JP7291089B2 - Cable deterioration determination method and cable deterioration determination device - Google Patents

Description

The present disclosure relates to a cable deterioration determination method and a cable deterioration determination device.

Known methods for determining the presence or absence of cable disconnection and the position of the disconnection include TDR (time domain reflectance) measurement using an oscilloscope and FDR (frequency domain reflectance) measurement using a network analyzer. . For example, Patent Literatures 1 and 2 disclose that a network analyzer is used to perform a cable characteristic test by frequency domain reflectometry.

JP 2014-10027 A JP 2015-72217 A

It is conceivable to use frequency domain reflectometry to detect the presence and location of reflectors (ie, degraded areas) in the cable. In the frequency domain reflectometry method, a frequency band (range of frequency sweep) is set as a measurement range for acquiring frequency response characteristics. Patent Documents 1 and 2 suggest that the signal level is improved by widening the frequency band. It is conceivable to detect the presence or absence of deterioration of the cable using methods such as those disclosed in Patent Documents 1 and 2, but it is considered that the degree of deterioration cannot be grasped.

As a result of intensive studies by the inventors of the present application, it has been found that, in the frequency response characteristics of the cable, the frequency spectrum of the deteriorated portion that serves as a reflection source varies greatly depending on the form of deterioration.

Therefore, the reflection level (the amplitude ratio of the reflected wave to the input wave) at the deteriorated portion varies depending on the relationship between the frequency band set at the time of measurement and the frequency spectrum of the reflection source. For example, when the set frequency band is far from the frequency spectrum of the reflection source, the reflection level of the reflection source is reduced, and the S/N (Signal to Noise ratio) is lowered. On the other hand, if the frequency band is set to be sufficiently broader than the frequency spectrum of the reflection source, the frequency resolution becomes rough and the integrated value becomes small when converting to the time domain, so the S/N similarly decreases. Therefore, it is difficult to quantitatively evaluate the reflectance of the reflection source (that is, deteriorated portion) included in the cable.

In view of the above circumstances, the present disclosure provides a cable deterioration determination method and a cable deterioration determination device that can be quantified by improving the S/N in detecting the reflection level of the reflection source included in the cable. With the goal.

The cable deterioration determination method according to the present disclosure includes:
obtaining a first frequency response characteristic in a first frequency band of the cable by frequency domain reflectometry;
selecting a second frequency band of the first frequency band that contains the frequency spectrum of a reflector contained in the cable based on the difference between the first frequency response and a known reference frequency response of the cable; and,
obtaining a second frequency response characteristic of the cable in the second frequency band;
including.

The cable deterioration determination device according to the present disclosure includes:
a test executive configured to obtain a frequency response characteristic of the cable by frequency domain reflectometry;
a storage unit for storing known reference frequency response characteristics of the cable;
Based on the difference between the first frequency response characteristic in the first frequency band of the cable and the reference frequency response characteristic obtained by the test execution unit, the reflector included in the cable in the first frequency band a selection unit that selects a second frequency band including the frequency spectrum of
a setting unit that sets the second frequency band in the test execution unit as a frequency band for acquiring a second frequency response characteristic of the cable;
Prepare.

According to the present disclosure, it is possible to improve the S/N and quantify the degree of deterioration in detecting the reflection level of the reflection source included in the cable.

It is a figure which shows roughly an example of the connection state of the deterioration determination apparatus of the cable which concerns on one Embodiment, and a cable. 1 is a block diagram showing the configuration of a cable deterioration determination device according to an embodiment; FIG. 5 is a graph for explaining an example of a difference between a first frequency response characteristic and a reference frequency response characteristic; FIG. 4 is a conceptual diagram for explaining a method of selecting a second frequency band; 7 is a graph showing an example of a relationship between a cable characteristic impedance difference before correction based on a correction coefficient and a cable position; 7 is a graph showing an example of the relationship between the change in the characteristic impedance of the cable after correction based on the correction coefficient and the cable position; 7 is a graph for explaining an example of a difference between a first frequency response characteristic and a reference frequency response characteristic when a plurality of frequency spectrums are included; FIG. 4 is a conceptual diagram for explaining a method of selecting a second frequency band when a plurality of frequency spectrums are included; 4 is a flow chart showing a procedure of a cable deterioration determination method according to one embodiment.

