Multi-core cable measurement method and device, storage medium and product

Abstract

The invention discloses a multi-core cable measurement method and device, a storage medium and a product, and relates to the technical field of cable detection, effective signals are identified from ultrasonic signals transmitted through a detected multi-core cable, and the transmission time of the effective signals in the detected multi-core cable is determined. The effective signal is obtained through signal feature recognition of the source signal corresponding to the ultrasonic signal; acquiring the environment temperature, and compensating and correcting the propagation velocity of the effective signal in the measured multi-core cable according to the core wire material of the measured multi-core cable to obtain the actual propagation velocity; and determining the length of the measured multi-core cable based on the actual propagation speed, the propagation time and the preset path compensation value. By endowing the ultrasonic signal with the signal characteristic, the anti-interference identification in the strong electromagnetic environment is realized, the influence of the environment temperature on the sound velocity is eliminated through temperature compensation correction, the high-precision and full-range non-blind area measurement of the length of the multi-core cable is realized, the measurement precision is obviously improved, and the complexity of the measurement operation is reduced.

Description

Technical Field

[0001] This application relates to the field of cable testing technology, and in particular to a method, apparatus, storage medium and product for measuring multi-core cables. Background Technology

[0002] Accurate measurement of the length of multi-core cables is a fundamental and crucial technical task in power system operation and maintenance, project completion acceptance, and cable production quality inspection. Currently, Time Domain Reflectometry (TDR) is the mainstream technique for measuring the length of power cables. This method involves transmitting an electrical pulse signal into the cable. When the signal encounters a point of impedance discontinuity (such as the cable end, joint, or fault point), it is reflected. By measuring the time difference between the transmitted and reflected pulses and combining this with a preset propagation speed of the signal in the cable, the length of the cable can be calculated.

[0003] However, existing measurement schemes based on pulse-reflection measurement methods are hampered by several limitations when dealing with the precise measurement requirements of multi-core cables. These limitations stem from the variations in signal propagation speeds among power cables from different manufacturers and of different specifications, as well as the significant impact of ambient temperature variations on sound velocity. This results in measurement accuracy being highly dependent on on-site pre-calibration of wave velocity, making the process cumbersome and prone to human error. Furthermore, the lack of identifiable characteristic markers in traditional pulse signals makes them susceptible to strong electromagnetic noise interference in complex substation or underground utility tunnel environments. The receiving end struggles to accurately identify the target reflected signal from the mixed signals, ultimately leading to low measurement accuracy and cumbersome operation for multi-core cable length measurements. Summary of the Invention

[0004] The main purpose of this application is to provide a method, device, storage medium and product for measuring multi-core cables, which aims to solve the technical problems of low measurement accuracy and cumbersome operation of traditional cable length measurement schemes.

[0005] To achieve the above objectives, this application proposes a method for measuring multi-core cables, the method comprising: The effective signal is identified from the ultrasonic signals propagating through the multi-core cable under test, and the propagation time of the effective signal in the multi-core cable under test is determined. The effective signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal. The ambient temperature is obtained, and the propagation speed of the effective signal in the multi-core cable under test is compensated and corrected according to the core material of the multi-core cable under test to obtain the actual propagation speed. The length of the multi-core cable under test is determined based on the actual propagation speed, the propagation time, and the preset path compensation value.

[0006] In one embodiment, the multi-core cable under test includes at least a first core wire and a second core wire; the method further includes: The ultrasonic signal propagating through the multi-core cable under test is obtained by means of a preset measurement conduction loop, wherein the preset measurement conduction loop consists of the first core wire, a signal transmission channel between the first core wire and the second core wire, and the second core wire. The source signal enters the preset measurement conduction loop from the port of the first core wire, and after propagating in the preset measurement conduction loop, it is collected at the port of the second core wire to obtain the ultrasonic signal.

[0007] In one embodiment, the step of identifying a valid signal from the ultrasonic signals propagating through the multi-core cable under test and determining the propagation time of the valid signal in the multi-core cable under test includes: The ultrasonic signal propagating through the multi-core cable under test is decoded to identify signal segments that match the signal characteristics. The signal segment is taken as the effective signal, and the propagation time is determined based on the transmission time of the ultrasonic signal and the reception time of the effective signal.

[0008] In one embodiment, the signal features include bit length features, symbol duration features, and a preset symbol sequence; The step of decoding the ultrasonic signal propagating through the multi-core cable under test and identifying the signal segment that matches the signal characteristics includes: The ultrasonic signal is subjected to amplitude threshold screening, and the signal portion with an amplitude greater than or equal to a preset value is retained to obtain candidate signal segments; Based on the symbol duration feature, the candidate signal segment is time-domain segmented to obtain symbol units; Based on the amplitude characteristics of the symbol unit, the symbol value corresponding to the symbol unit is determined, and the symbol value sequence of the candidate signal segment is obtained; Determine whether the total number of bits in the symbol value sequence of the candidate signal segment is consistent with the bit feature, and whether the symbol value sequence matches the preset symbol sequence; Candidate signal segments that simultaneously satisfy the bit feature and match the preset symbol sequence are identified as signal segments that match the signal feature.

[0009] In one embodiment, the step of acquiring the ambient temperature and compensating for and correcting the propagation speed of the effective signal in the multi-core cable under test according to the core material of the multi-core cable under test to obtain the actual propagation speed includes: Obtain the core material information of the multi-core cable under test; Based on the core wire material information, determine the reference sound velocity and temperature influence coefficient corresponding to the core wire material information; Based on the ambient temperature, the reference sound velocity, and the temperature influence coefficient, the actual propagation speed of the effective signal at the ambient temperature is calculated.

[0010] In one embodiment, the step of determining the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and a preset path compensation value includes: Calculate the total propagation path length of the ultrasonic signal in the multi-core cable under test based on the actual propagation speed and the propagation time; The length of the multi-core cable under test is obtained by subtracting the preset path compensation value from the total propagation path length.

[0011] In one embodiment, the step of calculating the total propagation path length of the ultrasonic signal in the multi-core cable under test based on the actual propagation speed and the propagation time includes: Based on the signal propagation mode corresponding to the propagation time, determine the correspondence between the propagation time and the propagation path length; Based on the actual propagation speed, the propagation time, and the corresponding relationship, the total propagation path length of the ultrasonic signal in the multi-core cable under test is calculated.

