Underwater high-frequency anti-interference cable and transmission method

Abstract

The application relates to the underwater cable technical field, in particular to an underwater high-frequency anti-interference cable and a transmission method, which comprise, from inside to outside, a core transmission layer, a middle shielding and isolating layer, a processing layer, an outer protective structure and a pressure balancing system; the core transmission layer comprises a center conductor group, a power transmission line and a control signal line; the center conductor group comprises four pairs of differential transmission lines; each pair of differential transmission lines comprises an inner conductor, an insulating layer wrapped outside the inner conductor and an outer conductor arranged outside the insulating layer; and each pair of differential transmission lines is twisted at a preset pitch. The application can bear high-frequency data signal transmission and simultaneously meet the power supply and control signal transmission requirements.

Description

Technical Field

[0001] This invention relates to the field of underwater cable technology, and in particular to an underwater high-frequency anti-interference cable and transmission method. Background Technology

[0002] With the development of marine exploration, underwater robots, and submarine communication networks, underwater cables need to undertake high-frequency (tens of MHz to several GHz) high-capacity data transmission tasks. Traditional underwater cables mainly focus on physical protection, and have the following prominent problems when facing high-frequency signal transmission: high-frequency signals attenuate severely over long distances, lack segmented compensation capabilities, leading to signal quality degradation; the simple shielding structure is insufficient to suppress complex underwater electromagnetic interference (especially common-mode interference), affecting signal integrity; changes in deep-water pressure can easily deform the internal structure, causing characteristic impedance drift and reducing long-term reliability; lack of adaptive processing capabilities makes it unable to cope with dynamically changing interference environments; and joints are prone to sealing failure and impedance mismatch.

[0003] Existing improvement solutions, such as optimizing shielding materials or enlarging the ends, can only partially improve single problems and have not yet systematically integrated high-performance shielding, distributed intelligent processing, pressure adaptation, and highly reliable connection technologies. Therefore, there is an urgent need for a cable solution that can simultaneously overcome the above-mentioned shortcomings and meet the comprehensive requirements of modern underwater high-frequency transmission. Summary of the Invention

[0004] To solve the above problems, the present invention provides an underwater high-frequency anti-interference cable and transmission method that can handle high-frequency data signal transmission and simultaneously meet the requirements for power supply and control signal transmission.

[0005] The technical solution adopted in this invention is: an underwater high-frequency anti-interference cable, comprising, from the inside out: a core transmission layer, an intermediate shielding and isolation layer, a processing layer, an outer protective structure, and a pressure balancing system. The core transmission layer includes a central conductor group, power transmission lines, and control signal lines. The central conductor group includes four pairs of differential transmission lines. Each pair of differential transmission lines includes an inner conductor, an insulation layer covering the outside of the inner conductor, and an outer conductor disposed outside the insulation layer. Each pair of differential transmission lines is twisted at a preset pitch. The intermediate shielding and isolation layer includes a first shielding layer and a first isolation layer sequentially disposed outside the core transmission layer. The cable comprises a first layer, a second shielding layer, and a second isolation layer; the processing layer includes multiple signal processing modules spaced apart along the cable length and an active anti-interference circuit electrically connected to the signal processing modules. The signal processing modules are used to perform spectrum analysis and interference detection on the high-frequency signals transmitted by the central conductor group, and the active anti-interference circuit is used to suppress the detected interference signals; the outer protective structure includes an inner sheath, a reinforcing layer, and an outer sheath, with the outer side of the outer sheath for contact with the underwater environment; the pressure balancing system includes a hydrophobic filling medium disposed inside the cable and a pressure compensation structure disposed at the cable joint;

[0006] The signal processing module is used to adaptively process the transmitted signal in the 50MHz~1GHz frequency band to improve the underwater high-frequency signal transmission capability and anti-interference performance.

[0007] A further improvement to the above scheme is that the inner conductor is silver-plated annealed copper wire, the outer conductor is tin-plated copper braided layer, the insulation layer is foamed polytetrafluoroethylene layer, and the stranding pitch of the differential transmission line is 15~25mm.

