Method for using a broadband underwater transducer in one-way acoustic communication

Abstract

The application relates to a method for applying a broadband underwater transducer in one-way acoustic communication and belongs to the technical field of one-way underwater acoustic communication without backhaul. The method comprises the following steps: S1, underwater frequency sweeping of a multimodal phase control broadband underwater transducer is carried out at a transmitting end to obtain an amplitude-frequency response, a phase-frequency response and an electric impedance response; S2, available communication subbands are divided according to the response curves; and S3, an application configuration file for low-speed control instructions and medium-high-speed data is established. The low-speed control instructions and the medium-high-speed data are respectively mapped to the communication subbands matched with actual transducer responses, configuration sharing of the transmitting end and a receiving end is completed before deployment, local parameter updating is completed before a task or during a task interval, the same broadband transducer can be reused in different communication tasks, and the influence of modal response, impedance change and platform working condition change on communication quality is reduced.

Description

Technical Field

[0001] This invention relates to a method for applying a broadband underwater transducer in unidirectional acoustic communication, belonging to the field of non-returning unidirectional underwater acoustic communication technology. Background Technology

[0002] Underwater acoustic communication typically converts modulated electrical signals into underwater acoustic signals using a transmitting transducer. Compared to electromagnetic wave communication, underwater acoustic signals are suitable for long-distance information transmission in seawater, but are affected by propagation loss, reverberation, multipath propagation, frequency selectivity, and platform noise. Communication transmitters need to improve the utilization of available frequency bands within limited power, bandwidth, and deployment space.

[0003] The "Deep Blue Heart" project presents a technical roadmap for low-frequency broadband underwater loudspeakers that combines piezoelectric ceramic actuation, multimodal coupling, and bending / tensioning radiation structures. The paper further investigates modal phase difference, center-driven bending transducers, and broadband Type IV bending transducers, and presents underwater test results for prototypes. While these technologies provide a broadband sound source carrier for underwater communication, the amplitude, phase, and impedance responses of the transducers cannot be directly equated to the communication channel response; therefore, an application-oriented transmission parameter management process is needed.

[0004] Defects and shortcomings of existing technology: 1. Existing communication transmitters often use fixed carriers or fixed equalization parameters, and do not establish callable communication configuration files based on the underwater measured amplitude frequency, phase frequency and impedance response of each broadband transducer.

[0005] 2. Different modes of a multimode transducer may cause local frequency response dips, phase abrupt changes, and group delay differences; directly loading the communication waveform can lead to inconsistent sound pressure levels in each subband, waveform distortion, inter-symbol interference, or a decrease in effective bandwidth.

[0006] 3. A single matching network state cannot take into account the power transmission and safety boundaries of multiple modal ranges, which may result in unreasonable drive voltage, current or power utilization in certain frequency bands.

[0007] 4. When the towed platform sends control commands or data to the underwater node, the mission link may only need to send in one direction; if parameter adjustments are based on real-time feedback, it will increase the complexity of deployment, power supply and communication protocols.

[0008] Current technologies for deploying broadband underwater transducers in practical underwater acoustic communication typically discuss the acoustic performance of the transducer, the modulation and demodulation parameters of the communication device, and the driving parameters of the power amplifier separately, lacking an application process that unifies these three aspects with the specific deployment task. Especially in scenarios where towed platforms transmit information unidirectionally to underwater nodes, the transmitter cannot or does not need to rely on real-time feedback to repeatedly adjust parameters; if a fixed carrier, fixed equalization, and fixed matching state are still used, it is difficult to adapt to the actual response under different transducers, different installation attitudes, different water depths, and different mission frequency bands.

[0009] Therefore, there is an urgent need to propose a method for applying broadband underwater transducers in unidirectional acoustic communication to solve the above-mentioned technical problems. Summary of the Invention

[0010] To solve the technical problem: 1. How to obtain the amplitude frequency response, phase frequency response, group delay and impedance response under actual installation conditions through underwater frequency sweep and electrical parameter measurement before the transducer is put into communication mission, and convert the above responses into an application configuration file that can be called by both the transmitter and receiver, so as to avoid selecting the communication frequency band based solely on theoretical design curves or factory nominal parameters.

[0011] 2. How to identify available communication subbands that meet the requirements of sound pressure, signal-to-noise ratio, phase continuity and drive safety boundaries for multimodal transducers that may have response dips, amplitude fluctuations, phase abrupt changes and group delay differences in different modal ranges, and how to configure communication resources suitable for low-speed control commands and medium-to-high-speed data on the same transducer respectively.