[0012] Furthermore, to achieve the above objectives, this application also proposes a multi-core cable measuring device, which includes: An identification module is used to identify a valid signal in an ultrasonic signal that has traveled through a multi-core cable under test, and to determine the propagation time of the valid signal in the multi-core cable under test, wherein the valid signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal; The acquisition module is used to acquire the ambient temperature and, based on the core material of the multi-core cable under test, compensate and correct the propagation speed of the effective signal in the multi-core cable under test to obtain the actual propagation speed. The calculation module is used to determine the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and the preset path compensation value.

[0013] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the multi-core cable measurement method described above.

[0014] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the multi-core cable measurement method described above.

[0015] One or more technical solutions proposed in this application have at least the following technical effects: This application identifies a valid signal from ultrasonic signals propagating through a multi-core cable under test, determines the propagation time of the valid signal in the cable, and obtains the valid signal through signal characteristics of the corresponding source signal of the ultrasonic signal. It acquires the ambient temperature and, based on the core material of the multi-core cable, compensates for and corrects the propagation speed of the valid signal in the cable to obtain the actual propagation speed. Based on the actual propagation speed, the propagation time, and a preset path compensation value, it determines the length of the multi-core cable under test. In other words, this embodiment identifies a valid signal from ultrasonic signals by utilizing the signal characteristics of the corresponding source signal, solving the technical problems of traditional cable length measurement schemes, such as the lack of identifiable markers and the difficulty for the receiving end to accurately extract the target signal from a strong electromagnetic noise environment. It can accurately identify valid signals from interference signals, thereby significantly improving the anti-interference capability of the measurement process and ensuring the accuracy and reliability of signal identification. By acquiring ambient temperature and compensating for the propagation speed based on the core wire material, this method solves the technical problem in traditional cable length measurement schemes where sound speed fluctuates with temperature and the sound speed characteristics of cables with different materials differ significantly, leading to measurement accuracy relying on on-site calibration. Through the compensation mechanism, the ultrasonic propagation speed can be dynamically corrected based on real-time ambient temperature and cable core wire material, eliminating the influence of environmental factors on the measurement results and avoiding cumbersome on-site wave speed pre-calibration operations. This makes the measurement process simpler and more stable, and the measurement accuracy is not affected by changes in the external environment, significantly improving measurement accuracy and reducing the complexity of measurement operations. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the first embodiment of the multi-core cable measurement method of this application; Figure 2This is a schematic diagram of the structure of a handheld measuring host provided in Embodiment 1 of this application; Figure 3 This is a schematic diagram of a test cable conduction structure provided in Embodiment 1 of this application; Figure 4 This is a flowchart illustrating Embodiment 2 of the multi-core cable measurement method of this application. Figure 5 This is an ultrasonic coding timing diagram provided for the multi-core cable measurement method in the embodiments of this application; Figure 6 A simplified flowchart illustrating the multi-core cable measurement method provided in this application; Figure 7 This is a schematic diagram of the module structure of the multi-core cable measuring device according to an embodiment of this application.

[0019] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0021] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0022] The main solution of this application embodiment is as follows: Identify the effective signal from the ultrasonic signal propagating through the multi-core cable under test, determine the propagation time of the effective signal in the multi-core cable under test, wherein the effective signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal; acquire the ambient temperature, and compensate and correct the propagation speed of the effective signal in the multi-core cable under test according to the core material of the multi-core cable under test to obtain the actual propagation speed; determine the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and a preset path compensation value.

[0023] In this embodiment, for ease of description, the following description uses a multi-core cable measuring device as the execution subject.

[0024] Accurate measurement of the length of multi-core cables is a fundamental and crucial technical task in power system operation and maintenance, project completion acceptance, and cable production quality inspection. Currently, the pulse-reflection method (TDR) is the mainstream technique for measuring the length of power cables. This method involves transmitting an electrical pulse signal into the cable. When the signal encounters a point of impedance discontinuity (such as the cable end, joint, or fault point), it is reflected. By measuring the time difference between the transmitted and reflected pulses and combining this with the preset propagation speed of the signal in the cable, the length of the cable or the distance to the fault point can be calculated.

[0025] However, existing measurement schemes based on pulse-reflection measurement methods are hampered by several limitations when dealing with the precise measurement requirements of multi-core cables. These limitations stem from the variations in signal propagation speeds among power cables from different manufacturers and of different specifications, as well as the significant impact of ambient temperature variations on sound velocity. This results in measurement accuracy being highly dependent on on-site pre-calibration of wave velocity, making the process cumbersome and prone to human error. Furthermore, the lack of identifiable characteristic markers in traditional pulse signals makes them susceptible to strong electromagnetic noise interference in complex substation or underground utility tunnel environments. The receiving end struggles to accurately identify the target reflected signal from the mixed signals, ultimately leading to low measurement accuracy and cumbersome operation for multi-core cable length measurements.

[0026] This application provides a solution for identifying a valid signal from ultrasonic signals propagating through a multi-core cable under test, determining the propagation time of the valid signal in the cable, wherein the valid signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal; acquiring the ambient temperature, and compensating for and correcting the propagation speed of the valid signal in the multi-core cable under test based on the core material of the cable to obtain the actual propagation speed; and determining the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and a preset path compensation value. In other words, this embodiment of the application identifies a valid signal from an ultrasonic signal by using the signal characteristics of the source signal corresponding to the ultrasonic signal, solving the technical problems of traditional cable length measurement schemes, such as the lack of identifiable markers and the difficulty for the receiving end to accurately extract the target signal from a strong electromagnetic noise environment. It can accurately identify a valid signal from interference signals, thereby significantly improving the anti-interference capability of the measurement process and ensuring the accuracy and reliability of signal identification. By acquiring ambient temperature and compensating for the propagation speed based on the core wire material, this method solves the technical problem in traditional cable length measurement schemes where sound speed fluctuates with temperature and the sound speed characteristics of cables with different materials differ significantly, leading to measurement accuracy relying on on-site calibration. Through the compensation mechanism, the ultrasonic propagation speed can be dynamically corrected based on real-time ambient temperature and cable core wire material, eliminating the influence of environmental factors on the measurement results and avoiding cumbersome on-site wave speed pre-calibration operations. This makes the measurement process simpler and more stable, and the measurement accuracy is not affected by changes in the external environment, significantly improving measurement accuracy and reducing the complexity of measurement operations.

[0027] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer or personal computer, or a multi-core cable measuring device capable of performing the above functions. The following description uses a multi-core cable measuring device as an example to illustrate this embodiment and the subsequent embodiments.

[0028] Based on this, the embodiments of this application provide a method for measuring multi-core cables, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the multi-core cable measurement method of this application.

