Noise intrusion position estimation device and noise intrusion position estimation method

Abstract

A noise intrusion position estimation device (100) comprises: a measuring unit (10) having a pair of detection units (11a, 11b) for simultaneously measuring the time variation of a noise waveform on a transmission cable (40) at two observation points separated from each other on the transmission cable (40); and a computing unit (30) for receiving the pair of noise waveforms measured simultaneously from the measuring unit (10), time-reversing the received pair of noise waveforms, using the two observation points as positions of a signal source of the time-reversed noise in a transmission line model (40S) reflecting the electrical characteristics of the transmission cable (40), performing a transmission path analysis using the time-reversed waveform as an excitation waveform, and outputting the position of a peak value obtained based on the result of the transmission path analysis as a position of noise intrusion into the transmission cable (40).

Description

Technical Field

[0001] The present invention relates to a noise intrusion position estimation device and a noise intrusion position estimation method, which, when noise is superimposed on a transmission cable, estimates from which position of the transmission cable the superimposed noise has intruded. Background Art

[0002] As a technique for estimating the noise intrusion position from the noise waveform instead of manually searching near the cable when searching for noise superimposed on the cable, Patent Document 1 discloses a noise detection method for detecting noise caused by partial discharge generated in a high-voltage power cable.

[0003] The noise detection method of Patent Document 1 calculates the noise mixing location and the noise intensity at the mixing location based on the noise intensity at the sensor position obtained from the signals detected by multiple sensors installed on the diagnosis target cable, the length of the cable between the sensors, and the attenuation rate of the noise when it propagates in the cable.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-133503 Summary of the invention

[0007] Problems to be solved by the invention

[0008] For noise caused by partial discharge generated in a high-voltage power cable, the noise mixing location and the noise intensity at the mixing location can be obtained based on the attenuation rate of the noise when it propagates in the cable.

[0009] However, in a transmission cable that propagates high-frequency signals, the noise waveform changes significantly due to the influence of multiple reflections or mode conversion in the transmission cable caused by different common-mode impedance distributions in the transmission cable. Therefore, it is difficult to estimate from which position of the transmission cable the superimposed noise enters based on the attenuation rate of the propagated noise.

[0010] Furthermore, in a transmission cable used for a balanced transmission path, it is also difficult to estimate a position where noise intruding in a common mode is converted into a differential mode, which is a normal mode, that is, an unbalanced position.

[0011] The present invention is made to solve the above-mentioned problems, and its object is to obtain a noise intrusion position estimation device that can estimate the intrusion position of high-frequency noise into a transmission cable when the high-frequency noise propagates in the transmission cable due to the influence of multiple reflections and mode conversion.

[0012] Means used to solve problems

[0013] The noise intrusion position estimation device of the present invention comprises: a measuring unit having a pair of paired detection units, the pair of paired detection units simultaneously measuring the time change of the noise waveform on the transmission cable at two separate observation points of the transmission cable having paired signal conductors; and a computing unit receiving the pair of paired noise waveforms measured simultaneously from the measuring unit, time-reversing the received pair of paired noise waveforms, taking the two observation points as the positions of the signal sources of the time-reversed noise in a transmission line model reflecting the electrical characteristics of the transmission cable, and performing the operation of using the time-reversed waveforms as excitation waves. A transmission path analysis of a certain shape is performed, and the position of the peak value in the mode voltage value obtained according to the result of the transmission path analysis is output as the intrusion position of noise into the transmission cable. The operation of the mode voltage value in the operation unit is to set the waveform after time reversal as a common mode waveform for calculating the voltage of 1 / 2 of the sum in one detection unit and the other detection unit of the paired detection units, and the intrusion position of the noise output by the operation unit is set as a common noise intrusion position, which is the position of the peak value in the common mode voltage value obtained according to the result of the transmission path analysis implemented by the common mode waveform.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to estimate the intrusion position of high-frequency noise propagating in a transmission cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a diagram showing the configuration of a noise intrusion position estimation device according to the first embodiment.

[0017] Figure 2 Schematic diagram showing a measurement method of the noise intrusion position estimation device according to the first embodiment.