[0012] 3. How to generate amplitude pre-emphasis, phase pre-compensation, and group delay pre-compensation parameters based on the measured response of each available communication sub-band, so that the control information or data symbols carried by different sub-bands have controllable sound pressure, phase, and time relationships at the output of the underwater transducer, thereby reducing waveform distortion, inter-symbol interference, and effective bandwidth loss.

[0013] 4. How to correlate the impedance variation of the transducer, the matching network branch, the output range of the power amplifier, and the usage status of each communication subband to achieve broadband drive under the conditions of meeting voltage, current, power, and transducer safety limits, and avoid overdrive in a certain mode range or power utilization reduction caused by conservative limiting.

[0014] 5. How to enable the underwater receiving node to obtain the same synchronization, demodulation, and error correction parameters as the transmitter before deployment without setting up a real-time backhaul link, and allow the transmitter to update the next mission configuration based on sensor measurements before the mission starts or during mission intervals, thereby adapting to changes in the towed platform's track, attitude, depth, and surrounding noise.

[0015] 6. How to make the above application process independent of a specific transducer shape, and adaptable to center-driven bending type, IV-type bending type and other broadband underwater transducers with multiple available modal ranges, while maintaining the correspondence between communication configuration, compensation parameters and matching drive.

[0016] This invention provides a method for applying a broadband underwater transducer in unidirectional acoustic communication. A brief overview of the invention is given below to provide a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0017] The technical solution of the present invention: A method for applying a broadband underwater transducer in unidirectional acoustic communication includes the following steps: S1. At the transmitting end, perform underwater frequency sweeping on the multi-mode phase-controlled broadband underwater transducer to obtain the amplitude frequency response, phase frequency response and electrical impedance response; S2. Divide the available communication subbands according to the response curve; S3. Establish application configuration files for low-speed control commands and medium-to-high-speed data.

[0018] Preferably, in S1, a broadband underwater transducer is installed on a towed platform or test support, and a reference hydrophone is set at a reference distance; a sweep frequency signal is applied to the transducer, and the sound pressure level, amplitude frequency response, phase frequency response, voltage and current at each frequency are recorded to obtain the impedance response.

[0019] Preferably, in S2, at least two usable communication sub-bands are determined based on the peak, dip and fluctuation of the amplitude frequency response, combined with the change in phase frequency response, group delay and communication signal-to-noise ratio; the intervals where the response is below the threshold, the phase change is too fast or the safety power margin is insufficient are set as avoidance intervals.

[0020] Preferred: S3 includes the following steps: S31. Application configuration file creation; S32, Generation of compensation and matching parameters; S33, One-way transmission; S34. Update before or during the break between tasks.

[0021] Preferably, in S31, configuration files are established for control commands and medium-to-high-speed data respectively; the control command configuration file preferentially selects subbands with higher signal-to-noise ratio margin and lower symbol rate; the data configuration file selects multiple available subbands and configures higher effective bandwidth; each configuration file corresponds in advance to the demodulation, synchronization and error correction parameters of the receiver.

[0022] Preferred configuration: In S32, an amplitude pre-emphasis coefficient is generated based on the difference between the measured sound pressure response and the target response of each sub-band; a phase / group delay compensation amount is generated based on the phase frequency response slope or pilot arrival time; a series or parallel matching branch, damping resistor, transformer ratio or branch selection status is generated based on the impedance response and bound to the configuration file; and the maximum amplitude limit value is set for all compensation and drive parameters.

[0023] Preferred configuration: In S33, after the control command or data to be sent is framed, encoded and modulated, the corresponding configuration file is called according to the message type to perform subband mapping, amplitude pre-emphasis and phase / group delay pre-compensation; the matching parameters are called according to the subband occupied by the current frame, and the transducer is driven by the power amplifier and the matching network to be sent unidirectionally from the towed platform to the underwater node.

[0024] Preferably, in S34, before the start of a mission or during a mission interval, the transmitter uses at least one of a reference hydrophone, a voltage sensor, and a current sensor to update the configuration file to be used in the next mission; if the update involves demodulation parameters of the receiver, the configuration file is shared with the receiver again before the next mission, and real-time feedback is not relied upon during communication.