[0029] Specifically, the multi-core cable measuring device further includes a handheld measuring host and a test cable assembly connected to the handheld measuring host. The handheld testing host integrates a control unit, a transmitting module, a receiving module, a high-speed signal acquisition module, an interaction module, a power supply module, and a temperature sensor. The test cable assembly includes a first test cable and a second test cable, used to connect the first and second cores of the cable under test, respectively. See also... Figure 2 , Figure 2This is a schematic diagram of the structure of a handheld measuring host provided in Embodiment 1 of this application.

[0030] Furthermore, the control unit employs an STM32H743 microcontroller for full-module coordinated control, parameter initialization, sending start transmission signals to the transmitting module, receiving propagation time data, calculating compensation based on ambient temperature, and controlling data display and storage. The transmitting module is an independent integrated circuit board with two high-frequency signal outputs, electrically connected to the control unit and the high-speed signal acquisition module. After receiving the transmission signal from the control unit, it outputs two 3MHz±0.05MHz high-frequency sine wave signals (peak voltage 5-10V). One signal is transmitted to the pin of the ceramic pressure plate used for transmission, and the other is synchronously transmitted to the high-speed signal acquisition module as a timing trigger signal. The receiving module is an independent integrated circuit board with a built-in 2-4MHz bandpass filter and amplification circuit, electrically connected to the high-speed signal acquisition module. It receives the mV-level sine wave signal transmitted from the ceramic pressure plate, filters and amplifies it internally, and then transmits it to the high-speed signal acquisition module. The high-speed signal acquisition module is an independent integrated circuit board with two high-speed ADC inputs, an integrated FPGA, and peripheral circuitry. It operates at a sampling rate of 100MHz. After receiving the synchronization signal from the transmitting module, it records the transmission time t0. Subsequently, it receives the effective signal processed by the receiving module and records the reception time t1. It calculates the ultrasonic round-trip time ΔT = t1 - t0 and transmits it to the control unit. The interaction module consists of a 2.4-inch touchscreen with physical buttons, supporting measurement parameter display, historical data storage, and visual selection of copper / aluminum materials. The power supply module is a built-in 12V 5000mAh lithium battery. The temperature sensor, with a measurement range of -10℃ to 60℃, is electrically connected to the control unit and is used to acquire ambient temperature data to correct for ultrasonic propagation speed.

[0031] like Figure 2 As shown, the control unit sends a start trigger signal to the transmitting module, connects to the high-speed signal acquisition module via a communication interface, and is connected to a temperature sensor. The high-frequency sine wave signal output by the transmitting module is transmitted in two ways: one to the ceramic plate (for transmitting) in the first test cable, and the other to the interface of the high-speed signal acquisition module as the t0 timing trigger signal. The receiving module receives the mV-level signal from the ceramic plate (for receiving) in the second test cable, filters and amplifies it, and then outputs it to another input interface of the high-speed signal acquisition module. The power supply module outputs 12V power to power all modules. The handheld measuring unit has two built-in bidirectional transducer ceramic plates. The ceramic plates are made of PZT-5H piezoelectric ceramic material with a piezoelectric constant d. 33With a diameter of ≥550 pC / N, Curie temperature ≥180℃, a diameter of 8mm, a thickness of 2-3mm, and an operating frequency of 3MHz±0.05MHz, it can achieve bidirectional conversion between electrical signals and mechanical vibration signals. The test cable has a pre-fabricated elastic pre-compression structure that tightly presses the ceramic plate against the corresponding internal copper plate. The copper plate is welded to the conductive end of the test cable, forming a double-stable structure of "elastic pre-compression bonding + welding fixation." This structure ensures no relative movement or air gap between the ceramic plate and the copper plate, achieving lossless acoustic energy transmission. Furthermore, this fixed acoustic coupling is completed during the manufacturing stage, requiring no on-site bonding or fixing operations from the user.

[0032] Specifically, the test cable assembly includes a first test cable (transmitter side clamp) and a second test cable (receiver side clamp). Each test cable is 1.0m long with a double-layer shielded design and a shielding effectiveness of ≥80dB. The end is equipped with an elastic alligator clip with a conductive plating.

[0033] For details, see Figure 3 , Figure 3 This is a schematic diagram of a test cable conduction structure provided in Embodiment 1 of this application, as shown below. Figure 3 As shown, the handheld measuring unit 1 is connected to the first core wire 4 via the first test cable 2 and to the second core wire 5 via the second test cable 3. The A-end jumper 7 is detachably connected to the cable under test 6. The A-end jumper 7 is made of highly conductive copper alloy (conductivity ≥98%), with a total length of 0.2m. Both ends are equipped with elastic alligator clips, with an overall resistance <0.1Ω, a clamping pressure ≥5N, and a contact resistance <0.2Ω when clamping the core wire of the cable under test. This jumper is used to electrically connect the first core wire 4 and the second core wire 5 to form a closed conduction circuit.

[0034] Furthermore, during measurement, the operator first short-circuits the first core wire 4 and the second core wire 5 on the cable under test 6 using the A-end shorting wire 7. Then, at one end, the first core wire 4 and the second core wire 5 are clamped together using the first test cable 2 and the second test cable 3, respectively. The control unit activates the transmitting module, which outputs an coded ultrasonic signal. This signal is converted into mechanical vibration by the ceramic pressure plate inside the first test cable 2, propagates along a closed conduction loop, and is received by the ceramic pressure plate inside the second test cable 3, where it is converted into an electrical signal. The high-speed signal acquisition module records the time difference between transmission and reception. The control unit, combined with the ambient temperature collected by the temperature sensor, performs compensation and correction, deducts the preset path compensation value, and finally calculates the cable length.

[0035] In this embodiment, the multi-core cable measurement method includes steps S10 to S30: Step S10: Identify the effective signal from the ultrasonic signals propagating through the multi-core cable under test, and determine the propagation time of the effective signal in the multi-core cable under test. The effective signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal. It should be noted that this embodiment provides a multi-core cable measurement method, which can be applied to scenarios such as power grid operation and maintenance, project completion acceptance, and cable production quality inspection, for accurate measurement of the length of multi-core cables. Traditional reflection methods for measuring multi-core cables suffer from technical problems such as weak anti-interference capability, reliance on on-site wave velocity calibration, and measurement blind zones at short distances. This embodiment effectively solves these problems by introducing signal characteristics, compensation correction, and preset path compensation values, achieving high-precision, strong anti-interference, and blind-zone-free cable length measurement. Signal characteristics refer to the identifiable identifiers pre-assigned to the ultrasonic signal at the transmitting end. These are used to distinguish the ultrasonic signal from noise interference and clutter signals in the field environment at the receiving end. The effective signal refers to the signal segment in the original ultrasonic signal acquired from the receiving end that matches the signal characteristics after identification processing. The original signal actually acquired by the receiving end often includes the target ultrasonic signal propagating along a predetermined path, as well as noise and clutter signals introduced by the on-site electromagnetic environment. Therefore, by identifying and processing the signal to extract the valid signal for timing, the accuracy of the signal used in the cable length measurement process is ensured, and the influence of interference signals on the measurement results is eliminated, thereby guaranteeing the accuracy and reliability of the measurement. Propagation time refers to the total time it takes for an ultrasonic signal to travel from the transmitter into the cable under test, through the cable, and back to the receiver. The ultrasonic signal is injected into the first core wire of the cable under test, propagates along the first core wire to the second core wire, switches to the second core wire via the electrical connection between the first and second core wires, and then returns along the second core wire to be received. Therefore, the propagation time corresponds to the total time it takes for the signal to complete one round trip in a closed conduction loop.