[0018] Figure 3 This is a schematic diagram showing generation of a time-reversed signal of a noise waveform in a transmission cable of the noise-intrusion position estimation device according to the first embodiment.

[0019] Figure 4 This is a schematic diagram of voltage distribution calculation performed retroactively in time in the noise intrusion position estimation device according to the first embodiment.

[0020] Figure 5 This is a flowchart showing the operation of the calculation unit in the noise intrusion position estimation device according to the first embodiment.

[0021] Figure 6 It is a diagram showing the structure of a noise intrusion position estimation device according to the second embodiment.

[0022] Figure 7It is a schematic diagram showing a measurement method of the noise intrusion position estimation device according to the second embodiment.

[0023] Figure 8 This is a flowchart showing the operation of the calculation unit in the noise intrusion position estimation device according to the second embodiment. DETAILED DESCRIPTION

[0024] Implementation Method 1

[0025] use Figure 1 to Figure 5 , the noise intrusion position estimation device 100 according to the first embodiment is described.

[0026] The noise intrusion position estimation device 100 includes a measurement unit 10 , an analysis setting / model input unit 20 , and a calculation unit 30 .

[0027] The measuring unit 10 simultaneously measures the temporal change of the noise waveform superimposed on the transmission cable 40 to be measured at two separate observation points of the transmission cable 40 , namely, observation points at both ends of the transmission cable 40 in the first embodiment.

[0028] The transmission cable 40 has a signal conductor that propagates a high-frequency signal.

[0029] The measurement unit 10 includes a pair of sensors 11 a and 11 b , and a storage unit 12 .

[0030] The sensor 11a and the sensor 11b respectively detect the time change of the noise waveform superimposed on the transmission cable 40. The sensor 11a and the sensor 11b are detection units that simultaneously measure the time change of the noise waveform. In the first embodiment, a device for estimating the intrusion position of high-frequency noise into the transmission cable 40 composed of one signal conductor is shown.

[0031] When estimating the intrusion position of high frequency noise into the transmission cable 40 composed of a plurality of signal conductors, the measuring unit 10 includes a pair of sensors 11a and 11b for each of the plurality of signal conductors. For simplicity of description, the transmission cable 40 composed of a single signal conductor will be described below.

[0032] The sensor 11a and the sensor 11b have a probe 11a1 and a probe 11b1, respectively. Figure 2 As shown in FIG. 1 , the probe 11a1 of the first sensor 11a is connected to one end of the transmission cable 40, that is, to an observation point on one end side. Figure 2 As shown, the probe 11 b 1 of the second sensor 11 b is connected to the other end of the transmission cable 40 , that is, to the observation point on the other end side.

[0033] When noise invades a specific position of the transmission cable 40, the noise propagates in the transmission cable 40, and the sensor 11a and the sensor 11b simultaneously observe the noise waveform as a time-versus-voltage at observation points at both ends of the transmission cable 40.

[0034] The storage unit 12 is constituted by a memory, and stores noise waveforms simultaneously measured by the sensor 11 a and the sensor 11 b at respective ends of the transmission cable 40 as observation points as simultaneously measured time-varying noise waveforms.

[0035] The analysis setting / model input unit 20 sets a transmission line model 40S based on the electrical characteristics of the transmission cable 40 and outputs the model to the calculation unit 30 .

[0036] The analysis setting / model input unit 20 outputs the minute time Δt to the calculation unit 30. The cell size and minute time Δt of the transmission line model 40S are about 1 / 10 of the wavelength of the main frequency component of the noise waveform to be measured.

[0037] In the first embodiment, the analysis setting / model input unit 20 sets the transmission line model 40S and the minute time Δt in advance by reflecting the electrical characteristics of the transmission cable 40, but it can also be configured to generate the transmission line model 40S and the minute time Δt based on the noise waveform propagated from the transmission cable 40 and detected by the sensors 11a, 11b.

[0038] The operation unit 30 receives a pair of noise waveforms measured simultaneously from the measuring unit 10, time-reverses the received pair of noise waveforms, uses two observation points of the measuring unit 10 as signal sources of the time-reversed noise in the transmission line model 40S from the analysis setting / model input unit 20, implements a transmission path analysis that traces back time based on the time-reversed noise waveforms, and outputs the position of the peak value obtained based on the transmission path analysis result as the intrusion position of the noise.