[0025] Preferably, an adaptive broadband underwater acoustic transducer based on modal phase feedback is used, comprising: the output side of the transducer body, a signal acquisition module, a modal analysis module, a phase feedback module, an intelligent decision-making module, and a parameter adjustment module connected in sequence, and the input side of the transducer body is connected to a drive power amplifier; The drive power amplifier is used to provide drive signals to the transducer body; The signal acquisition module is used to acquire voltage signals, current signals, and impedance signals during the operation of the transducer; The modal analysis module is used to perform frequency domain analysis on the acquired signals and extract modal feature parameters; The phase feedback module is used to calculate the phase difference between adjacent modes and generate feedback information; The intelligent decision-making module is used to generate control strategies based on modal state information; The parameter adjustment module is used to adjust the driving frequency, driving phase, driving voltage, and matching network parameters.

[0026] The present invention has the following beneficial effects: 1. By performing underwater response scanning on each transducer and establishing an application configuration file, the actual acoustic characteristics of the transducer are converted into parameters that can be directly called by the communication system, reducing the error caused by the mismatch between fixed equalization parameters and the actual sound source.

[0027] 2. By identifying available sub-bands, setting avoidance intervals, and compensating for amplitude / phase / group delay, the impact of multimodal response dips and modal phase differences on the reliable arrival of control commands and the effective bandwidth of medium- and high-speed data is reduced.

[0028] 3. By binding matching parameters to application configuration files, different subbands can operate under corresponding impedance transformation and power amplifier limiting conditions, thereby improving the power utilization and safety of broadband drives.

[0029] 4. By sharing configuration files before deployment and updating locally before / during task intervals, communication tasks do not rely on backhaul links during execution, making it suitable for rapid deployment on drag-and-drop platforms, low power consumption, and one-way broadcasting.

[0030] 5. The same application process is compatible with broadband transducers such as center-driven bending type and IV-type bending tension type, which facilitates selection based on towed platform load, water depth, mission frequency band and receiver node type. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the system structure of an adaptive broadband underwater acoustic transducer based on modal phase feedback according to the present invention. Figure 2 This is a flowchart of an adaptive broadband underwater acoustic transducer control method based on modal phase feedback according to the present invention. Figure 3 This is a flowchart of the modal analysis and phase feedback process of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0033] Specific implementation method one: Combining Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in unidirectional acoustic communication, comprising the following steps: S1. At the transmitting end, perform underwater frequency sweeping on the multi-mode phase-controlled broadband underwater transducer to obtain the amplitude frequency response, phase frequency response and electrical impedance response; S2. Divide the available communication subbands according to the response curve; S3. Establish application configuration files for low-speed control commands and medium-to-high-speed data; Each configuration file must include at least the message type, subband enable status, modulation / coding parameters, amplitude compensation coefficient, group delay compensation amount, and matching parameters; the transmitter and receiver share the configuration file before deployment, and the receiver is not required to send control information back to the transmitter during the execution of the communication task; This invention provides a non-returning unidirectional underwater acoustic communication method, starting with transducer underwater response calibration, using application configuration file management as a link, and incorporating available subband scheduling, amplitude / phase / group delay compensation, and matching drive as its core. This invention maps low-speed control commands and medium-to-high-speed data to communication subbands that match the actual transducer response. Configuration sharing between the transmitter and receiver is completed before deployment, and local parameter updates are performed before or during mission intervals. This allows the same broadband transducer to be reused in different communication missions, reducing the impact of modal response, impedance variations, and platform operating condition changes on communication quality.

[0034] Specific Implementation Method Two: Combining Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in unidirectional acoustic communication. In the underwater response scan (S1), the broadband underwater transducer is installed on a towed platform or test support, and a reference hydrophone is set at a reference distance. A sweep frequency signal is applied to the transducer, and the sound pressure level, amplitude frequency response, phase frequency response, and voltage and current across the transducer at each frequency are recorded to obtain the impedance response. 100 Hz to 20 kHz is the target range for the product; the specific implementation frequency band is determined by the actual prototype and test conditions.

[0035] Specific implementation method three: Combining Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in unidirectional acoustic communication. In S2, when identifying available subbands, at least two available communication subbands are determined based on the peak, dip, and fluctuation of the amplitude frequency response, combined with the change in phase frequency response, group delay, and communication signal-to-noise ratio. The intervals where the response is below the threshold, the phase change is too fast, or the safety power margin is insufficient are set as avoidance intervals.

[0036] Specific implementation method four: Combination Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in unidirectional acoustic communication. S3 includes the following steps: S31. Application configuration file creation; S32, Generation of compensation and matching parameters; S33, One-way transmission; S34. Update before or during the break between tasks.