[0036] Understandably, when acquiring ultrasonic signals propagating within the multi-core cable under test through a signal receiving channel, the original signal typically contains a large amount of interference due to strong electromagnetic noise in the environment. Therefore, based on signal characteristics, the original signal is decoded and processed. The receiving end decodes the original signal, identifying signal segments that match the signal characteristics. For example, when the signal characteristics are a preset coded sequence, the receiving end decodes the original signal and matches a signal segment consistent with the preset coded sequence. During the identification process, amplitude thresholding can be used to initially filter out low-amplitude noise, and then time-series matching can be used to accurately verify candidate signals, ensuring that the identified signal segments are consistent with the preset coded sequence in terms of bit length, symbol duration, and symbol value. After determining the identified signal segment as a valid signal, the arrival time of this valid signal is used as the reception time. Simultaneously, the transmitting end records the transmission time at the signal injection moment. The difference between the reception time and the transmission time yields the propagation time of the valid signal within the multi-core cable under test. By assigning signal characteristics to the ultrasound signal, the receiver can accurately determine the target signal based on these characteristics. The identification mechanism, which employs amplitude threshold filtering and timing matching, improves the accuracy and reliability of the identification.

[0037] In one feasible implementation, the multi-core cable under test includes at least a first core wire and a second core wire; the method further includes: The ultrasonic signal propagating through the multi-core cable under test is obtained by means of a preset measurement conduction loop, wherein the preset measurement conduction loop consists of the first core wire, a signal transmission channel between the first core wire and the second core wire, and the second core wire. The source signal enters the preset measurement conduction loop from the port of the first core wire, and after propagating in the preset measurement conduction loop, it is collected at the port of the second core wire to obtain the ultrasonic signal.

[0038] It should be noted that the preset measurement conduction loop refers to a signal transmission path specifically constructed for cable length measurement, consisting of the core wires of the cable under test. The core components of this preset measurement conduction loop include: the first core wire and the second core wire of the multi-core cable under test, and a signal transmission channel (such as a shorting tool) electrically connecting the first and second core wires at the second end of the cable. The source signal refers to the initial ultrasonic signal injected into the preset measurement conduction loop from the transmitting end of the measuring device. This signal is endowed with signal identification characteristics (such as a preset coding sequence) during transmission. The source signal enters the preset measurement conduction loop from the port (i.e., the first end) of the first core wire. Specifically, the electrical signal with preset identification characteristics is converted into ultrasonic waves by a pre-installed transmitting transducer within the first test cable and coupled into the first core wire.

[0039] Specifically, the first and second core wires are electrically connected via a signal transmission channel (such as a dedicated A-end shorting wire). This connects the two originally independent core wires at the far end, forming a signal transmission channel. In the first core wire of the multi-core cable under test, a first test cable and a second test cable, each with a pre-installed transducer, establish signal transmission channels with the first and second core wires, respectively. At this point, the pre-set measurement conduction loop, consisting of "transducer in the first test cable → first core wire → electrical connection at the second end → second core wire → transducer in the second test cable," is formally formed. The source signal, carrying signal identification characteristics, is injected into the pre-set measurement conduction loop from the port of the first core wire through the transmitting transducer in the first test cable. The source signal propagates along the first core wire within the multi-core cable under test, reaches the other end, is switched to the second core wire via the signal transmission channel, and then returns along the second core wire. After the source signal completes its propagation throughout the loop, it is collected by the receiving transducer in the second test cable at the port of the second core wire, yielding an ultrasonic signal containing propagation information.

[0040] Understandably, by pre-setting the measurement transmission circuit, a solid physical foundation is laid for subsequent high-precision measurements, and a convenient "clamp and measure" operation experience is achieved.

[0041] In one feasible implementation, the step of identifying a valid signal from the ultrasonic signals propagating through the multi-core cable under test and determining the propagation time of the valid signal in the multi-core cable under test includes steps S21-S22: Step S21: Decode the ultrasonic signal that has been transmitted through the multi-core cable under test and identify the signal segment that matches the signal characteristics; It should be noted that decoding refers to processing the received ultrasound signal, converting it into a recognizable and analyzable form, and extracting information related to the signal characteristics. A signal segment refers to a section of signal that matches the signal characteristics from a continuous ultrasound signal.

[0042] Understandably, the received ultrasound signal undergoes preprocessing to enhance the effective signal components and suppress noise interference. The signal is filtered by amplitude, retaining the portion exceeding a preset threshold. Then, the threshold-filtered portion is time-domain segmented, dividing the continuous signal into multiple symbol units according to a preset symbol duration. The amplitude characteristics of each symbol unit are extracted and compared with preset symbol values ​​to determine the corresponding symbol value (e.g., 0 or 1). The resulting symbol value sequence is then compared bit-by-bit with a preset encoding sequence to determine if they match. When the matching degree between the symbol value sequence of a signal segment and the preset encoding sequence reaches a preset requirement, that signal segment is identified as matching the signal characteristics and extracted.

[0043] Step S22: The signal segment is taken as the effective signal, and the propagation time is determined based on the transmission time of the ultrasonic signal and the reception time of the effective signal.

[0044] It should be noted that the transmission time refers to the instant the ultrasonic signal is injected into the multi-core cable under test from the transmitting end. The reception time refers to the instant the effective signal reaches the receiving end.

[0045] Understandably, using identified and confirmed signal segments as valid signals ensures that the signal used for timing is the target signal propagating along the predetermined path, avoiding timing errors caused by noise or interference signals being mistaken for the target signal. Employing a synchronous triggering mechanism to accurately record the transmission time and using the arrival time of the identified signal segment as the reception time ensures the accuracy of the timing start and end points, improving measurement reliability.