[0008] A further improvement to the above scheme is that the first shielding layer is an aluminum foil wrapping layer, the first isolation layer is a polyester tape wrapping layer, the second shielding layer is a tin-plated copper wire braided layer, and the second isolation layer is a water-blocking tape layer.

[0009] A further improvement to the above scheme is that the signal processing module includes a frequency adaptive processing unit, a real-time spectrum analysis unit, an interference detection unit, and an adaptive filtering unit. The frequency adaptive processing unit is used to select the operating sub-frequency band with the highest signal-to-noise ratio based on the spectrum analysis results, and the adaptive filtering unit is used to adjust the filtering parameters based on the interference detection results. The signal processing module is installed every 50 meters along the length of the cable and is connected to the core transmission layer via a flexible printed circuit board.

[0010] A further improvement to the above scheme is that the active anti-interference circuit includes a common-mode choke, a current compensation generator, and an EMI filter. The common-mode choke is used to suppress common-mode interference, the current compensation generator is used to inject reverse compensation current, and the EMI filter is used to filter out electromagnetic interference signals within a preset frequency band.

[0011] A further improvement to the above scheme is that the inner sheath is a modified polyurethane layer, the reinforcing layer is an aramid fiber braided layer, the outer sheath is a polyamide-polyurethane composite elastomer layer, and the outer sheath contains at least two of the following: anti-biofouling additives, anti-hydrolysis stabilizers, and anti-ultraviolet absorbers.

[0012] A further improvement to the above scheme is that the hydrophobic filling medium is silicone grease, and the pressure compensation structure is a pressure compensation membrane installed at the cable joint to balance the internal and external water pressure of the cable.

[0013] A further improvement to the above solution is that it also includes an underwater pluggable connector, which includes a sealing structure, an electrical connection structure, and a smart interface. The sealing structure includes a primary seal and a secondary seal. The electrical connection structure includes impedance matching contacts. The smart interface includes a microcontroller for storing cable parameters and historical data.

[0014] A further improvement to the above scheme is that the main sealing element is an O-ring, the secondary sealing element is a potting resin layer, the impedance matching contact is a gold-plated contact, and the characteristic impedance of the underwater pluggable connector in the 50MHz~1GHz frequency band is 50Ω±2%.

[0015] An underwater high-frequency anti-interference transmission method based on the aforementioned underwater high-frequency anti-interference cable includes the following steps: S1. The signal processing module performs a spectrum scan on the 50MHz~1GHz operating frequency band; the period of the spectrum scan is any preset period from 100ms to 5min, which is set according to the channel stability of the current application scenario. S2. Identify the frequency bands and intensity of interference sources based on the spectrum scanning results; S3. Select at least one sub-frequency band with the highest signal-to-noise ratio from the operating frequency band as the current transmission frequency band; S4. Adaptively adjust the transmit power, modulation scheme, and coding rate according to the selected transmission frequency band; the modulation scheme is one of QPSK, 16QAM, or 64QAM, and the coding rate is one of 1 / 2, 2 / 3, 3 / 4, or 5 / 6. S5. During signal transmission, the active anti-interference circuit suppresses common-mode interference and electromagnetic interference; forward error correction coding and interleaving coding are performed on the transmitted signal, and channel estimation is performed based on pilot symbols to reduce the bit error rate and improve the stability of underwater high-frequency transmission. S6. During the transmission process, steps S1 to S5 are periodically repeated to dynamically adjust the high-frequency transmission parameters.

[0016] A further improvement to the above scheme is that the signal transmission adopts OFDM transmission mode, with 256 subcarriers, a subcarrier spacing of 15.625kHz, and a cyclic prefix is ​​set to reduce the impact of multipath interference.