[0037] Specific Implementation Method Five: Combining Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in unidirectional acoustic communication. In step S31, configuration files are established for control commands and medium-to-high-speed data. The control command configuration file preferentially selects subbands with higher signal-to-noise ratio margin and lower symbol rate. The data configuration file selects multiple available subbands and configures them with higher effective bandwidth. Each configuration file corresponds in advance to the demodulation, synchronization, and error correction parameters of the receiving end.

[0038] Specific Implementation Method Six: Combination Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in unidirectional acoustic communication. In step S32, an amplitude pre-emphasis coefficient is generated based on the difference between the measured sound pressure response of each sub-band and the target response; a phase / group delay compensation amount is generated based on the phase frequency response slope or pilot arrival time; a series or parallel matching branch, damping resistor, transformer ratio, or branch selection status is generated based on the impedance response and bound to the configuration file; and the maximum amplitude limit is set for all compensation and drive parameters.

[0039] Specific implementation method seven: Combination Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in unidirectional acoustic communication. In step S33, after the control command or data to be transmitted is framed, encoded, and modulated, the corresponding configuration file is called according to the message type to perform subband mapping, amplitude pre-emphasis, and phase / group delay pre-compensation. Matching parameters are called according to the subband occupied by the current frame, and the transducer is driven by the power amplifier and matching network to be unidirectionally transmitted from the towed platform to the underwater node.

[0040] Specific implementation method eight: Combination Figure 1-3 This embodiment describes a method for applying a broadband underwater transducer in one-way acoustic communication. In S34, before the start of a mission or during a mission interval, the transmitter uses at least one of a reference hydrophone, a voltage sensor, and a current sensor to update the configuration file to be used in the next mission. If the update involves demodulation parameters of the receiver, the configuration file is shared with the receiver again before the next mission, and real-time transmission is not relied upon during communication. Key parameter relationships: Parameter Category: Specific Content and Function Message type: Low-speed control command or wake-up signal; medium-to-high-speed data or status information; Sound source response: amplitude frequency response, phase frequency response, group delay, impedance, drive voltage / current and power limit; Communication parameters: can include sub-band, modulation / coding parameters, amplitude compensation coefficient, phase or group delay compensation amount; Drive parameters: matching network branches, series and parallel components, transformer turns ratio, power amplifier output limiting; Sharing relationship: The configuration file is shared by the transmitter and receiver before deployment, and only one-way acoustic transmission is performed during task execution.

[0041] Specific Implementation Method Nine: Combining Figure 1-3This embodiment describes an application method of a broadband underwater transducer in unidirectional acoustic communication. It employs an adaptive broadband underwater acoustic transducer based on modal phase feedback, comprising: a transducer body 1, a signal acquisition module 2, a modal analysis module 3, a phase feedback module 4, an intelligent decision-making module 5, a parameter adjustment module 6, and a drive power amplifier 7. The output side of the transducer body 1, the signal acquisition module 2, the modal analysis module 3, the phase feedback module 4, the intelligent decision-making module 5, and the parameter adjustment module 6 are connected sequentially, and the input side of the transducer body 1 is connected to the drive power amplifier 7. The drive power amplifier 7 is connected to the transducer body 1 and is used to provide drive signals to the transducer body 1. The signal acquisition module 2 is connected to the transducer body 1 and is used to acquire voltage signals, current signals and impedance signals during the operation of the transducer. Modal analysis module 3 is connected to signal acquisition module 2 and is used to perform frequency domain analysis on the acquired signal and extract modal feature parameters; Phase feedback module 4 is connected to modal analysis module 3 and is used to calculate the phase difference between adjacent modes and generate feedback information. The intelligent decision-making module 5 is connected to the phase feedback module 4 and the historical database 8 respectively, and is used to generate control strategies based on modal state information. The intelligent decision-making module 5 can call the machine learning model 9, and after making a decision, it inputs the data into the model for calculation. The model outputs the prediction and evaluation results and sends them back to the intelligent decision-making module. The parameter adjustment module 6 is connected to the intelligent decision module 5 and is used to adjust the driving frequency, driving phase, driving voltage and matching network 10 parameters. Broadband underwater transducers can be center-driven bending transducers or Type IV bending-tension transducers, or other low-frequency broadband transducers with multiple available modal ranges. Structural features are used to provide broadband acoustic source response, and the core application of the independent claims is a combined process of "response calibration—configuration profile—subband scheduling—amplitude / phase / group delay compensation—matching drive—unidirectional transmission".