[0039] The calculation unit 30 includes a time-reversed signal calculation unit 31 , a voltage distribution calculation unit 32 , a peak detection unit 33 , and an output unit 34 , and is composed of a CPU or a microprocessor.

[0040] The time-reversed signal calculation unit 31 receives Figure 3 The pair of noise waveforms N1 and N2 measured at the same time and stored in the storage unit 12 of the measuring unit 10 shown in (a) are respectively time-reversed to transform the pair of noise waveforms N1 and N2 into Figure 3 The time-reversed signals RN1 and RN2 shown in (b) are obtained by rearranging the data representing the noise waveforms N1 and N2 in reverse time order.

[0041] The voltage distribution calculation unit 32 receives the transmission line model 40S from the analysis setting / model input unit 20 and the time-reversed signals RN1 and RN2 from the time-reversed signal calculation unit 31. Figure 4 As shown in (b), in the transmission line model 40S, the observation points of the measuring unit 10, i.e., the two ends of the transmission cable 40, are set as the positions of the signal sources of the time-reversed signals RN1 and RN2, and a transmission path analysis is performed by tracing back the time using the time-reversed signals RN1 and RN2 as excitation waveforms. The transmission path analysis at this time is a signal transmission simulation in the time domain using the FDTD method (Finite Difference Time Domain method).

[0042] That is, the voltage distribution calculation unit 32 calculates the voltage and current distribution at time t from the voltage and current distribution at time t to the voltage and current distribution at time (t-Δt×n) after subtracting the small time Δt set by the analysis setting / model input unit 20. n represents the number of steps from 1 to N, and when n=N, (t-Δt×n)≤0, the voltage distribution calculation unit 32 ends the calculation.

[0043] Alternatively, the calculation end time may be a set rewind time in which time reversal is performed at the number of repetitions set by the peak detection unit 33 minus the micro time Δt when the transmission path analysis result indicates a peak.

[0044] In addition, when the loss of the transmission cable 40 is sufficiently small and there is no irreversible structure in the transmission line model 40S, a method of calculating the voltage and current distribution at the time (t+Δt×n) after adding a small time Δt to the time t may be used in the FDTD method, which is a method of calculating the voltage and current distribution at the time (t+Δt×n) after adding a small time Δt to the time t. In this case, since existing software can be used, there is an advantage that the cost can be reduced.

[0045] The peak detection unit 33 receives the transmission path analysis result from the voltage distribution calculation unit 32 after subtracting the micro time Δt each time, and detects the position of the peak obtained from the transmission path analysis result as the position where the noise enters the transmission cable 40 .

[0046] Regarding the transmission path analysis result from the voltage distribution calculation unit 32, the waveform changes of the time-reversed signals RN1 and RN2 are operated in a manner of backtracking in time, so multiple reflections and mode conversion are also reproduced in reverse. That is, by observing the transmission path analysis result while performing time reversal, the inflow position of the noise can be estimated from the position of the peak of the transmission path analysis result. That is, it is possible to Figure 4 (b) shows the estimated position of the noise inflow on the simulator.

[0047] like Figure 4As shown in FIG. 1( a ), the output unit 34 outputs the estimated inflow position of the noise on the simulator determined by the peak detection unit 33 to a monitor (not shown) as the inflow position of the noise into the transmission cable 40 .

[0048] Next, the operation of the noise intrusion position estimation apparatus 100 will be described.

[0049] When high-frequency noise is superimposed on the transmission cable 40 as the measurement object, a pair of sensors 11a and sensor 11b of the measurement unit 10 detect the high-frequency noise via a pair of probes 11a1 and 11b1 connected to two separate observation points of the signal conductor in the transmission cable 40, and simultaneously measure the time change of the noise waveform.

[0050] The temporally changing noise waveform measured simultaneously by the pair of sensors 11a and 11b is stored in the storage unit. The steps up to this point are measurement steps.