[0046] In one feasible implementation, the signal features include bit length features, symbol duration features, and a preset symbol sequence; The step of decoding the ultrasonic signal propagating through the multi-core cable under test and identifying the signal segment that matches the signal characteristics includes steps S31 to S35: Step S31: Perform amplitude threshold screening on the ultrasound signal, retain the signal portion that is greater than or equal to the preset amplitude, and obtain candidate signal segments; It should be noted that the bit length feature indicates the total number of bits that the valid signal should contain, the symbol duration feature indicates the time length occupied by each symbol unit, and the preset symbol sequence indicates the symbol value order of the valid signal (e.g., "110011"). By decoding the ultrasound signal and comparing it with the above three features, the target signal can be accurately identified. Amplitude threshold filtering refers to the process of initially filtering the original acquired signal based on the amplitude of the signal. Candidate signal segments refer to continuous signal segments whose amplitude exceeds the preset threshold after amplitude threshold filtering. The receiving end first digitizes the acquired original ultrasound signal to obtain a discrete sequence of sampling points. Then, the amplitude of this sequence is compared: all sampling points are traversed, and when multiple consecutive sampling points are found to have amplitudes greater than or equal to the preset amplitude threshold, the signal segment formed by these consecutive sampling points is extracted as a candidate signal segment; when the amplitude falls below the threshold, the segment extraction ends.

[0047] Step S32: Perform time-domain segmentation on the candidate signal segment based on the symbol duration feature to obtain symbol units; It should be noted that time-domain segmentation refers to the process of dividing a continuous candidate signal segment into multiple independent units according to a preset time length. A symbol unit is a signal segment within a candidate signal segment corresponding to a single symbol time. Each symbol unit contains complete symbol information, and its corresponding numerical value (0 or 1) is determined by analyzing its amplitude characteristics. For each candidate signal segment, its starting time point is first determined. Then, using this starting point as a reference, the entire candidate signal segment is divided into multiple continuous symbol units by sequentially shifting according to the symbol duration characteristics. The length of each symbol unit is consistent with the symbol duration characteristics, and adjacent units are seamlessly connected. After segmentation, the symbol unit sequence of the candidate signal segment is obtained.

[0048] Step S33: Determine the symbol value corresponding to the symbol unit based on the amplitude characteristics of the symbol unit, and obtain the symbol value sequence of the candidate signal segment; It should be noted that amplitude characteristics refer to the statistical properties of the signal amplitude within a symbol unit, such as average amplitude, peak amplitude, or integral energy. Since coded signals typically employ amplitude modulation, different symbol values ​​(such as "1" and "0") correspond to different amplitude levels (e.g., "1" corresponds to high amplitude, and "0" corresponds to low amplitude). Therefore, the symbol value can be deduced by analyzing the amplitude characteristics. A symbol value is the basic unit in binary encoding, typically taking the value 0 or 1. A symbol value sequence is a sequence formed by arranging the symbol values ​​of all symbol units in a candidate signal segment in chronological order.

[0049] Step S34: Determine whether the total number of bits in the symbol value sequence of the candidate signal segment is consistent with the bit feature, and whether the symbol value sequence matches the preset symbol sequence; It should be noted that the total number of bits refers to the length of the symbol value sequence of the candidate signal segment, that is, the number of symbols contained in the segment. The bit-number feature is used to specify the total number of symbols that a valid signal should have. The length of the symbol value sequence of the candidate signal segment is calculated, i.e., its total number of bits. This total number of bits is compared with the preset bit-number feature: if they are inconsistent, it means that the length of the candidate signal segment does not meet the requirements and can be directly determined as invalid, without further comparison; if they are consistent, the next step of matching is performed. The symbol value sequence of the candidate signal segment is compared bit by bit with the preset symbol sequence. During the comparison, the symbol values ​​can be checked bit by bit to see if they are the same. If all bits are the same, it is determined to be a complete match.

[0050] Step S35: Candidate signal segments that simultaneously satisfy the bit feature and match the preset symbol sequence are identified as signal segments that match the signal feature.

[0051] It should be noted that when a candidate signal segment simultaneously satisfies the bit length characteristic and symbol sequence matching condition, the candidate signal segment is marked as a signal segment that matches the signal characteristics, and this signal segment is the final valid signal.

[0052] Understandably, by using amplitude threshold filtering, the final effective signal is ensured to be consistent with the signal characteristics in terms of length and content, thus guaranteeing the accuracy of timing. Because the recognition process has multiple safeguards, it can stably lock onto the target signal even in environments with strong interference, significantly improving the accuracy and reliability of ultrasonic signal recognition in complex electromagnetic environments.

[0053] Step S20: Obtain the ambient temperature, and based on the core material of the multi-core cable under test, compensate and correct the propagation speed of the effective signal in the multi-core cable under test to obtain the actual propagation speed. It should be noted that ambient temperature refers to the temperature of the measurement site. Because the propagation speed of ultrasonic signals in metallic conductors is temperature-sensitive, temperature changes can significantly alter the sound velocity, thus affecting measurement accuracy. Therefore, it is necessary to acquire the ambient temperature of the measurement site in real time as an input parameter for subsequent compensation. The ambient temperature is acquired in real time by a built-in temperature sensor located within the handheld measurement unit. Core wire material refers to the material type of the conductive core wires inside the multi-core cable being measured, primarily copper and aluminum. Different cable materials have different ultrasonic propagation speeds, and the variation of sound velocity with temperature also differs. For example, the reference sound velocity of a copper core cable at 25℃ is approximately 5010 m / s, while that of an aluminum core cable is approximately 6320 m / s. The temperature influence coefficient for copper is approximately 0.001, and for aluminum, it is approximately 0.0012. Core wire material information can be manually selected by the user through an interactive module (e.g., selecting "copper" or "aluminum" via the touchscreen). Compensation correction refers to the process of adjusting the ultrasonic propagation speed based on real-time ambient temperature and core wire material information to eliminate the influence of temperature changes on the measurement results. By compensating and correcting the propagation speed, the ultrasonic propagation speed can adaptively follow changes in ambient temperature, thereby eliminating the influence of temperature factors on measurement accuracy and achieving stable measurement.

[0054] Understandably, by acquiring the ambient temperature and compensating for the propagation speed of the effective signal in the multi-core cable under test based on the core material, the technical problem of reduced measurement accuracy caused by temperature changes and material differences in traditional measurement schemes is effectively solved. This achieves precise adaptation to copper and aluminum core multi-core cables, laying a solid foundation for subsequent high-precision length measurement.

