed herein. Of course, other applications of the MSR technology will be readily apparent to one of ordinary skill in the art.
  • a handheld meter can contain the MSR and may be attached to the signal path wiring through any ordinary junction point, e . g. , circuit breaker, connector, wiring integration unit and junction box. The user can test one wire alone or could test a set of wires.
  • FIG. 15 illustrates an MSR packaged within an enclosure 1502 which may be in the form of a handheld meter.
  • the enclosure may include a port 1504 for connection to a signal path.
  • the port 1504 may include a test lead for connection to the wiring.
  • a multiplexer or switch 1506 may be used to switch to each wire individually, and the handheld tester connected to multiple wires simultaneously using multiple ports 1508.
  • a circuit breaker is a commonly available junction point in a circuit.
  • the MSR may be integrated into existing or new circuit breakers, or otherwise placed within the circuit breaker panel.
  • the enclosure 1502 (FIG. '15) may take the form of a circuit breaker housing or circuit breaker panel .
  • the MSR can be used in conjunction with the circuit breaker, or can replace it, particularly if the MSR is configured_ to detect intermitted short circuits. For example, even if the signal path is not fully open or short-circuited and an intermittent arc occurs, a peak in the spectrum will appear corresponding to the location of the arc.
  • Several readings may be stored, and compared sequentially. The maximum differences between the average or median of the readings may be obtained.
  • Connector A connector associated with the wiring may contain the MSR electronics. Existing connectors may be replaced by MSR-enabled connectors, or a separate "connector-saver" that has male pins on one side and female sockets on the other, with the electronics included within the connector-saver . Then the existing connectors may be plugged into either side of this connector-saver . For example, see co-pending U.S. Patent Application Serial No.
  • the connector may connect to power within the bundle being tested.
  • the connector may include a battery (possibly rechargeable) .
  • the connector may scavenge power from the aircraft surroundings using vibration, thermal changes, or other well-known power scavenging methods.
  • each connector may include a communication interface to get the data back to a central location for examination by a maintenance technician, pilot, remote decision-making interface, or the like.
  • each connector may include a communication link that is either hard-wired or wireless, e . g. , RF, IR, etc.
  • the connector may be suitable for visual examination, for example by including a set of light emitting diode indicator outputs, or a hard-wired or wireless connection between a handheld PDA. If there are more than two wires within the bundle, the connector may include a multiplexer or set of switches to test each of the wires separately. Alternatively, several systems may be built into a single chip, embedded into the connector and configured to test the set of several wires simultaneously. [087] Junction Box or Panel .
  • the MSR may be integrated into a junction box or panel. Such boxes, often called wiring integration units, may provide a convenient location for integrating the MSR into an existing electronic system. [088] Integrated testing.
  • the MSR may be integrated into a new electronic system by including the MSR electronics within components, circuit boards, or sub-assemblies of the system.
  • Wiring It has been contemplated that as the electronics for the MSR are reduced in size by manufacturing improvements and miniaturization, that the MSR may be imbedded directly within a roll of wiring. Multiple or single MSR units may be included within a roll of wiring. This application is particularly appealing for new types of wires that are being examined that are extruded and could be connected onto small circuit boards rather than the traditional connectors or for wires that are built on rolls of high-impedance plastic. These are the same materials, in some cases, that flexible circuit boards can be built on and, thus, that the MSR can be attached to.
  • Wireless Ranging Another embodiment for the disclosed MSR technology is ranging, i.e., finding the distance.
  • the MSR technology can be used for determining a distance between two wireless transmitters or for ranging in radar or other wireless applications.
  • the signal path is a wireless propagation path, and the operation is as described above.
  • improved dynamic range in the detector may be obtained by performing a long integration or summation.
  • the MSR technology can be used to determine the height of materials, e . g. , grains/granular materials, water/fluids, etc., by- measuring the length and multiple reflections on a wire imbedded in the material. Furthermore, the MSR technology may also be used to determine the electrical properties of materials and, thus, physical parameters such as moisture, salinity, fat/water content, etc.
  • MSR technology may be implemented as an add-on circuit to be used in conjunction with an existing handheld multimeter to find faults or measure the length of a wire. This approach results in lower parts count and power requirements than a fully integrated MSR testing system, and provides a small, conveniently used and transported addition to a technician's test equipment .
  • An integrated assembly combines the MSR technology, a battery or other power source, test leads, and a connection to an existing multimeter as illustrated in
  • the MSR add-on circuit 1000 can be snapped into the sockets of the existing multimeter 1002, or connected via leads to the sockets of the existing multimeter.
  • the MSR add-on may include plugs 1004 (shown in side view FIG. 11) configured to plug directly into the existing multimeter.
  • the leads of the MSR add-on may be integral to the add-on, or the MSR add-on may include jacks 1006 for insertion of test leads.
  • the leads of the MSR add-on circuit can be connected to the wire under test.
  • the MSR add-on determines the distance to a fault or the length of the wire, and converts this to a voltage that is output to the multimeter.
  • a voltage of 3.2 V may be output to indicate a distance of 3.2 meters, and positive or negative voltages, may be used to indicate a short or open circuit.
  • the MSR addon may include an integrated display 1008 which displays the result directly.