[0051] The noise waveform of the time change measured at the same time and stored in the storage unit 12 is read to the calculation unit 30 , and the calculation unit 30 estimates the position where the noise enters the transmission cable 40 .

[0052] pass Figure 5 The flowchart shown explains the operation of the calculation unit 30 to estimate the intrusion position of noise.

[0053] First, in step ST1 , the time-reversed signal calculation unit 31 time-reverses a pair of noise waveforms N1 and N2 input and measured simultaneously, and converts them into time-reversed signals RN1 and RN2 .

[0054] Next, in step ST2, the voltage distribution calculation unit 32 sets both ends of the transmission cable 40 as the positions of the signal sources of the time-reversed signals RN1 and RN2 in the transmission line model 40S from the analysis setting / model input unit 20. The voltage distribution calculation unit 32 performs a transmission path analysis of the FDTD method that uses the time-reversed signals RN1 and RN2 from the time-reversed signal calculation unit 31 as excitation waveforms to trace back in time. First, the voltage distribution calculation unit 32 calculates the voltage and current distribution of the time-reversed signals RN1 and RN2 at time t, and provides the calculation results to the peak detection unit 33.

[0055] In step ST3 , the voltage and current distributions of the time-reversed signals RN1 and RN2 at time t-Δt (n=1) are calculated, and the calculation results are provided to the peak detection unit 33 .

[0056] At step ST4 , the peak detection unit 33 determines the peak value based on the voltage and current distribution of the time-reversed signals RN1 and RN2 from the voltage distribution calculation unit 32 , and the process proceeds to step ST5 .

[0057] In step ST5 , it is determined whether the transmission path analysis result satisfies the termination condition, that is, whether (t-Δt×n)≤0, whether the number of repetitions of the calculation by the voltage distribution calculation unit 32 is satisfied, and whether the wraparound time is satisfied.

[0058] When the termination condition is not met, multiply Δt by the value of n plus 1, return to step ST3, calculate the voltage and current distribution of the time reversal signals RN1 and RN2 at the time t-Δt×2 (n=2), enter step ST4, step ST5, and repeat step ST5→step ST3→step ST4→step ST5 until the transmission path analysis result passes step ST5 and meets the termination condition.

[0059] That is, the voltage distribution calculation unit 32 calculates the voltage and current distributions of the time-reversed signals RN1 and RN2 by going back to the past from the time t to when the end condition is satisfied.

[0060] In step ST5 , when the transmission path analysis result satisfies the end condition, the process proceeds to step ST6 , and the output unit 34 outputs the peak position obtained by the peak detection unit 33 based on the transmission path analysis result as the inflow position of noise into the transmission cable 40 to the monitor.

[0061] As a result, the monitor displays the position where the high-frequency noise has invaded the transmission cable 40. Steps ST1 to ST5 are calculation steps.

[0062] As described above, the noise intrusion position estimation device according to the first embodiment can determine the intrusion position of the noise intruding into the transmission cable based on the measurement results from the two observation points of the transmission cable.

[0063] The noise intrusion position estimation device 100 of the first embodiment includes a Figure 1 The entire device of the measuring unit 10, analysis setting / model input unit 20 and calculation unit 30 of the constituent elements shown also includes a system in which the measuring unit 10, analysis setting / model input unit 20 and calculation unit 30 are divided into devices and these multiple devices are set as an aggregate.

[0064] When the system is divided into the measuring unit 10 , the analysis setting / model input unit 20 , and the computing unit 30 , existing devices can be used as the respective devices, thereby having an advantage of being able to reduce costs.

[0065] Implementation Method 2

[0066] use Figure 6 to Figure 8 The noise intrusion position estimation device 100 according to the second embodiment will be described.

[0067] The noise intrusion position estimation device 100 of the second embodiment targets the transmission cable 40 having a differential pair of signal conductors. Compared with the noise intrusion position estimation device 100 of the first embodiment, the measurement unit 10 has a pair of detection units 11a, 11c and 11b, 11d for the differential pair of signal conductors 40a, 40b, respectively, and a mode voltage calculation unit 35 is added to the calculation unit 30. Other aspects are the same as those of the noise intrusion position estimation device 100 of the first embodiment.

