Low-noise audio acquisition circuit based on underwater glider

Abstract

The invention discloses a low-noise audio acquisition circuit based on an underwater glider. The low-noise audio acquisition circuit comprises a controller module used for controlling all modules and data transmission; the data storage module is used for storing effective data transmitted by the controller module and the processor module; the data interaction module is used for collecting state information of the underwater glider and sending the state information to the data storage module; the data processing module comprises an operational amplifier, a gain amplifier, a fully differential amplifier and a hydrophone for collecting audio information; audio information collected by the hydrophone is firstly subjected to preliminary amplification and impedance matching through the operational amplifier, then enters the gain amplifier to be subjected to flexible gain adjustment and signal optimization, is further amplified through the fully differential amplifier and inhibits common-mode interference, and finally, the audio information is transmitted to the analog-to-digital converter to complete analog-to-digital conversion. The processor module processes the received audio information and transmits the processed audio information to the data storage module.

Description

Technical Field

[0001] The present invention relates to the field of ocean acoustics, and in particular to a low-noise audio acquisition technology based on an underwater glider, and specifically to a low-noise audio acquisition circuit based on an underwater glider. Background Art

[0002] As an autonomous vehicle driven by buoyancy, underwater gliders have become an important carrier for deep-sea environmental monitoring due to their low energy consumption and long endurance. By integrating highly sensitive sensors, they can simultaneously obtain underwater acoustic signals during gliding, realizing real-time detection of marine biological activities, underwater targets and environmental noise.

[0003] The circuit design used in existing underwater gliders is as follows: the underwater acoustic detection hardware processing system includes signal acquisition, transmission, processing, storage, and interaction units. The system uses an MCU and a DSP to work together. The MCU uses an STM32 or FPGA chip, and a power management unit provides unified power to all modules. However, based on the circuit design and experimental data collection results, it can be seen that the data collected by this circuit is subject to periodic and non-periodic interference, which seriously affects the data quality.

[0004] The existing technology suffers from noise interference when integrating multiple sensors in conventional underwater glider acoustic acquisition systems. Weak currents and ambient noise can reduce the quality of high-precision underwater audio acquisition. Conventional circuit designs also have significant limitations in addressing noise interference: the audio acquisition module's noise suppression capabilities are insufficient. This is particularly true in complex ocean environments, where background noise overlaps with the target sonar signal's frequency band, making it difficult to effectively extract valid audio information and reducing the data signal-to-noise ratio. This present invention addresses the noise interference issue in conventional underwater glider acoustic acquisition systems by proposing an underwater audio acquisition circuit that significantly suppresses noise interference. Summary of the Invention

[0005] In view of the above-mentioned defects in the prior art, the present invention provides a low-noise audio acquisition circuit based on an underwater glider to improve the anti-interference capability of the audio acquisition system.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A low-noise audio acquisition circuit based on an underwater glider, comprising: a data interaction module, a data storage module, a processor module, a data processing module and a controller module;

[0008] The controller module is used to control each module and data transmission; the data storage module is used to store valid data transmitted by the controller module and the processor module;

[0009] The data interaction module is used to collect status information of the underwater glider and send the status information to the data storage module;

[0010] The data processing module includes an operational amplifier, a gain amplifier, a fully differential amplifier, and a hydrophone for collecting audio information;

[0011] The audio information collected by the hydrophone is firstly amplified and impedance matched by the operational amplifier, then enters the gain amplifier for flexible gain adjustment and signal optimization, and then further amplifies the signal and suppresses common-mode interference by the fully differential amplifier, and finally transmits the audio information to the analog-to-digital converter for analog-to-digital conversion;

[0012] The processor module processes the received audio information and transmits the processed audio information to the data storage module.

[0013] Preferably, the data processing module is powered and controlled by an independent analog power supply.

[0014] Preferably, the data storage module is connected to a USB connector, and a user can view the storage content of the SD card in the data storage module through the USB connector.