[0017] The beneficial effects of this invention are: Compared to existing cables, the underwater high-frequency anti-interference cable of this invention integrates differential transmission lines, power transmission lines, and control signal lines in the core transmission layer, and combines a multi-layer shielding and isolation structure, enabling the cable to not only carry out high-frequency data signal transmission, but also simultaneously meet the power supply and control signal transmission requirements. Therefore, it is suitable for application scenarios that require multi-signal composite transmission, such as underwater detection equipment, underwater robots, underwater sensing systems, and underwater communication nodes.

[0018] This invention, through the combination of a first shielding layer, a first isolation layer, a second shielding layer, and a second isolation layer, can form hierarchical shielding and interlayer isolation for the core transmission layer, reducing the impact of external electromagnetic interference, high-frequency crosstalk, and common-mode noise on the transmitted signal, while suppressing the mutual coupling between different signal channels, thereby improving the stability and integrity of high-frequency signal transmission.

[0019] This invention arranges multiple signal processing modules at intervals along the cable length, enabling segmented processing and compensation for bandwidth attenuation, signal distortion, and local interference that occur during long-distance underwater transmission. Compared to solutions that rely solely on centralized processing at the ends, this structure reduces cumulative distortion in long-distance high-frequency transmission, improving signal reception quality and link reliability.

[0020] The signal processing module of this invention includes an active anti-interference circuit, which can filter, suppress, compensate, or adjust parameters of the target frequency band based on the detected interference characteristics. Therefore, even in environments near marine platform equipment, motor drive equipment, sonar equipment, and other strong interference sources, this invention can still maintain good communication quality and improve adaptability to complex underwater electromagnetic environments.

[0021] This invention combines a hydrophobic filling medium with a pressure compensation structure to buffer the squeezing effect of external pressure changes on the internal structure of the cable in underwater environments, especially at greater depths. This reduces deformation, loosening, or performance drift of the sheath, shielding layer, and internal modules caused by pressure differentials, thereby improving the reliability of the cable during long-term service.

[0022] This invention provides a composite protective structure consisting of an inner sheath, a reinforcing layer, and an outer sheath. The inner sheath provides primary protection for the internal transmission and shielding components, the reinforcing layer enhances the cable's tensile, bending, and impact resistance, and the outer sheath protects against seawater erosion, external wear, and biological adhesion, thereby improving the cable's durability in complex underwater conditions.

[0023] This invention can be further used in conjunction with an underwater pluggable connector structure to form a reliable connection between the cable and external equipment, while maintaining the continuity of the overall seal and shielding, facilitating the installation, replacement and maintenance of underwater equipment, and reducing the difficulty of system deployment.

[0024] The number of differential transmission line pairs, the spacing between signal processing modules, the shielding material, the sheath material, and the connector type of this invention can all be adjusted according to the application scenario. Therefore, it can adapt to the usage requirements of different transmission bandwidths, laying lengths, working water depths, and external interference levels, and has strong versatility and promotional value. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the underwater high-frequency anti-interference cable of the present invention; Figure 2 for Figure 1 A schematic diagram of the underwater pluggable connector structure of a mid-water high-frequency anti-interference cable; Figure 3 for Figure 1 A schematic diagram of the connection of the treatment layer of the mid-water underwater high-frequency anti-interference cable.

[0026] Explanation of reference numerals in the attached figures: Core transmission layer 1, central conductor group 11, differential transmission line 111, power transmission line 12, control signal line 13.

[0027] Intermediate shielding and isolation layer 2, first shielding layer 21, first isolation layer 22, second shielding layer 23, second isolation layer 24.

[0028] Processing layer 3, signal processing module 31, module housing 311, signal input terminal 312, signal output terminal 313, circuit processing unit 314, frequency adaptive processing unit 3141, real-time spectrum analysis unit 3142, interference detection unit 3143, adaptive filtering unit 3144, active anti-interference circuit 3145, common mode choke 31451, current compensation generator 31452, EMI filter 31453.

[0029] Outer protective structure 4, inner sheath 41, reinforcing layer 42, outer sheath 43.