[0042] Example 1: See Figure 1 This embodiment provides an adaptive broadband underwater acoustic transducer based on modal phase feedback, including a transducer body 1, a signal acquisition module 2, a modal analysis module 3, a phase feedback module 4, an intelligent decision-making module 5, a parameter adjustment module 6, and a drive power amplifier 7.

[0043] A drive power amplifier 7 is connected to the transducer body 1 to provide drive signals to the transducer body 1. A signal acquisition module 2 is connected to the transducer body 1 to acquire voltage, current, and impedance signals during transducer operation. A modal analysis module 3 is connected to the signal acquisition module 2 to perform frequency domain analysis on the acquired signals and extract modal characteristic parameters. A phase feedback module 4 is connected to the modal analysis module 3 to calculate the phase difference between adjacent modes and generate feedback information. An intelligent decision-making module 5 is connected to both the phase feedback module 4 and the historical database 8 to generate control strategies based on modal state information. A parameter adjustment module 6 is connected to the intelligent decision-making module 5 to adjust the drive frequency, drive phase, drive voltage, and matching network 9 parameters. The transducer body 1 includes a piezoelectric drive assembly, an elastic vibrator, a radiating head, a tail mass, a pre-tightening mechanism, and a sealed shell. The piezoelectric drive assembly adopts a piezoelectric ceramic stack structure, a piezoelectric ring structure, or a piezoelectric composite material structure. The elastic vibrator is used to form multiple vibration modes and achieve broadband sound radiation. The radiating head radiates mechanical vibration energy into the water medium as acoustic energy. The tail mass is used to adjust the longitudinal vibration characteristics of the transducer. The preload mechanism provides preload force for the piezoelectric drive assembly. The sealing housing provides underwater sealing protection for the transducer.

[0044] See Figure 2 This embodiment provides an adaptive control method based on modal phase feedback, including the following steps: ① The transducer starts working and completes system initialization; ② Signal acquisition module 2 acquires voltage signals, current signals, and impedance signals in real time during the operation of the transducer; ③ Modal analysis module 3 performs spectral analysis on the acquired signals and identifies the vibration modes of the transducer; ④ Extract the frequency and phase features corresponding to each mode; ⑤ Phase feedback module 4 calculates the phase difference between adjacent modes; ⑥ Determine whether the phase difference is within the preset threshold range; ⑦ If the phase difference is within the threshold range, then maintain the current working state; ⑧ If the phase difference exceeds the threshold range, the intelligent decision module 5 generates a control command; ⑨ The parameter adjustment module 6 adjusts the drive frequency, drive phase, drive voltage, and matching network parameters according to the control commands; ⑩ Drive the power amplifier 7 to drive the transducer according to the adjusted parameters; Collect transducer operating status information again; Recalculate the modal characteristic parameters; Determine whether the current modal state has reached the target state; If the target state is reached, maintain the current operating parameters; If the target state is not achieved, return to step ⑧ to continue optimization; The system runs in a loop until the transducer stops working.

[0045] See Figure 3 The modal analysis process in step ③ is as follows: I. Acquire voltage, current, and impedance signals from the signal acquisition module; II. Perform filtering and noise suppression processing on the acquired signals; III. Use Fast Fourier Transform to perform frequency domain conversion on the time domain signal; IV. Obtain the transducer impedance-frequency response curve; V. Identify resonance peaks and anti-resonance peaks in impedance curves; VI. Determine the center frequency corresponding to each vibration mode; VII. Extract the frequency and phase features corresponding to each mode.

[0046] The Fast Fourier Transform analysis in step III uses a fixed time window or a sliding time window for frequency domain transformation.

[0047] The resonance peak in step V corresponds to the impedance minimum point, and the anti-resonance peak corresponds to the impedance maximum point.

[0048] The center frequency in step VI is the characteristic frequency corresponding to the adjacent resonance peak and the anti-resonance peak.

[0049] The frequency characteristics in step VII include the first mode frequency, the second mode frequency, and the third mode frequency.

[0050] The phase features in step VII include the first mode phase, the second mode phase, and the third mode phase.

[0051] The method for calculating the phase difference in step ⑤ is as follows: Δφ=φi-φi+1 in: φi represents the phase of the i-th mode; φi+1 represents the phase of the (i+1)th mode; Δφ represents the phase difference between adjacent modes.