Several embodiments will now be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the invention, but are merely illustrative examples. .
For example, expressions denoting relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" are strictly not only represents such an arrangement, but also represents a state of relative displacement with a tolerance or an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous", which express that things are in the same state, not only express the state of being strictly equal, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, expressions that express shapes such as squares and cylinders do not only represent shapes such as squares and cylinders in a geometrically strict sense. The shape including the part etc. shall also be represented.
On the other hand, the expressions "comprising", "comprising", "having", "including", or "having" one component are not exclusive expressions excluding the presence of other components.

(Cable deterioration determination device)
A cable deterioration determination apparatus 100 according to an embodiment will be described below. FIG. 1 is a diagram schematically showing an example of a connection state between a cable deterioration determination device 100 and a cable 200 according to one embodiment.

As shown in FIG. 1 , the cable deterioration determination device 100 is connected to one end 201 of a cable 200 . The cable deterioration determination apparatus 100 is configured to input incident signals of voltages or electromagnetic waves of various frequencies from one end 201 to the other end 202 of a cable 200 and acquire frequency response characteristics. For example, if the cable 200 has a deteriorated portion or a disconnection portion, the incident signal input to the cable deterioration determination device 100 is reflected at that portion. When the cable 200 has no deteriorated portion or disconnected portion, no reflected wave of the incident signal is observed when the other end 202 of the cable 200 is provided with a terminator, and the other end 202 of the cable 200 is not provided with a terminator. , a reflected wave of the incident signal from the other end 202 of the cable 200 is observed.

Note that the cable 200 is wound in the example shown in FIG. However, the actual deterioration determination target may be the existing cable 200, or the cable 200 may be in a state in which it is not wound.

In the example shown in FIG. 1 , the cable deterioration determining apparatus 100 is configured to generate an incident signal and measure the frequency response characteristics of the cable 200 . However, the cable deterioration determination device 100 is not limited to such a configuration. For example, the cable deterioration determination apparatus 100 may be configured to be used in combination with a network analyzer, input measurement conditions to the network analyzer, and acquire frequency response characteristics measured by the network analyzer. That is, the cable deterioration determination apparatus 100 may be configured to acquire the frequency response characteristic from another apparatus.

FIG. 2 is a block diagram showing the configuration of the cable deterioration determination device 100 according to one embodiment. As shown in FIG. 2, the cable deterioration determination apparatus 100 includes a storage unit 11 that stores various data, an input unit 12 that receives user input, a measurement unit 13 that measures frequency response characteristics, and an acquired frequency response. A display unit 14 for displaying characteristics and a control unit 15 for controlling the entire device are provided. These components are interconnected by bus lines 16 . Note that these components may be connected by communication such as Ethernet (registered trademark) or USB.

As described above, in the cable deterioration determination device 100, the measurement unit 13 that measures the frequency response characteristic may be an independent device (for example, a network analyzer). In this case, the cable deterioration determination apparatus 100 may be configured to include a communication unit (not shown), output measurement conditions to a network analyzer, and acquire measurement results from the network analyzer via the communication unit. Further, the cable deterioration determination device 100 may be configured without the display unit 14 .

The storage unit 11 includes a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The storage unit 11 stores programs for executing various control processes, various data, and the like. For example, the storage unit 11 stores known reference frequency response characteristics of the cable 200 . Note that the storage unit 11 may store data on reference frequency response characteristics and data on acquired frequency response characteristics. The reference frequency response characteristic is the frequency response characteristic when the cable 200 has no deterioration. For example, the reference frequency response characteristic is data obtained by measuring during or before installation of the cable 200 and used in subsequent deterioration determination.

The input unit 12 is composed of input devices such as operation buttons, a keyboard, a pointing device, and a microphone. The input unit 12 is an input interface used by the user to input instructions.

The measurement unit 13 is configured to output an incident signal to the cable 200 and measure the frequency response characteristic indicating the reflected signal.

The display unit 14 is configured by a display device such as an LCD (Liquid Crystal Display) or an EL (Electroluminescence) display. The display unit 14 displays text, images, waveforms, and the like.

The control unit 15 is composed of a processor such as a CPU (Central Processing Unit). The control unit 15 controls the operation of the entire device by executing programs stored in the storage unit 11 .