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  • Measurement Of Resistance Or Impedance (AREA)

Abstract

La présente invention concerne un appareil et un procédé permettant de tester un parcours de signal. L'appareil précité comprend un générateur de signaux (102) configuré pour injecter un signal de test dans le parcours de signal à un point d'injection lorsqu'il est couplé audit parcours. L'appareil comprend également un détecteur (104) couplé au générateur de signaux et configuré pour recevoir un signal combiné au point d'injection lorsqu'il est couplé au parcours de signal et pour déterminer une autocorrélation du signal combiné. L'appareil de l'invention comprend en outre un analyseur couplé au détecteur et configuré pour déterminer une caractéristique du parcours de signal à partir de l'autocorrélation. Le procédé de l'invention consiste à injecter (902) un signal de test dans le parcours de signal à un point d'injection, à recevoir (904) un signal combiné en provenance du parcours de signal au point d'injection, à déterminer (906) une autocorrélation du signal combiné, et à estimer (908) une caractéristique du parcours de signal à partir de l'autocorrélation.
PCT/US2004/010127 2002-11-19 2004-03-31 Appareil et procede permettant de tester le parcours d'un signal a partir d'un point d'injection WO2004091105A2 (fr)

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US45948203P 2003-03-31 2003-03-31
US60/459,482 2003-03-31
USPCT/US03/37233 2003-11-19
PCT/US2003/037233 WO2004046652A2 (fr) 2002-11-19 2003-11-19 Dispositif et procede de detection d'anomalies dans un cable

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US11/133,145 Continuation-In-Part US7495450B2 (en) 2002-11-19 2005-05-18 Device and method for detecting anomolies in a wire and related sensing methods

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Publication number Priority date Publication date Assignee Title
EP2137830A1 (fr) * 2007-03-23 2009-12-30 QUALCOMM Incorporated Réduction de la distorsion de second ordre provoquée par une fuite de signaux de transmission
WO2010140945A1 (fr) * 2009-06-04 2010-12-09 Telefonaktiebolaget L M Ericsson (Publ) Selt passif
WO2011053212A3 (fr) * 2009-10-30 2012-07-26 Telefonaktiebolaget L M Ericsson (Publ) Agencement et procédé concernant l'analyse de lignes de transmission
WO2020084408A1 (fr) * 2018-10-22 2020-04-30 Dac System Sa Système de détection de défaillance pour lignes de transmission coaxiales

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US4980844A (en) * 1988-05-27 1990-12-25 Victor Demjanenko Method and apparatus for diagnosing the state of a machine
US5600660A (en) * 1992-02-21 1997-02-04 Siemens Aktiengesellschaft Method for determining the number of defective digital bits (defective bit number) transmitted over a data-transmission path to be tested, and device for the carrying out of the method
US6654105B2 (en) * 2000-03-06 2003-11-25 Corning Applied Technologies Corporation Cross-correlating PMD detector

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US4110572A (en) * 1976-06-08 1978-08-29 The Post Office Method and apparatus for testing transmission lines
US4980844A (en) * 1988-05-27 1990-12-25 Victor Demjanenko Method and apparatus for diagnosing the state of a machine
US5600660A (en) * 1992-02-21 1997-02-04 Siemens Aktiengesellschaft Method for determining the number of defective digital bits (defective bit number) transmitted over a data-transmission path to be tested, and device for the carrying out of the method
US6654105B2 (en) * 2000-03-06 2003-11-25 Corning Applied Technologies Corporation Cross-correlating PMD detector

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2137830A1 (fr) * 2007-03-23 2009-12-30 QUALCOMM Incorporated Réduction de la distorsion de second ordre provoquée par une fuite de signaux de transmission
WO2010140945A1 (fr) * 2009-06-04 2010-12-09 Telefonaktiebolaget L M Ericsson (Publ) Selt passif
US8705636B2 (en) 2009-06-04 2014-04-22 Telefonaktiebolaget L M Ericsson (Publ) Passive single-ended line test
WO2011053212A3 (fr) * 2009-10-30 2012-07-26 Telefonaktiebolaget L M Ericsson (Publ) Agencement et procédé concernant l'analyse de lignes de transmission
US9009017B2 (en) 2009-10-30 2015-04-14 Telefonaktiebolaget Lm Ericsson (Publ) Arrangement and method relating to analysis of transmission lines
WO2020084408A1 (fr) * 2018-10-22 2020-04-30 Dac System Sa Système de détection de défaillance pour lignes de transmission coaxiales
CN113169758A (zh) * 2018-10-22 2021-07-23 直接天线控制系统有限公司 用于同轴传输线的故障检测系统

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