[0055] In one feasible implementation, the step of acquiring the ambient temperature and compensating and correcting the propagation speed of the effective signal in the multi-core cable under test according to the core material of the multi-core cable under test to obtain the actual propagation speed includes steps S41~S43: Step S41: Obtain the core material information of the multi-core cable under test; It should be noted that the core wire material information refers to the data on the type of conductive core wire material inside the multi-core cable being tested, including copper core and aluminum core.

[0056] Step S42: Based on the core wire material information, determine the reference sound velocity and temperature influence coefficient corresponding to the core wire material information; It should be noted that the reference sound velocity refers to the speed at which an ultrasonic signal propagates through the core of a cable made of a specific material at a preset reference temperature (usually 25°C). The reference sound velocity is a baseline value for temperature compensation correction, reflecting the acoustic characteristics of the cable material under standard conditions. For example, the reference sound velocity for copper core cables is 5010 m / s (25°C), and for aluminum core cables it is 6320 m / s (25°C). The temperature influence coefficient is a parameter characterizing the degree to which the ultrasonic propagation speed changes with temperature.

[0057] Step S43: Calculate the actual propagation speed of the effective signal at the ambient temperature based on the ambient temperature, the reference sound speed, and the temperature influence coefficient.

[0058] It should be noted that the actual propagation speed refers to the true propagation rate of the ultrasonic signal in the tested cable core at the current ambient temperature, obtained after compensation and correction. This speed value has eliminated the influence of ambient temperature changes and can accurately reflect the signal propagation characteristics under current conditions. Since the propagation speed of ultrasonic signals in metallic conductors decreases with increasing temperature, and this change is linear within a certain temperature range, the actual propagation speed can be expressed as the reference sound speed multiplied by a correction factor related to the temperature difference.

[0059] Specifically, the ambient temperature T is collected in real time by a temperature sensor. m Simultaneously, the reference sound velocity v_ref and temperature influence coefficient α are obtained. The temperature difference ΔT = T between the current ambient temperature and the reference temperature is calculated. m -T_ref. Then, the actual propagation speed is calculated according to the compensation formula. The actual sound speed is equal to the reference sound speed multiplied by a correction factor related to the temperature difference. Since the sound speed decreases with increasing temperature, the correction factor is usually expressed as (1-α×ΔT). Therefore, the compensated actual sound speed v t =v_ref×(1-α×ΔT)

[0060] Understandably, by configuring different reference sound velocities and temperature influence coefficients for different materials, this method can be widely applied to measurement scenarios for various multi-core cables. Traditional cable length measurement schemes require operators to pre-calibrate the wave velocity for each cable, which is complex and prone to human error. Through built-in material-specific parameters and temperature compensation correction, the actual sound velocity under the current ambient temperature conditions can be automatically calculated. Furthermore, the compensated actual propagation speed eliminates the dual influence of ambient temperature and material differences, ensuring high accuracy of measurement results under various complex measurement conditions and achieving precise adaptation to multi-core cables.

[0061] Step S30: Determine the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and the preset path compensation value.

[0062] It should be noted that propagation time refers to the total time it takes for the effective signal to complete one round trip in the multi-core cable under test. The preset path compensation value is a fixed length compensation amount pre-set and stored in the measuring device. This compensation value is used to offset the fixed path length contribution introduced by the signal injection and receiving channels (such as test cables and alligator clips) and the signal transmission channel between the first and second cores (such as shorting tools). In actual measurements, the actual propagation path of the ultrasonic signal includes not only the cores of the cable under test but also the connecting parts from the transducer to the cable cores (such as the internal copper plate of the test cable and alligator clips) and the shorting tools used to short the two cores. These external accessories introduce a fixed path length independent of the cable length. Failure to subtract this will lead to an overestimation of the measurement result, introducing systematic error.

[0063] Specifically, the control unit calls the ambient temperature Tm collected by the temperature sensor and substitutes it into the sound velocity temperature compensation formula corresponding to the material to calculate the actual sound velocity v. t Based on v t Substituting ΔT into the length calculation formula (L=v) t ×ΔT / 2-L 补 The actual length L of the cable is obtained, where L 补 It is an inherent constant used to compensate for the fixed length of the transmitter clamp, receiver clamp, and shorting wire at end A, as well as inherent structural errors in the circuit.

[0064] In one feasible implementation, the step of determining the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and the preset path compensation value includes steps S51-S52: Step S51: Calculate the total propagation path length of the ultrasonic signal in the multi-core cable under test based on the actual propagation speed and the propagation time; It should be noted that the total propagation path length refers to the distance that the ultrasonic signal travels from the time of transmission to the time of reception.

[0065] Step S52: Subtract the preset path compensation value from the total propagation path length to obtain the length of the multi-core cable under test.

[0066] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 4 , Figure 4 This is a flowchart illustrating Embodiment 2 of the multi-core cable measurement method of this application. The step of calculating the total propagation path length of the ultrasonic signal in the multi-core cable under test based on the actual propagation speed and the propagation time includes steps A11-A12: Step A11: Determine the correspondence between the propagation time and the propagation path length based on the signal propagation mode corresponding to the propagation time; It should be noted that the signal propagation mode refers to the way the ultrasonic signal propagates in the multi-core cable under test, including whether the signal is emitted from one end of the cable and received from the same end (single-end reflection mode or round-trip propagation mode), or emitted from one end and received from the other end (transmission mode). Different propagation modes correspond to different mathematical relationships between propagation time and cable length. In this embodiment, the ultrasonic signal adopts a "single-end transmission and reception, round-trip propagation" working mode, that is, the signal is injected from the first end of the cable under test, propagates along the first core wire to the second end, switches to the second core wire through the electrical connection (short circuit) at the second end, and then returns to the first end along the second core wire to be received. This mode makes full use of the structural feature of multi-core cables having at least two core wires, and constructs a closed loop by shorting at the far end, so that the signal can be conducted along the entire metal conductor and return to the same end. The correspondence between propagation time and propagation path length refers to the mathematical relationship between propagation time and propagation path length under a given signal propagation mode. Signal propagation modes include round-trip propagation mode, transmission propagation mode, and single-end reflection propagation mode. In round-trip propagation mode, the ultrasonic signal is triggered at the transmitting end, propagates to the far end, and returns to the same receiving end. In this mode, the propagation time corresponds to the time it takes for the ultrasonic signal to travel twice the cable length plus the fixed path of external accessories. In transmission propagation mode, the signal is transmitted from one end of the cable and received from the other. In this mode, the propagation time corresponds to the time it takes for the signal to travel one time the cable length plus the fixed path of external accessories. In single-end reflection mode, the signal is transmitted from one end of the cable and reflects back to the same end if it encounters an open circuit or short circuit at the other end. In this mode, the propagation time corresponds to the time it takes for the signal to travel twice the cable length (excluding the fixed path of external accessories).