[0030] 5. Pressure balancing system; 51. Hydrophobic filling medium; 52. Pressure compensation structure.

[0031] The underwater pluggable connector structure includes: 6. Connector housing 61. Conductor connection end 62. Shielding connection end 63. Sealing component 64. Locking component 65.

[0032] Water-blocking strip 7. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0034] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0036] like Figures 1-3 As shown, this embodiment provides an underwater high-frequency anti-interference cable, including a core transmission layer 1, an intermediate shielding and isolation layer 2, a processing layer 3, and an outer protective structure 4.

[0037] The core transmission layer 1 is located in the central region of the cable and is used for transmitting electrical signals. The core transmission layer 1 includes a central conductor group 11, power transmission lines 12, and control signal lines 13. The central conductor group 11 includes four pairs of differential transmission lines 111, which are preferably twisted along the cable axis to improve common-mode interference immunity and impedance consistency. The power transmission lines 12 supply power to active modules in underwater equipment or cables, and the control signal lines 13 transmit low-speed control commands, status feedback information, or auxiliary synchronization signals.

[0038] In a preferred embodiment, the conductors of the differential transmission lines 111 are made of silver-plated annealed copper wire or other low-loss conductor materials suitable for high-frequency transmission. The insulation layer can be made of expanded polytetrafluoroethylene (PTFE), modified polyolefin, or other low-dielectric-constant insulating materials to reduce high-frequency transmission loss. The four pairs of differential transmission lines 111 can be stranded with different pitches to reduce crosstalk between pairs. The power transmission line 12 can be located around the center conductor group 11 or in the gap area, and the control signal line 13 can be arranged in the gap area between the differential transmission lines 111 or around the center conductor group 11 to balance structural compactness and interlayer isolation.

[0039] The intermediate shielding and isolation layer 2 covers the periphery of the core transmission layer 1 and is used to reduce external electromagnetic interference and internal signal crosstalk. The intermediate shielding and isolation layer 2 includes a first shielding layer 21, a first isolation layer 22, a second shielding layer 23, and a second isolation layer 24 arranged sequentially.

[0040] The first shielding layer 21 can be made of aluminum foil wrapping, metal composite tape wrapping, or woven metal mesh, preferably a composite structure of aluminum foil and polyester tape, to achieve primary shielding against high-frequency electromagnetic fields; the first isolation layer 22 can be formed by wrapping with polymer insulating material to electrically isolate the first shielding layer 21 from the second shielding layer 23; the second shielding layer 23 can be made of tin-plated copper wire braided layer, silver-plated copper braided layer, or metal tape wrapping to further enhance the overall shielding capability; the second isolation layer 24 is used to separate the outer sheath structure from the shielding structure to prevent the outer structure from causing wear or stress concentration on the shielding layer.

[0041] The processing layer 3 is spaced apart along the length of the cable. Specifically, the processing layer 3 includes multiple signal processing modules 31, each of which can be installed in a reserved section inside the cable and electrically connected to the high-frequency transmission channel in the central conductor group 11. The signal processing modules 31 are used to shape, compensate, filter, equalize, or perform anti-interference processing on the signals during transmission. The spacing between the signal processing modules 31 can be determined based on the transmission distance, target frequency band, marine interference environment, and allowable loss range. For example, in underwater deployment scenarios at depths of tens to hundreds of meters, they can be arranged in segments at preset distances to reduce the cumulative attenuation problem during centralized processing.

[0042] The outer protective structure 4 is disposed around the treatment layer 3 and the intermediate shielding and isolation layer 2, and includes an inner sheath 41, a reinforcing layer 42, and an outer sheath 43. The inner sheath 41 covers the outside of the intermediate shielding and isolation layer 2 to form a basic sealed enclosure. The reinforcing layer 42 is disposed around the inner sheath 41 and can be one or more of aramid fiber braided layers, high-strength polymer fiber layers, and metal wire reinforcing layers to improve the overall tensile strength and bending resistance of the cable. The outer sheath 43 is disposed around the reinforcing layer 42 and can be made of high-molecular materials that are resistant to seawater corrosion, wear, low temperature, and aging, such as polyurethane, chlorinated polyethylene, modified polyolefins, and thermoplastic elastomers. To improve weather resistance and underwater adaptability, anti-UV, anti-hydrolysis, antibacterial, or anti-biofouling additives can also be added to the outer sheath 43.