The functional configuration of the control unit 15 will be described below. The control unit 15 functions as a test execution unit 151 , a selection unit 152 , a setting unit 153 , a correction coefficient acquisition unit 154 , a parameter calculation unit 155 and a parameter correction unit 156 .

The test executor 151 is configured to obtain the frequency response characteristics of the cable 200 by frequency domain reflectometry. The test execution unit 151 acquires the frequency response characteristics by controlling the measurement unit 13 and measuring the frequency response characteristics. Note that the test execution unit 151 may control another device to acquire the frequency response characteristic. The frequency response characteristics acquired by test executing section 151 include a first frequency response characteristic and a second frequency response characteristic.

Based on the difference between the first frequency response characteristic in the first frequency band of the cable 200 and the reference frequency response characteristic, the selection unit 152 selects a first frequency spectrum including the frequency spectrum of the reflection source included in the cable 200 in the first frequency band. Select two frequency bands. The reference frequency response characteristic is a known frequency response characteristic, for example, the frequency response characteristic of the cable 200 previously acquired by frequency domain reflectometry. The selection unit 152 may select the second frequency band based on the integrated value of the absolute value of the difference between the first frequency response characteristic and the reference frequency response characteristic.

Here, a method for selecting the second frequency band by the selection unit 152 will be described in detail with reference to FIGS. 3 and 4. FIG. FIG. 3 is a graph for explaining an example of the difference between the first frequency response characteristic and the reference frequency response characteristic. In FIG. 3, the first frequency response characteristic is the waveform indicated by the solid line, the reference frequency response characteristic is the waveform indicated by the dashed line, and the difference between them is the waveform indicated by the thick line. In this example, the first frequency band is 0 to f ₁ (MHz) and the second frequency band is 0 to f ₂ (MHz). The second frequency band is narrower than the first frequency band. Since the frequency response characteristic is the reflection level, it cannot be negative. However, the difference in frequency response characteristics has positive and negative values. The first frequency band may be set to the maximum measurement range of the measuring section 13 .

FIG. 4 is a conceptual diagram for explaining a method of selecting the second frequency band. To select the second frequency band, first, the integrated value of the absolute value of the difference between the first frequency response characteristic and the reference frequency response characteristic is calculated. If the absolute value of the waveform of the difference shown in FIG. 3 is frequency-integrated, it can be seen that the integrated value gradually increases. Among them, a frequency region in which the increment of the integrated value is larger than the reference value is selected as the second frequency band. For example, as shown in FIG. 4, when the integrated value increases significantly in the low frequency range but does not increase significantly in the high frequency range, the section of the low frequency range is selected as the second frequency band.

The setting unit 153 sets the second frequency band selected by the selection unit 152 to the test execution unit 151 as the frequency band for acquiring the second frequency response characteristic of the cable 200 . Note that the setting unit 153 sets the first frequency band to the test execution unit 151 when acquiring the first frequency response characteristic.

The correction coefficient acquisition unit 154 acquires a correction coefficient by dividing an integrated value obtained by integrating the reflection level of the second frequency response characteristic over a predetermined frequency band by the predetermined frequency band. That is, the correction coefficient is a coefficient corresponding to the average reflection level. Reflection level is the amplitude ratio of the reflected wave to the incident wave. The predetermined frequency band is preferably the second frequency band.

The parameter calculator 155 calculates a parameter representing the characteristic impedance of the cable 200 in the section including the reflection source from the second frequency response characteristic. The parameter representing the characteristic impedance is, for example, the characteristic impedance of the section including the reflection source calculated from the second frequency response characteristic. The parameter representing the characteristic impedance may be the difference between the characteristic impedance and the characteristic impedance of the section including the reflection source calculated from the reference frequency response characteristic.

A parameter correction unit 156 corrects the parameter representing the characteristic impedance based on the correction coefficient. For example, here, the significance of the correction by the correction coefficient will be described with reference to FIGS. 5 and 6. FIG.