[0067] Specifically, the measuring device and method in this embodiment are specifically designed for multi-core cables, constructing a closed loop through a remote short circuit, thus employing a "single-end transmission and reception, round-trip propagation" working mode. This mode information can be pre-programmed into the control program of the measuring host, eliminating the need for reconfirmation during each measurement. After determining the propagation mode, the correspondence between propagation time and propagation path length is determined based on the characteristics of this mode. In the round-trip propagation mode, the propagation time is the total time taken for the ultrasonic signal to travel from transmission to reception. This time includes the time for the signal to travel back and forth within the cable cores, as well as the time for the signal to propagate through external accessories (internal copper plates of the test cable, alligator clips, shorting tools). After determining the correspondence, the actual cable length is calculated based on the corrected propagation speed and propagation time.

[0068] Step A12: Based on the actual propagation speed, the propagation time, and the corresponding relationship, calculate the total propagation path length of the ultrasonic signal in the multi-core cable under test.

[0069] Understandably, by clearly defining the signal propagation mode and accurately calculating the total propagation path length based on the actual propagation speed and propagation time, the method provides precise intermediate parameters for determining the actual length of the multi-core cable under test, further improving the high-precision measurement method for the entire link.

[0070] For example, to help understand the implementation flow of the multi-core cable measurement method obtained by combining this embodiment with the above embodiment one, please refer to... Figure 6 , Figure 6 A simplified flowchart illustrating the multi-core cable measurement method provided in this application is as follows: Before starting the measurement, the operator has completed the preparations described in the second embodiment: at the first end of the multi-core cable under test, the first and second core wires are clamped by the first and second test cables respectively to establish a signal transmission channel. At the second end of the multi-core cable under test, the first and second core wires are electrically connected using a shorting wire at end A to form a closed conduction loop. After the preparations are complete, the operator starts the measurement program through the interactive module (such as a touch screen or physical button) of the handheld measurement host. After receiving the start command, the control unit begins to execute the subsequent measurement steps. The control unit sends a "start transmission" trigger signal to the transmitting module. The transmitting module responds to the trigger signal and generates an ultrasonic electrical signal with signal characteristics. The transmitting module outputs two 3MHz±0.05MHz high-frequency sinusoidal electrical signals (peak voltage 5-10V), which carry the preset encoding sequence "110011". The preset encoding sequence "110011" has the following characteristics: a total of 6 bits, with the first and last bits both being 1, and each bit having a duration of 10μs, resulting in a total duration of 60μs for the entire encoded signal. These characteristics include the number of bits (6 bits), the duration of the code (10μs), and the preset code sequence (110011). Of the two signals output by the transmitting module, one is transmitted via the first test cable to the pin of the transmitting ceramic plate to drive the generation of ultrasonic waves, while the other is synchronously transmitted to the high-speed signal acquisition module as a timing trigger signal for the transmission. Upon receiving the high-frequency sinusoidal electrical signal, the pin of the transmitting ceramic plate generates mechanical vibration, radiating ultrasonic waves. The ultrasonic waves propagate along a preset closed metal conduction loop. After propagating along the closed conduction loop to the receiving end, the ultrasonic waves are captured by the receiving ceramic plate. The receiving module receives the weak mV-level electrical signal from the receiving ceramic plate and then filters and amplifies it. The high-speed signal acquisition module (100MHz sampling rate, 12-bit resolution) simultaneously receives two inputs: a trigger signal synchronously output from the transmitting module to record the transmission time, and a processed signal from the receiving module to receive and identify valid signals. It records the transmission start time and reception time, verifies the characteristics of the received signal, calculates the ultrasonic round-trip time, and transmits the round-trip time to the control unit. The control unit calculates the actual cable length using the transmission time and cable material, applying length calculation formulas, temperature compensation, and preset path compensation values. The control unit outputs the calculated actual cable length to the interactive module for display. Simultaneously, the control unit judges the validity of the measurement results. If the encoding is successfully identified and the propagation time is within a reasonable range (corresponding to a measurement range of 20m-3km cable), the measurement is considered valid, and the touchscreen displays parameters such as cable length, error range, and ambient temperature, and automatically stores the data. If identification fails or the propagation time exceeds a reasonable range, a prompt appears: "Check probe connection, wiring, or cable integrity," allowing operators to troubleshoot the problem.

[0071] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the multi-core cable measurement method of this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0072] This application also provides a multi-core cable measuring device; please refer to... Figure 7 The multi-core cable measuring device includes: The identification module 10 is used to identify a valid signal in the ultrasonic signal that has been transmitted through the multi-core cable under test, and to determine the propagation time of the valid signal in the multi-core cable under test, wherein the valid signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal; The acquisition module 20 is used to acquire the ambient temperature and, based on the core material of the multi-core cable under test, compensate and correct the propagation speed of the effective signal in the multi-core cable under test to obtain the actual propagation speed. The calculation module 30 is used to determine the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and the preset path compensation value.

[0073] Optionally, the identification module 10 is further configured to: The ultrasonic signal propagating through the multi-core cable under test is obtained by means of a preset measurement conduction loop, wherein the preset measurement conduction loop consists of the first core wire, a signal transmission channel between the first core wire and the second core wire, and the second core wire. The source signal enters the preset measurement conduction loop from the port of the first core wire, and after propagating in the preset measurement conduction loop, it is collected at the port of the second core wire to obtain the ultrasonic signal.

[0074] Optionally, the identification module 10 is further configured to: The ultrasonic signal propagating through the multi-core cable under test is decoded to identify signal segments that match the signal characteristics. The signal segment is taken as the effective signal, and the propagation time is determined based on the transmission time of the ultrasonic signal and the reception time of the effective signal.

[0075] Optionally, the identification module 10 is further configured to: The ultrasonic signal is subjected to amplitude threshold screening, and the signal portion with an amplitude greater than or equal to a preset value is retained to obtain candidate signal segments; Based on the symbol duration feature, the candidate signal segment is time-domain segmented to obtain symbol units; Based on the amplitude characteristics of the symbol unit, the symbol value corresponding to the symbol unit is determined, and the symbol value sequence of the candidate signal segment is obtained; Determine whether the total number of bits in the symbol value sequence of the candidate signal segment is consistent with the bit feature, and whether the symbol value sequence matches the preset symbol sequence; Candidate signal segments that simultaneously satisfy the bit feature and match the preset symbol sequence are identified as signal segments that match the signal feature.