[0043] With the above structural design, the cable in this embodiment can simultaneously achieve stable transmission of multiple signal types in an underwater environment, while taking into account anti-interference capability, mechanical strength, and long-term environmental adaptability.

[0044] Based on the above embodiments, this embodiment further describes the pressure balancing system 5.

[0045] In underwater environments, especially deep water environments, the external hydrostatic pressure increases significantly with depth. If the cable's interior uses only a regular cavity or conventional solidified filling structure, it is prone to localized compression deformation due to the pressure difference between the inside and outside, which in turn affects the conductor arrangement, the shielding layer's adhesion, and the stability of the signal processing module 31. Therefore, this embodiment incorporates a pressure balancing system 5 inside the cable.

[0046] The pressure balancing system 5 includes a hydrophobic filling medium 51 and a pressure compensation structure 52.

[0047] The hydrophobic filling medium 51 can be filled between the central conductor groups 11, in the gaps of the intermediate layer, and around the mounting area of ​​the signal processing module 31 to reduce internal voids, prevent moisture from penetrating along the cable axis, and buffer pressure transmission to a certain extent. The hydrophobic filling medium 51 can be a silicone gel, hydrophobic grease, hydrophobic elastic filler material, or other filling medium with low water absorption and good environmental stability.

[0048] The pressure compensation structure 52 can be installed in a local section of the cable or in the transition area of ​​the joint to achieve internal pressure buffering and balance when the external pressure changes. Preferably, the pressure compensation structure 52 can take the form of an elastic compensation cavity, a flexible diaphragm structure, a variable volume cavity, or a miniature pressure balancing unit. Through this structure, when the external pressure increases, the compensation structure undergoes controlled deformation to reduce the degree of pressure concentration on the core transmission layer 1 and the signal processing module 31; when the external pressure decreases, the compensation structure can restore or rebalance its internal state, thereby reducing the fatigue effects caused by repeated pressure difference changes.

[0049] By setting up the pressure balancing system 5, the impact of deep-water pressure changes on the electrical performance and structural integrity of the cable can be effectively reduced, thereby improving long-term service stability.

[0050] Based on the above embodiments, this embodiment further illustrates the preferred structure of the processing layer 3.

[0051] The signal processing modules 31 are spaced apart along the length of the cable. Each signal processing module 31 includes a module housing 311, a signal input terminal 312, a signal output terminal 313, and a circuit processing unit 314. The circuit processing unit 314 includes a frequency adaptive processing unit 3141, a real-time spectrum analysis unit 3142, an interference detection unit 3143, an adaptive filtering unit 3144, and an active anti-interference circuit 3145.

[0052] The real-time spectrum analysis unit 3142 detects interference in the current transmission signal's frequency band and surrounding frequency bands to obtain information such as interference intensity, frequency distribution, and noise variation trends. The interference detection unit 3143 identifies the type of interference based on the detected spectrum information, such as broadband noise interference, narrowband interference, periodic pulse interference, or common-mode interference. The frequency adaptive processing unit 3141 adjusts the current operating frequency band, subcarrier distribution, equalization parameters, or compensation parameters based on the detection results. The adaptive filtering unit 3144 suppresses target interference frequency bands while maintaining signal quality within the effective transmission frequency band.

[0053] The active anti-interference circuit 3145 may include a common-mode choke 31451, a current compensation generator 31452, and an EMI filter 31453.

[0054] Among them, the common-mode choke 31451 is mainly used to suppress common-mode interference components in the line; the current compensation generator 31452 can generate compensation signals according to the detected interference characteristics to cancel out part of the interference; the EMI filter 31453 is used to filter out stray noise and high-frequency interference components that exceed the target operating frequency band.