[0068] In addition, the same reference numerals in the drawings represent the same or corresponding parts.

[0069] The measurement unit 10 includes a pair of sensors 11a and 11b corresponding to one signal conductor 40a of a differential pair of signal conductors in the transmission cable 40 , a pair of sensors 11c and 11d corresponding to the other signal conductor 40b of the differential pair of signal conductors, and a storage unit 12 .

[0070] That is, the first sensor 11a and the third sensor 11c constitute one sensor, and operate in the same manner as the first sensor in Embodiment 1, and the one sensor constitutes a paired sensor. The second sensor 11b and the fourth sensor 11d constitute another sensor, and operate in the same manner as the second sensor in Embodiment 1, and the other sensor constitutes a paired sensor. A pair of sensors 11a and 11c and another pair of sensors 11b and 11d constitute a pair of sensors.

[0071] The sensors 11 a to 11 d are detection units that simultaneously measure temporal changes in noise waveforms.

[0072] like Figure 7 As shown, the probe 11a1 of the sensor 11a is connected to one end of a signal conductor 40a of the transmission cable 40, that is, to an observation point on one end side of the two observation points. Figure 7 As shown, the probe 11 b 1 of the sensor 11 b is connected to the other end of one signal conductor 40 a of the transmission cable 40 , that is, to the observation point on the other end side of the two observation points.

[0073] like Figure 7 As shown, the probe 11c1 of the sensor 11c is connected to one end of the other signal conductor 40b of the transmission cable 40, that is, to an observation point on one end side. Figure 7 As shown, the probe 11d1 of the sensor 11d is connected to the other end of the other signal conductor 40b of the transmission cable 40, that is, to an observation point on the other end side.

[0074] When noise invades a specific position of the transmission cable 40, the noise propagates in the signal conductors 40a, 40b of the differential pair of the transmission cable 40, and at the observation points at both ends of the signal conductors 40a, 40b, sensors 11a~sensor 11d simultaneously observe the noise waveform as a time-relative voltage.

[0075] Furthermore, although one pair of signal conductors is shown as the signal conductors of the differential pair, when there are two or more differential pairs, the same structure may be adopted for the signal conductors of each differential pair.

[0076] The operation unit 30 receives a pair of noise waveforms measured simultaneously from the measurement unit 10, time-reverses the received pair of noise waveforms, uses two observation points as the positions of the signal source of the time-reversed noise in the transmission line model (40S) from the analysis setting / model input unit 20 reflecting the electrical characteristics of the transmission cable (40), implements a transmission path analysis using the time-reversed waveform as the excitation waveform, and outputs the position of the peak value of the model voltage value obtained based on the transmission path analysis result as the intrusion position of the noise into the transmission cable (40).

[0077] The operation of the analog voltage value in the operation unit 30 is to set the time-reversed waveform to a differential mode waveform for respectively becoming a voltage difference in one sensor 11a, 11c and the other sensor 11b, 11d of the paired sensor, and a common mode waveform for respectively becoming 1 / 2 of the voltage sum in one sensor 11a, 11c and the other sensor 11b, 11d of the paired sensor.

[0078] The intrusion position of the noise output by the operation unit 30 is set to a mode conversion position and a common noise intrusion position. The mode conversion position is the position of the peak value in the differential mode voltage value obtained by the differential mode waveform, and the common noise intrusion position is the position of the peak value in the common mode voltage value obtained by the common mode waveform.

[0079] Mode voltage refers to differential mode voltage and common mode voltage.

[0080] When the voltages of the signal conductors of the differential pair at a position x on the transmission cable 40 are respectively represented by v1(x) and v2(x), the differential mode voltage vdiff(x) at the position x on the transmission cable 40 is expressed by the following equation (1).

[0081] vdiff(x)=v1(x)-v2(x) (1)

[0082] In addition, the common mode voltage vcomm(x) is expressed by the following equation (2).

[0083] vcomm(x)=(v1(x)+v2(x)) / 2 (2)

[0084] The calculation unit 30 includes a time-reversed signal calculation unit 31 , a voltage distribution calculation unit 32 , a mode voltage calculation unit 35 , a peak detection unit 33 , and an output unit 34 , and is composed of a CPU or a microprocessor.