FIG. 5 is a graph showing an example of the relationship between the characteristic impedance difference of the cable 200 before correction based on the correction coefficient and the cable position. This example shows the characteristic impedance difference obtained when the cable 200 is subjected to simulated deterioration having the same degree of deterioration at three different cable positions. The characteristic impedance difference means the difference between the characteristic impedance of cable 200 subjected to simulated deterioration and the characteristic impedance of cable 200 not subjected to simulated deterioration. A position where the characteristic impedance difference is large corresponds to a position where simulated deterioration is provided.

As shown in FIG. 5, as a result of simulated deterioration at three cable positions, the difference in characteristic impedance due to simulated deterioration is greatly different. Although the actual simulated deterioration has the same degree of deterioration, the same characteristic impedance difference is not obtained. Therefore, without correction based on the correction coefficient, it is not possible to quantitatively obtain the parameter representing the characteristic impedance. As a result, it is not possible to quantitatively determine the degree of deterioration based on parameters representing characteristic impedance.

FIG. 6 is a graph showing an example of the relationship between the change in the characteristic impedance of the cable 200 after correction based on the correction coefficient and the cable position. As shown in FIG. 6, when correction is performed based on the correction coefficient, the change in characteristic impedance due to simulated deterioration is substantially constant regardless of the position of simulated deterioration. Therefore, it is possible to quantitatively obtain a parameter representing the characteristic impedance. As a result, it is also possible to quantitatively determine the degree of deterioration based on the parameter representing the characteristic impedance.

Thus, it was confirmed in the simulated deterioration experiment that the degree of deterioration can be quantified by correction using the correction coefficient. According to the knowledge of the inventors of the present application, for example, the further the position of the deteriorated portion is from the input side (one end 201 of the cable 200), the smaller the change in the characteristic impedance. The farther from one end 201), the narrower the effective frequency spectrum width, and the larger the correction coefficient tends to be. Therefore, it can be quantified by multiplying a parameter representing characteristic impedance (for example, peak value of change in characteristic impedance) by a correction factor.

Basically, one reflection source corresponds to one frequency spectrum. If there are multiple reflectors, their frequency spectra may overlap or be different from each other. If there are multiple reflectors, there may be multiple frequency spectra. In such a case, the following processing can be considered.

FIG. 7 is a graph for explaining an example of the difference between the first frequency response characteristic and the reference frequency response characteristic when multiple frequency spectra are included. It should be noted that the waveform indicated by the dashed line in FIG. 7 indicates the absolute value of the difference. FIG. 8 is a conceptual diagram for explaining a method of selecting the second frequency band when a plurality of frequency spectrums are included.

As shown in FIG. 7, when the difference between the first frequency response characteristic and the reference frequency response characteristic includes a plurality of frequency spectra due to reflection, the selector 152 selects the second frequency band for each frequency spectrum. may be selected. For example, in FIGS. 7 and 8, 0 to f ₃ (MHz) is selected as the first second frequency band, and f ₄ to f ₅ (MHz) is selected as the second second frequency band. . In this case, the setting unit 153 sets the test execution unit 151 to acquire the second frequency response characteristics for each of the plurality of second frequency bands. Calculation of parameters representing characteristic impedance, correction based on correction coefficients, and the like are also performed for each of the second frequency response characteristics.

Based on a conversion table showing the relationship between the parameter representing the characteristic impedance of the cable 200 and the degree of degradation of the cable 200, the cable deterioration determining apparatus 100 converts the parameter representing the characteristic impedance of the section including the reflection source into the cable 200. It may be configured to estimate the degree of deterioration. In this case, for example, it is preferable to store a conversion table necessary for estimating the degree of deterioration in the storage unit 11 before performing deterioration determination. The conversion table may be, for example, a correspondence table showing the relationship between the parameter representing the characteristic impedance and the degree of deterioration of the cable 200, or a function for calculating the degree of deterioration of the cable 200 from the parameter representing the characteristic impedance. There may be.

(Method for judging cable deterioration)
A specific example of the cable deterioration determination method will be described below with reference to FIG. FIG. 9 is a flow chart showing the procedure of the cable deterioration determination method according to the embodiment. It should be noted that part or all of each procedure described below may be manually executed by the user. Further, in the cable deterioration determination method described below, each procedure can be appropriately modified so as to correspond to the processing executed by the cable deterioration determination apparatus 100 described above. That is, in the following description, description overlapping with the description of the cable deterioration determination device 100 will be omitted.