[0055] In a preferred embodiment, the signal processing module 31 employs a sealed encapsulation structure, with an external waterproof insulating encapsulation layer covering it, forming a reliable fixed connection with the internal layer structure of the cable. Power to the module can be provided by the power transmission line 12, and control and status feedback signals can be transmitted via the control signal line 13. To prevent the module area from becoming a mechanical weak point in the cable, a stress buffer layer can be provided on the outer periphery of the module housing 311, forming a transitional encapsulation with the inner sheath 41.

[0056] With the above settings, the signal processing module 31 in this embodiment can not only perform segmented shaping and compensation of high-frequency signals, but also perform active anti-interference processing according to the real-time interference situation in the underwater environment, thereby improving the robustness of the high-frequency communication link.

[0057] Based on the above embodiments, this embodiment further describes the underwater pluggable connector structure 6 used in conjunction with the cable.

[0058] The underwater pluggable connector is located at the end of the cable and is used to achieve a detachable connection between the cable and the underwater equipment. The connector includes a connector housing 61, a conductor connection end 62, a shield connection end 63, a sealing component 64, and a locking component 65.

[0059] The conductor connection end 62 is respectively connected to the differential transmission line 111, the power transmission line 12, and the control signal line 13 in the central conductor group 11; the shielding connection end 63 is electrically connected to the first shielding layer 21 and / or the second shielding layer 23 to ensure the continuity of cable shielding. The sealing assembly 64 may include a main sealing ring, an auxiliary sealing ring, an end face sealing structure, and a potting sealing structure to prevent moisture from entering the cable from the joint interface. The locking assembly 65 may be a threaded locking structure, a snap-locking structure, or a rotary pressing structure to improve the stability of the underwater connection and prevent the plug from loosening.

[0060] Preferably, the connector housing 61 is made of corrosion-resistant metal material or high-strength engineering plastic, and an impedance matching structure can be set between the conductor connection end 62 and the modular circuit to reduce reflection loss and high-frequency mismatch in the connector area.

[0061] In the transition area where the joint connects to the cable body, stress relief sleeves, sealing transition sleeves, and reinforced crimping structures can be installed to avoid damage to the root of the joint caused by repeated bending or external pulling.

[0062] By setting the underwater pluggable connector structure 6, the cable of the present invention can maintain high-frequency transmission performance and waterproof sealing performance while having good assembly, disassembly and maintenance convenience.

[0063] In a preferred embodiment, all four pairs of differential transmission lines 111 are made of silver-plated annealed copper conductors and covered with a foamed PTFE insulation layer. The twist pitch of each pair is different to reduce electromagnetic coupling between adjacent pairs.

[0064] The first shielding layer 21 is formed by wrapping aluminum foil-polyester composite tape, and the second shielding layer 23 is formed by braiding tin-plated copper wire.

[0065] Both the first isolation layer 22 and the second isolation layer 24 are formed by wrapping with high-density insulating polymer tape.

[0066] The inner sheath 41 may be made of hydrolysis-resistant polyurethane material, the reinforcing layer 42 may be made of aramid fiber woven layer, and the outer sheath 43 may be made of wear-resistant and corrosion-resistant thermoplastic polyurethane material.

[0067] In another preferred embodiment, to further improve water-blocking capability, a water-blocking strip 7 can be provided between the intermediate shield and the isolation layer 2 or between the sheath layers. When the cable is locally damaged, the water-blocking strip 7 can slow down the axial diffusion of moisture, thereby reducing the risk of large-scale failure.

[0068] In another preferred embodiment, an anti-marine organism attachment additive may be added to the outer sheath 43 material to reduce the impact of barnacles, algae and other attachments on the cable's flexibility and surface integrity during long-term marine use.