[0085] The time-reversal signal calculation unit 31 and the voltage distribution calculation unit 32 have the same functions as those in the first embodiment.

[0086] The analog voltage calculation unit 35 has two functions: a function of obtaining the analog conversion position and a function of obtaining the common noise intrusion position. Alternatively, the analog voltage calculation unit 35 may have either the function of obtaining the analog conversion position or the function of obtaining the common noise intrusion position.

[0087] In the function of obtaining the mode conversion position, the mode voltage calculation unit 35 calculates the differential mode voltage vdiff(x) according to the voltage and current distribution at time t from the voltage distribution calculation unit 32 and the voltage and current distribution at time (t-Δt×n) after subtracting the small time Δt set by the analysis setting / model input unit 20, and obtains the waveform of the differential mode set as the voltage difference in one sensor (11a, 11c) and the other sensor (11b, 11d) of the paired sensors, respectively.

[0088] When the voltage distribution calculation unit 32 completes the calculation of the voltage and current distribution, the analog voltage calculation unit 35 outputs the peak position of the voltage value of the differential mode voltage vdiff(x) calculated for each micro time Δt before the calculation of the voltage distribution calculation unit 32 is completed as the analog conversion position.

[0089] On the other hand, in the function of obtaining the common noise intrusion position, the common-mode voltage calculation unit 35 calculates the common-mode voltage vcomm(x) according to the voltage and current distribution at time t from the voltage distribution calculation unit 32, and the voltage and current distribution at time (t-Δt×n) after subtracting the small time Δt set by the analysis setting / model input unit 20, and in one sensor (11a, 11c) and the other sensor (11b, 11d) of the paired sensors, the waveforms of the common modes of the voltages and are respectively used, and the common-mode voltage vcomm(x) is calculated according to the above formula (2).

[0090] When the voltage distribution calculation unit 32 completes the calculation of the voltage and current distribution, the common mode voltage calculation unit 35 outputs the peak position of the common mode voltage vcomm(x) calculated for each micro time Δt before the calculation of the voltage distribution calculation unit 32 is completed as the common mode noise intrusion position.

[0091] The output unit 34 outputs the mode conversion position of the noise on the simulator and the common noise intrusion position determined by the mode voltage calculation unit 35 to a monitor (not shown) as the mode conversion position and the noise intrusion position of the noise in the transmission cable 40 .

[0092] Generally speaking, when noise enters the transmission cable 40 having a differential pair of signal conductors, it first enters as a common mode voltage, and is converted into a mode by an unbalanced portion of the transmission cable 40 to generate a differential mode voltage.

[0093] Therefore, the position of the peak in the voltage value of the common mode voltage vcomm(x) obtained by the function of obtaining the common noise intrusion position of the common mode voltage calculation unit 35 specifies the intrusion position of the noise into the transmission cable 40 .

[0094] The peak position of the voltage value of the differential mode voltage vdiff(x) obtained by the function of obtaining the mode conversion position of the mode voltage calculation unit 35 identifies the mode conversion position (unbalanced portion) of the noise to the transmission cable 40 .

[0095] Next, the operation of the noise intrusion position estimation apparatus 100 will be described.

[0096] When high-frequency noise is superimposed on the transmission cable 40 as a measurement object, one sensor 11a, 11c and the other sensor 11b, 11d of a pair of paired sensors of the measuring unit 10 detect the high-frequency noise via one probe 11a1, 11c1 and the other probe 11b1, 11d1 of a pair of paired probes connected to two separate observation points of a pair of signal conductors in the transmission cable 40, and simultaneously measure the time change of the noise waveform.

[0097] The temporally varying noise waveforms simultaneously measured by one sensor 11a, 11c and the other sensor 11b, 11d of the sensor pair are stored in the storage unit. The steps up to this point are measurement steps.

[0098] The noise waveform of the time change measured at the same time and stored in the storage unit 12 is read to the calculation unit 30 , and the calculation unit 30 estimates the position where the noise enters the transmission cable 40 .