[0052] The intelligent decision-making module in step ⑧ uses a machine learning model to generate control commands.

[0053] The input parameters of the machine learning model include: I. Modal frequencies; II. Modal phase difference; III. Impedance characteristic parameters; IV. Ambient temperature parameters; V. Environmental pressure parameters; VI. Historical operating status parameters.

[0054] The output parameters of the machine learning model include: I. Driving frequency adjustment amount; II. Driving phase adjustment amount; III. Driving voltage adjustment amount; IV. Match network adjustment parameters.

[0055] The matching network adjustment parameters in step 9 include adjustable capacitor parameters, adjustable inductor parameters, and impedance matching parameters.

[0056] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for applying a broadband underwater transducer in unidirectional acoustic communication, characterized in that: Includes the following steps: S1. At the transmitting end, perform underwater frequency sweeping on the multi-mode phase-controlled broadband underwater transducer to obtain the amplitude frequency response, phase frequency response and electrical impedance response; S2. Divide the available communication subbands according to the response curve; S3. Establish application configuration files for low-speed control commands and medium-to-high-speed data.

2. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 1, characterized in that: In S1, a broadband underwater transducer is installed on a towed platform or test support, and a reference hydrophone is set at a reference distance. A sweep frequency signal is applied to the transducer, and the sound pressure level, amplitude frequency response, phase frequency response, voltage and current at each frequency are recorded to obtain the impedance response.

3. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 2, characterized in that: In S2, at least two usable communication sub-bands are determined based on the peak, dip and fluctuation of the amplitude frequency response, combined with the phase frequency response change, group delay and communication signal-to-noise ratio; the intervals with responses below the threshold, phase changes too fast or insufficient safety power margin are set as avoidance intervals.

4. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 3, characterized in that: S3 includes the following steps: S31. Application configuration file creation; S32, Generation of compensation and matching parameters; S33, One-way transmission; S34. Update before or during the break between tasks.

5. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 4, characterized in that: In S31, configuration files are created for control commands and medium-to-high-speed data respectively; the control command configuration file prioritizes subbands with higher signal-to-noise ratio margin and lower symbol rate; the data configuration file selects multiple available subbands and configures higher effective bandwidth; each configuration file corresponds in advance to the demodulation, synchronization and error correction parameters of the receiver.

6. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 5, characterized in that: In S32, an amplitude pre-emphasis coefficient is generated based on the difference between the measured sound pressure response and the target response of each sub-band; a phase / group delay compensation amount is generated based on the phase frequency response slope or pilot arrival time; a series or parallel matching branch, damping resistor, transformer ratio or branch selection status is generated based on the impedance response and bound to the configuration file; and the maximum amplitude limit value is set for all compensation and drive parameters.

7. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 6, characterized in that: In S33, after the control commands or data to be sent are framed, encoded and modulated, the corresponding configuration file is called according to the message type to perform subband mapping, amplitude pre-emphasis and phase / group delay pre-compensation; according to the subband occupied by the current frame, the matching parameters are called, and the transducer is driven by the power amplifier and the matching network to send the data unidirectionally from the towed platform to the underwater node.

8. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 7, characterized in that: In S34, before the start of a mission or during a mission interval, the transmitter uses at least one of a reference hydrophone, a voltage sensor, and a current sensor to update the configuration file to be used in the next mission; if the update involves demodulation parameters of the receiver, the configuration file is shared with the receiver again before the next mission, and real-time transmission is not relied upon during communication.

9. The application method of a broadband underwater transducer in unidirectional acoustic communication according to claim 8, characterized in that: An adaptive broadband underwater acoustic transducer based on modal phase feedback is adopted, comprising: the output side of the transducer body (1), a signal acquisition module (2), a modal analysis module (3), a phase feedback module (4), an intelligent decision module (5), and a parameter adjustment module (6) connected in sequence, and the input side of the transducer body (1) is connected to the driving power amplifier (7). The drive power amplifier (7) is used to provide drive signals to the transducer body (1); The signal acquisition module (2) is used to acquire voltage signals, current signals and impedance signals during the operation of the transducer; The modal analysis module (3) is used to perform frequency domain analysis on the acquired signals and extract modal feature parameters; The phase feedback module (4) is used to calculate the phase difference between adjacent modes and generate feedback information; The intelligent decision-making module (5) is used to generate control strategies based on modal state information; The parameter adjustment module (6) is used to adjust the driving frequency, driving phase, driving voltage and matching network (10) parameters.

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