[0076] Optionally, the acquisition module 20 is further configured to: Obtain the core material information of the multi-core cable under test; Based on the core wire material information, determine the reference sound velocity and temperature influence coefficient corresponding to the core wire material information; Based on the ambient temperature, the reference sound velocity, and the temperature influence coefficient, the actual propagation speed of the effective signal at the ambient temperature is calculated.

[0077] Optionally, the computing module 30 is further configured to: Calculate the total propagation path length of the ultrasonic signal in the multi-core cable under test based on the actual propagation speed and the propagation time; The length of the multi-core cable under test is obtained by subtracting the preset path compensation value from the total propagation path length.

[0078] Optionally, the computing module 30 is further configured to: Based on the signal propagation mode corresponding to the propagation time, determine the correspondence between the propagation time and the propagation path length; Based on the actual propagation speed, the propagation time, and the corresponding relationship, the total propagation path length of the ultrasonic signal in the multi-core cable under test is calculated.

[0079] The multi-core cable measuring device provided in this application, employing the multi-core cable measuring method described in the above embodiments, can solve the technical problems of low measurement accuracy and cumbersome operation in traditional cable length measuring schemes. Compared with the prior art, the beneficial effects of the multi-core cable measuring device provided in this application are the same as those of the multi-core cable measuring method described in the above embodiments, and other technical features in the multi-core cable measuring device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0080] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0081] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0082] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to perform the multi-core cable measurement method described in the above embodiments.

[0083] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0084] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0085] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0086] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0087] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described multi-core cable measurement method. This solves the technical problems of low measurement accuracy and cumbersome operation in traditional cable length measurement schemes. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the multi-core cable measurement method provided in the above embodiments, and will not be repeated here.

[0088] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the multi-core cable measurement method described above.

[0089] The computer program product provided in this application can solve the technical problems of low measurement accuracy and cumbersome operation in traditional cable length measurement schemes. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the multi-core cable measurement method provided in the above embodiments, and will not be repeated here.

[0090] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for measuring multi-core cables, characterized in that, The multi-core cable measurement method includes: The effective signal is identified from the ultrasonic signals propagating through the multi-core cable under test, and the propagation time of the effective signal in the multi-core cable under test is determined. The effective signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal. The ambient temperature is obtained, and the propagation speed of the effective signal in the multi-core cable under test is compensated and corrected according to the core material of the multi-core cable under test to obtain the actual propagation speed. The length of the multi-core cable under test is determined based on the actual propagation speed, the propagation time, and the preset path compensation value.

2. The multi-core cable measurement method as described in claim 1, characterized in that, The multi-core cable under test includes at least a first core wire and a second core wire; the method further includes: The ultrasonic signal propagating through the multi-core cable under test is obtained by means of a preset measurement conduction loop, wherein the preset measurement conduction loop consists of the first core wire, a signal transmission channel between the first core wire and the second core wire, and the second core wire. The source signal enters the preset measurement conduction loop from the port of the first core wire, and after propagating in the preset measurement conduction loop, it is collected at the port of the second core wire to obtain the ultrasonic signal.

3. The multi-core cable measurement method as described in claim 1, characterized in that, The step of identifying a valid signal from the ultrasonic signals propagating through the multi-core cable under test and determining the propagation time of the valid signal in the multi-core cable under test includes: The ultrasonic signal propagating through the multi-core cable under test is decoded to identify signal segments that match the signal characteristics. The signal segment is taken as the effective signal, and the propagation time is determined based on the transmission time of the ultrasonic signal and the reception time of the effective signal.

4. The multi-core cable measurement method as described in claim 3, characterized in that, The signal features include bit length features, symbol duration features, and preset symbol sequences; The step of decoding the ultrasonic signal propagating through the multi-core cable under test and identifying the signal segment that matches the signal characteristics includes: The ultrasonic signal is subjected to amplitude threshold screening, and the signal portion with an amplitude greater than or equal to a preset value is retained to obtain candidate signal segments; Based on the symbol duration feature, the candidate signal segment is time-domain segmented to obtain symbol units; Based on the amplitude characteristics of the symbol unit, the symbol value corresponding to the symbol unit is determined, and the symbol value sequence of the candidate signal segment is obtained; Determine whether the total number of bits in the symbol value sequence of the candidate signal segment is consistent with the bit feature, and whether the symbol value sequence matches the preset symbol sequence; Candidate signal segments that simultaneously satisfy the bit feature and match the preset symbol sequence are identified as signal segments that match the signal feature.

5. The multi-core cable measurement method as described in claim 1, characterized in that, The steps of acquiring the ambient temperature and compensating for and correcting the propagation speed of the effective signal in the multi-core cable under test according to the core material of the multi-core cable under test to obtain the actual propagation speed include: Obtain the core material information of the multi-core cable under test; Based on the core wire material information, determine the reference sound velocity and temperature influence coefficient corresponding to the core wire material information; Based on the ambient temperature, the reference sound velocity, and the temperature influence coefficient, the actual propagation speed of the effective signal at the ambient temperature is calculated.

6. The multi-core cable measurement method as described in claim 1, characterized in that, The step of determining the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and the preset path compensation value includes: Calculate the total propagation path length of the ultrasonic signal in the multi-core cable under test based on the actual propagation speed and the propagation time; The length of the multi-core cable under test is obtained by subtracting the preset path compensation value from the total propagation path length.

7. The multi-core cable measurement method as described in claim 6, characterized in that, The step of calculating the total propagation path length of the ultrasonic signal in the multi-core cable under test based on the actual propagation speed and the propagation time includes: Based on the signal propagation mode corresponding to the propagation time, determine the correspondence between the propagation time and the propagation path length; Based on the actual propagation speed, the propagation time, and the corresponding relationship, the total propagation path length of the ultrasonic signal in the multi-core cable under test is calculated.

8. A multi-core cable measuring device, characterized in that, The multi-core cable measuring device includes: An identification module is used to identify a valid signal in an ultrasonic signal that has traveled through a multi-core cable under test, and to determine the propagation time of the valid signal in the multi-core cable under test, wherein the valid signal is obtained by identifying the signal characteristics of the source signal corresponding to the ultrasonic signal; The acquisition module is used to acquire the ambient temperature and, based on the core material of the multi-core cable under test, compensate and correct the propagation speed of the effective signal in the multi-core cable under test to obtain the actual propagation speed. The calculation module is used to determine the length of the multi-core cable under test based on the actual propagation speed, the propagation time, and the preset path compensation value.

9. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the multi-core cable measurement method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the multi-core cable measurement method as described in any one of claims 1 to 7.

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