As shown in FIG. 9, first, the first frequency response characteristic in the first frequency band of the cable 200 is obtained by frequency domain reflectometry (step S1). Then, based on the difference between the first frequency response and a known reference frequency response of cable 200, a second frequency band of the first frequency band is selected that contains the frequency spectrum of the reflectors contained in cable 200. (Step S2).

A second frequency response characteristic of the cable 200 in the second frequency band is obtained (step S3). A correction coefficient is obtained by dividing the integrated value obtained by integrating the reflection level of the second frequency response characteristic in a predetermined frequency band by the predetermined frequency band (step S4).

Also, a parameter representing the characteristic impedance of the cable 200 in the section including the reflection source is calculated from the second frequency response characteristic (step S5). Next, the parameter representing the calculated characteristic impedance is corrected based on the correction coefficient (step S6).

The present disclosure is not limited to the above-described embodiments, and includes modifications of the above-described embodiments and modes in which these modes are combined as appropriate.

(summary)
The contents described in each of the above embodiments are understood as follows, for example.

(1) A cable deterioration determination method according to an embodiment of the present disclosure includes:
obtaining a first frequency response characteristic in a first frequency band of the cable (200) by frequency domain reflectometry;
A second frequency spectrum comprising a frequency spectrum of a reflector contained in the cable (200) in the first frequency band based on a difference between the first frequency response and a known reference frequency response of the cable (200). selecting a frequency band;
obtaining a second frequency response characteristic of the cable (200) in the second frequency band;
including.

According to the method described in (1) above, in order to obtain the second frequency response characteristic in the second frequency band containing the frequency spectrum of the reflector, S in detecting the reflection level of the reflector included in the cable (200). Quantification becomes possible by improving /N. By using such a second frequency response characteristic, it is possible to more accurately estimate the presence and position of a reflection source (that is, a deteriorated portion) included in the cable (200).

(2) In some embodiments, in the method described in (1) above,
obtaining a correction coefficient by dividing an integrated value obtained by integrating the reflection level of the second frequency response characteristic in a predetermined frequency band by the predetermined frequency band;
calculating a parameter representing the characteristic impedance of the cable (200) in the section containing the reflection source from the second frequency response characteristic;
correcting the parameter representing the characteristic impedance based on the correction coefficient;
including.

The parameter representing the characteristic impedance varies depending on the reflection level of the reflector. Further, according to the findings of the inventors of the present application, the reflection level of the reflection source may vary depending on the position of the reflection source. Therefore, even if the frequency band for obtaining frequency response characteristics is selected by focusing only on the frequency spectrum of the reflection source, it is difficult to quantify the parameter representing the characteristic impedance without considering the influence of the position. be.

As a result of intensive studies by the inventors of the present application, it was found that the effect of position can be suppressed and quantified by obtaining the correction coefficient as described in (2) above and correcting the parameter representing the characteristic impedance using the correction coefficient. found. Therefore, according to the method described in (2) above, since the parameter representing the characteristic impedance is corrected using the correction coefficient, the parameter representing the quantified characteristic impedance can be obtained. In this case, the degree of deterioration of the cable (200) at the position of the reflection source can be quantitatively determined from the parameter representing the characteristic impedance. Also, from the determined degree of deterioration of the cable (200), it is possible to estimate when the cable (200) needs to be repaired or replaced.

(3) In some embodiments, in the method described in (1) or (2) above,
The second frequency band is selected based on the integrated value of the absolute value of the difference between the first frequency response characteristic and the reference frequency response characteristic.

According to the findings of the inventors of the present application, it may be difficult to extract the frequency spectrum of the reflection source buried in noise even by focusing on the difference between the first frequency response characteristic and the reference frequency response characteristic. In this respect, focusing on the integrated value of the absolute value of the difference instead of the difference improves the sensitivity of the frequency spectrum of the reflection source buried in noise. Therefore, according to the method described in (3) above, since such an integral value is used, the second frequency band can be selected with higher accuracy.

(4) In some embodiments, in the method according to any one of (1) to (3) above, a parameter representing the characteristic impedance of the cable (200) and deterioration of the cable (200) It further includes a step of estimating the degree of deterioration of the cable (200) from the parameter representing the characteristic impedance of the section including the reflection source, based on a conversion table showing the relationship between the deterioration degree and the degree of deterioration.