[0099] pass Figure 8 The flowchart shown explains the operation of the calculation unit 30 to estimate the intrusion position of noise.

[0100] First, in step ST11 , the time-reversed signal calculation unit 21 time-reverses a pair of noise waveforms N1 , N3 and N2 , N4 input and measured simultaneously, and converts them into time-reversed signals RN1 , RN3 and RN2 , RN4 .

[0101] Next, in step ST12, the voltage distribution calculation unit 32 sets the two ends of the transmission cable 40 as the positions of the signal sources of the time-reversed signals RN1, RN3, RN2, and RN4 in the transmission line model 40S from the analysis setting / model input unit 20. The voltage distribution calculation unit 32 performs a transmission path analysis of the FDTD method that uses the time-reversed signals RN1, RN3, RN2, and RN4 from the time-reversed signal calculation unit 31 as excitation waveforms to trace back in time. First, the voltage distribution calculation unit 32 calculates the voltage and current distribution of the time-reversed signals RN1, RN3, RN2, and RN4 at time t, and provides the calculation results to the model voltage calculation unit 35.

[0102] In step ST13 , the differential mode voltage calculation unit 35 calculates the differential mode voltage vdiff(x) based on the above equation (1).

[0103] In step ST14 , the common mode voltage calculation unit 35 calculates the common mode voltage vcomm(x) based on the above equation (2).

[0104] Next, in step ST15 , the voltage and current distribution of the time-reversed signals RN1 , RN3 , RN2 , and RN4 at time t-Δt (n=1) from the time-reversed signal calculation unit 31 is calculated, and the calculation result is provided to the analog voltage calculation unit 35 .

[0105] The differential mode voltage calculation unit 35 calculates the differential mode voltage vdiff(x) in step ST16 , calculates the common mode voltage vcomm(x) in step ST17 , and proceeds to step ST18 .

[0106] In step ST18 , it is determined whether the transmission path analysis result satisfies the termination condition, that is, whether (t-Δt×n)≤0, whether the number of repetitions of the calculation by the voltage distribution calculation unit 32 is satisfied, and whether the wraparound time is satisfied.

[0107] When the termination condition is not met, multiply Δt by the value of n plus 1, return to step ST15, calculate the voltage and current distribution of the time-reversed signals RN1, RN3, RN2, and RN4 at time t-Δt×2 (n=2), enter steps ST16, ST17, and ST18, and repeat step ST18→step ST15→step ST16→step ST17→step ST18 until the transmission path analysis result passes step ST18 and meets the termination condition.

[0108] That is, the voltage distribution calculation unit 32 calculates the voltage and current distributions of the time-reversed signals RN1 , RN3 , RN2 , and RN4 by going back to the past from the time t to when the end condition is satisfied.

[0109] In step ST18, when the transmission path analysis result meets the end condition, step ST19 is entered, and the position of the peak value in the voltage value of the differential mode voltage vdiff(x) obtained by the mode voltage calculation unit 35 is output to the monitor as the mode conversion position, and the position of the peak value in the voltage value of the common mode voltage vcomm(x) obtained by the mode voltage calculation unit 35 is output to the monitor as the common noise intrusion position.

[0110] As a result, the common noise intrusion position and mode conversion position (unbalanced portion) of the high-frequency noise in the transmission cable 40 are displayed on the monitor, and the intrusion position of the high-frequency noise into the transmission cable 40 can be determined with high accuracy, and the mode conversion position (unbalanced portion) can be determined, so that more appropriate noise countermeasures can be implemented.

[0111] Steps ST11 to ST18 are calculation steps.

[0112] In the second embodiment, the voltage distribution calculation unit 32 has both functions of obtaining the mode conversion position and the common noise intrusion position. However, the voltage distribution calculation unit 32 may have either one of the two functions depending on the application.

[0113] Furthermore, the various embodiments may be freely combined, or arbitrary components of the various embodiments may be modified or omitted.

[0114] Industrial Applicability

[0115] The noise intrusion position estimation device of the present invention is suitable for an apparatus for estimating the intrusion position of high-frequency noise into a transmission cable having a balanced transmission path having a pair of signal conductors for propagating high-frequency signals.