[0069] When the underwater high-frequency anti-interference cable of the present invention is in use, the central conductor group 11 undertakes the task of high-frequency data signal transmission, the power transmission line 12 supplies power to the underwater terminal equipment and the signal processing module 31 inside the cable, and the control signal line 13 is used to transmit module control commands and status information.

[0070] During signal transmission, the intermediate shielding and isolation layer 2 first shields and suppresses external electromagnetic interference and internal coupling crosstalk; when the high-frequency signal is attenuated, distorted or interfered with during long-distance transmission, the signal processing module 31 set along the line detects, shapes, compensates and actively resists interference to maintain link quality.

[0071] Meanwhile, the outer protective structure 4 provides mechanical support and environmental protection for the entire cable, while the pressure balancing system 5 mitigates the adverse effects of deep-water pressure changes on the internal structure and electrical performance.

[0072] When the cable is connected to external equipment, the underwater pluggable connector structure 6 ensures conductor connection, shielding continuity and interface sealing, thereby forming a complete underwater high-frequency transmission system.

[0073] Corresponding to the aforementioned method, the present invention may also employ the following working mode: During cable operation, the signal processing module 31 performs a spectrum scan on the current transmission frequency band to identify frequency bands with high interference intensity. After identifying the target interference frequency band, the transmission parameters of the high-frequency signal are adjusted, such as switching sub-bands, adjusting transmission power, modulation method or coding rate, to avoid strong interference frequency points or reduce the risk of bit errors.

[0074] In a preferred embodiment, OFDM modulation and forward error correction mechanisms can also be used to improve communication fault tolerance in complex interference environments.

[0075] The above method can be implemented using the signal processing module 31 installed inside the cable, or it can be implemented in conjunction with the cable end equipment.

[0076] It should be noted that the present invention is not limited to the specific form of four pairs of differential transmission lines 111. In other embodiments, the number of pairs of differential transmission lines 111 can be set to two, six or more pairs according to bandwidth requirements; the number of power transmission lines 12 and control signal lines 13 can also be adjusted according to the interface requirements of underwater equipment.

[0077] The signal processing module 31 can be deployed at fixed intervals or at non-equal intervals based on the distribution of interference intensity, changes in laying length, or the location of underwater equipment nodes.

[0078] The shielding layer can be made by a combination of wrapping and braiding, or by a multi-layer metal composite membrane structure; the pressure compensation structure 52 can also be made by other equivalent structures that can achieve internal and external pressure difference buffering.

[0079] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. An underwater high-frequency anti-interference cable, characterized in that, From the inside out, it includes: The core transmission layer includes a central conductor group, power transmission lines and control signal lines. The central conductor group includes four pairs of differential transmission lines. Each pair of differential transmission lines includes an inner conductor, an insulating layer covering the outside of the inner conductor, and an outer conductor disposed outside the insulating layer. Each pair of differential transmission lines is twisted together at a preset pitch. An intermediate shielding and isolation layer, comprising a first shielding layer, a first isolation layer, a second shielding layer, and a second isolation layer sequentially disposed outside the core transmission layer; The processing layer includes a plurality of signal processing modules spaced apart along the length of the cable and an active anti-interference circuit electrically connected to the signal processing modules. The signal processing modules are used to perform spectrum analysis and interference detection on the high-frequency signals transmitted by the center conductor group, and the active anti-interference circuit is used to suppress the detected interference signals. An outer protective structure, comprising an inner sheath, a reinforcing layer, and an outer sheath, wherein the outer side of the outer sheath is for contact with the underwater environment; And a pressure balancing system, the pressure balancing system including a hydrophobic filling medium disposed inside the cable and a pressure compensation structure disposed at the cable joint; The signal processing module is used to adaptively process the transmitted signal in the 50MHz~1GHz frequency band to improve the underwater high-frequency signal transmission capability and anti-interference performance.

2. The underwater high-frequency anti-interference cable according to claim 1, characterized in that, The inner conductor is silver-plated annealed copper wire, the outer conductor is tin-plated copper braided layer, the insulation layer is foamed polytetrafluoroethylene layer, and the twist pitch of the differential transmission line is 15~25mm.