According to the method described in (4) above, the degree of deterioration of the cable (200) can be easily estimated.

(5) In some embodiments, in the method according to any one of (1) to (4) above, the difference between the first frequency response characteristic and the reference frequency response characteristic includes a plurality of the frequencies When the spectrum is included, in the step of selecting the second frequency band, the second frequency band is selected for each frequency spectrum, and the second frequency response characteristic is determined for each of the plurality of second frequency bands. get.

According to the method described in (5) above, when there are a plurality of reflection sources having different frequency spectra in the cable (200), the second frequency band is selected for each of the plurality of frequency spectra, A second frequency response characteristic is obtained. Therefore, it is possible to accurately estimate the presence and positions of a plurality of reflection sources (that is, deteriorated portions) included in the cable (200) from each of the second frequency response characteristics.

(6) A cable deterioration determination device (100) according to an embodiment of the present disclosure,
a test executor (151) configured to obtain frequency response characteristics of the cable by frequency domain reflectometry;
a storage unit (11) for storing known reference frequency response characteristics of the cable (200);
Based on the difference between the first frequency response characteristic in the first frequency band of the cable (200) and the reference frequency response characteristic obtained by the test execution unit (151), the a selection unit (152) that selects a second frequency band that includes the frequency spectrum of the reflector included in the cable (200);
a setting unit (153) for setting the second frequency band in the test execution unit (151) as a frequency band for acquiring the second frequency response characteristic of the cable (200);
Prepare.

According to the configuration described in (6) above, in order for the test execution unit (151) to acquire the second frequency response characteristic in the second frequency band including the frequency spectrum of the reflection source, the reflection source included in the cable (200) Quantification becomes possible by improving the S/N in the detection of the reflection level of . By using such a second frequency response characteristic, it is possible to more accurately estimate the presence and position of a reflection source (that is, a deteriorated portion) included in the cable (200).

11 storage unit 12 input unit 13 measurement unit 14 display unit 15 control unit 16 bus line 100 cable deterioration determination device 151 test execution unit 152 selection unit 153 setting unit 154 correction coefficient acquisition unit 155 parameter calculation unit 156 parameter correction unit 200 cable

Claims (6)

obtaining a first frequency response characteristic in a first frequency band of the cable by frequency domain reflectometry;
selecting a second frequency band of the first frequency band that contains the frequency spectrum of a reflector contained in the cable based on the difference between the first frequency response and a known reference frequency response of the cable; and,
obtaining a second frequency response characteristic of the cable in the second frequency band;
Deterioration determination method for cables including obtaining a correction coefficient by dividing an integrated value obtained by integrating the reflection level of the second frequency response characteristic in a predetermined frequency band by the predetermined frequency band;
calculating a parameter representing the characteristic impedance of the cable in the section containing the reflection source from the second frequency response characteristic;
correcting the parameter representing the characteristic impedance based on the correction coefficient;
The cable deterioration determination method according to claim 1, comprising: 3. The cable deterioration determination method according to claim 1, wherein the second frequency band is selected based on an integrated value of an absolute value of the difference between the first frequency response characteristic and the reference frequency response characteristic. estimating the degree of degradation of the cable from the parameter representing the characteristic impedance of the section including the reflection source based on a conversion table showing the relationship between the parameter representing the characteristic impedance of the cable and the degree of degradation of the cable; 4. The cable deterioration determination method according to claim 1, further comprising a step. When the difference between the first frequency response characteristic and the reference frequency response characteristic includes a plurality of the frequency spectrums, in the step of selecting the second frequency band, the second frequency band for each frequency spectrum and obtaining the second frequency response characteristic for each of the plurality of second frequency bands. a test executive configured to obtain a frequency response characteristic of the cable by frequency domain reflectometry;
a storage unit for storing known reference frequency response characteristics of the cable;
Based on the difference between the first frequency response characteristic in the first frequency band of the cable and the reference frequency response characteristic obtained by the test execution unit, the reflector included in the cable in the first frequency band a selection unit that selects a second frequency band including the frequency spectrum of
a setting unit that sets the second frequency band in the test execution unit as a frequency band for acquiring a second frequency response characteristic of the cable;
Cable deterioration determination device.

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