[0116] Explanation of symbols

[0117] 100: noise intrusion position estimation device; 10: measuring unit; 11a: first sensor; 11b: second sensor; 11c: third sensor; 11d: fourth sensor; 11a1 to 11d1: probes; 12: memory; 20: analysis setting / model input unit; 30: operation unit; 31: time reversal signal operation unit; 32: voltage distribution operation unit; 33: peak detection unit; 34: output unit; 35: analog voltage operation unit; 40: transmission cable.

Claims

1. A noise intrusion position estimation device, the noise intrusion position estimation device comprising: a measuring unit having a pair of paired detection units that simultaneously measure temporal changes in noise waveforms on a transmission cable at two separate observation points of the transmission cable having paired signal conductors; and a calculation unit that receives a pair of noise waveforms measured simultaneously from the measurement unit, time-reverses the received pair of noise waveforms, uses the two observation points as positions of signal sources of the time-reversed noise in a transmission line model that reflects the electrical characteristics of the transmission cable, performs a transmission path analysis using the time-reversed waveforms as excitation waveforms, and outputs the position of a peak value in a modulated voltage value obtained based on the result of the transmission path analysis as a position where the noise invades the transmission cable, The operation of the mode voltage value in the operation unit is to use the time-reversed waveform as a common mode waveform in one detection unit and the other detection unit of the paired detection units, respectively, and the common mode waveform is used to obtain 1 / 2 of the voltage sum as the common mode voltage value. The intrusion position of the noise outputted from the calculation unit is set as a common noise intrusion position, which is a peak position of a common mode voltage value obtained as a result of a transmission path analysis performed on the common mode waveform.

2. A noise intrusion position estimation device, the noise intrusion position estimation device comprising: a measuring unit having a pair of detection units that simultaneously measure a temporal change in a noise waveform on a transmission cable at two separate observation points of a transmission cable having a differential pair of signal conductors; and a calculation unit that receives a pair of noise waveforms measured simultaneously from the measurement unit, time-reverses the received pair of noise waveforms, uses the two observation points as positions of signal sources of the time-reversed noise in a transmission line model that reflects the electrical characteristics of the transmission cable, performs a transmission path analysis using the time-reversed waveforms as excitation waveforms, and outputs the position of a peak value in a modulated voltage value obtained based on the result of the transmission path analysis as a position where the noise invades the transmission cable, The operation of the mode voltage value in the operation unit is to use the time-reversed waveform in one detection unit and the other detection unit of the paired detection unit as a differential mode waveform, and the differential mode waveform is used to obtain the voltage difference as the differential mode voltage value, and to use the time-reversed waveform in one detection unit and the other detection unit of the paired detection unit as a common mode waveform, and the common mode waveform is used to obtain 1 / 2 of the voltage sum as the common mode voltage value. The intrusion position of the noise output by the operation unit is set as a mode conversion position and a common noise intrusion position, wherein the mode conversion position is the position of the peak value of the differential mode voltage value obtained by the differential mode waveform, and the common noise intrusion position is the position of the peak value of the common mode voltage value obtained by the common mode waveform.

3. A noise intrusion position estimation method, the noise intrusion position estimation method having: a measuring step of simultaneously measuring a time change of a noise waveform on a transmission cable at two separate observation points of the transmission cable having a differential pair of signal conductors; and A calculation step of time-reversing a pair of noise waveforms simultaneously measured by the measurement step, using the two observation points as positions of signal sources of the time-reversed noise in a transmission line model reflecting the electrical characteristics of the transmission cable, using the time-reversed waveform as a differential mode waveform, the differential mode waveform being used to obtain a voltage difference as a differential mode voltage value, using the time-reversed waveform as a common mode waveform, the common mode waveform being used to obtain 1 / 2 of a voltage sum as a common mode voltage value, using the position of a peak value in the differential mode voltage value obtained by the differential mode waveform as a mode conversion position of the transmission cable, and using the position of a peak value in the common mode voltage value obtained by the common mode waveform as a common noise intrusion position into the transmission cable.

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