3. The underwater high-frequency anti-interference cable according to claim 1, characterized in that, The first shielding layer is an aluminum foil wrapping layer, the first isolation layer is a polyester tape wrapping layer, the second shielding layer is a tin-plated copper wire braided layer, and the second isolation layer is a water-blocking tape layer.

4. The underwater high-frequency anti-interference cable according to claim 1, characterized in that, The signal processing module includes a frequency adaptive processing unit, a real-time spectrum analysis unit, an interference detection unit, and an adaptive filtering unit. The frequency adaptive processing unit is used to select the operating sub-frequency band with the highest signal-to-noise ratio based on the spectrum analysis results, and the adaptive filtering unit is used to adjust the filtering parameters based on the interference detection results. The signal processing module is installed every 50 meters along the length of the cable and is connected to the core transmission layer via a flexible printed circuit board.

5. The underwater high-frequency anti-interference cable according to claim 1, characterized in that, The active anti-interference circuit includes a common-mode choke, a current compensation generator, and an EMI filter. The common-mode choke is used to suppress common-mode interference, the current compensation generator is used to inject reverse compensation current, and the EMI filter is used to filter out electromagnetic interference signals within a preset frequency band.

6. The underwater high-frequency anti-interference cable according to claim 1, characterized in that, The inner sheath is a modified polyurethane layer, the reinforcing layer is an aramid fiber braided layer, and the outer sheath is a polyamide-polyurethane composite elastomer layer. The outer sheath contains at least two of the following: anti-biofouling additives, anti-hydrolysis stabilizers, and anti-ultraviolet absorbers.

7. The underwater high-frequency anti-interference cable according to claim 1, characterized in that, The hydrophobic filling medium is silicone grease, and the pressure compensation structure is a pressure compensation membrane installed at the cable joint to balance the internal and external water pressure of the cable.

8. The underwater high-frequency anti-interference cable according to claim 1, characterized in that, It also includes an underwater pluggable connector, which includes a sealing structure, an electrical connection structure, and a smart interface. The sealing structure includes a primary seal and a secondary seal. The electrical connection structure includes impedance matching contacts. The smart interface includes a microcontroller for storing cable parameters and historical data. The main sealing element is an O-ring, the secondary sealing element is a potting resin layer, the impedance matching contact is a gold-plated contact, and the characteristic impedance of the underwater pluggable connector in the 50MHz~1GHz frequency band is 50Ω±2%.

9. A method for underwater high-frequency anti-interference transmission based on the underwater high-frequency anti-interference cable according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. The signal processing module performs a spectrum scan on the 50MHz-1GHz operating frequency band; the period of the spectrum scan is any preset period from 100ms to 5min, which is set according to the channel stability of the current application scenario. S2. Identify the frequency bands and intensity of interference sources based on the spectrum scanning results; S3. Select at least one sub-frequency band with the highest signal-to-noise ratio from the operating frequency band as the current transmission frequency band; S4. Adaptively adjust the transmit power, modulation scheme, and coding rate according to the selected transmission frequency band; the modulation scheme is one of QPSK, 16QAM, or 64QAM, and the coding rate is one of 1 / 2, 2 / 3, 3 / 4, or 5 / 6. S5. During signal transmission, the active anti-interference circuit suppresses common-mode interference and electromagnetic interference; forward error correction coding and interleaving coding are performed on the transmitted signal, and channel estimation is performed based on pilot symbols to reduce the bit error rate and improve the stability of underwater high-frequency transmission. S6. During the transmission process, steps S1 to S5 are periodically repeated to dynamically adjust the high-frequency transmission parameters.

10. The underwater high-frequency anti-interference transmission method according to claim 9, characterized in that, The signal transmission adopts OFDM transmission mode, with 256 subcarriers and a subcarrier spacing of 15.625kHz, and a cyclic prefix is ​​set to reduce the impact of multipath interference.

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