[0015] Preferably, the data interaction module includes a host computer system for debugging and controlling the circuit, a digital sensor for collecting information such as temperature, salinity, depth, etc., and an underwater glider main control circuit system.

[0016] Preferably, the controller module obtains external data through the data interaction module; the external data includes information transmitted by the underwater glider main control circuit system, information transmitted by the host computer system and information collected by sensors.

[0017] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0018] Different from the circuit design scheme adopted by existing underwater gliders, the low-noise audio acquisition circuit provided by the present invention uses a new data processing circuit. The weak differential signal collected by the hydrophone is first amplified and impedance-matched by an operational amplifier, and then enters the gain amplifier for flexible gain adjustment and signal optimization. The signal is then further amplified and common-mode interference is suppressed by a fully differential amplifier. Finally, the signal is transmitted to the analog-to-digital converter to complete analog-to-digital conversion and data acquisition. In addition, the entire circuit link effectively prevents power supply signal interference through reasonable power supply distribution and ground separation, ensuring the accuracy and stability of the signal during transmission and processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is a functional block diagram of a low-noise audio acquisition circuit based on an underwater glider according to Example 1 of the present invention;

[0020] Figure 2 Schematic diagram of a CMOS operational amplifier circuit according to embodiment 1 of the present invention;

[0021] Figure 3 Schematic diagram of a digital programmable gain amplifier circuit according to embodiment 1 of the present invention;

[0022] Figure 4 1 is a schematic diagram of a fully differential amplifier circuit according to embodiment 1 of the present invention;

[0023] Figure 5 4 is a schematic diagram of the analog-to-digital conversion circuit of Example 1 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects of the invention easier to understand, the present invention is further described with reference to specific figures. However, the present invention is not limited to the following implementation cases.

[0025] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0026] An embodiment of the present invention provides a low-noise audio acquisition circuit. This circuit system is integrated within the sealed cabin of an underwater glider and connected to the glider's main control circuit system via wires. Watertight cables connect it to a host computer system outside the cabin for debugging. Four hydrophones are located at the bow, tail, and wings of the glider. These hydrophones must pass through a non-vacuum cabin to connect to the audio acquisition circuit, and therefore are also connected via watertight cables. Because the audio signals collected by the hydrophones are already weak, and transmitted over long distances through watertight cables, the signals become even weaker and more susceptible to interference. To address this issue, a low-noise audio acquisition circuit was designed, along with a carefully designed data processing module.

[0027] Example 1:

[0028] like Figure 1 The low-noise audio acquisition circuit based on an underwater glider shown includes: a data interaction module, a data storage module, a processor module, a data processing module and a controller module;

[0029] The data interaction module is used to collect the status information of the underwater glider and send the status information to the data storage module; the status information is a digital signal collected by the digital sensor, including temperature, salinity, depth and other information, which reflects the status of the underwater glider.

[0030] The data processing module includes a hydrophone, an operational amplifier, a gain amplifier, and a fully differential amplifier; the analog signal collected by the hydrophone is valid audio information; the differential signal collected by the hydrophone, that is, the audio information, is first initially amplified and impedance matched by the operational amplifier, and then enters the gain amplifier for flexible gain adjustment and signal optimization, and then further amplifies the signal and suppresses common-mode interference through the fully differential amplifier, and finally transmits the differential signal to the analog-to-digital converter to complete the analog-to-digital conversion.

[0031] The processor module processes the received audio information and transmits the processed audio information to the data storage module;

[0032] The data storage module has two functions: one is to store the data obtained by the controller module, including the controller's work log and the information obtained by the digital sensor in the data interaction module; the other is to store the data obtained by the processor module, that is, the processed audio information.

[0033] The controller module is used to control each module and data transmission;

[0034] The data processing module is powered and controlled by an independent analog power supply.

[0035] The controller module is connected to the digital sensor in the data interaction module through the SPI (Serial Peripheral Interface) serial peripheral interface and UART (Universal Asynchronous Receiver / Transmitter), connected to the underwater glider main control circuit system in the data interaction module through UART, connected to the host computer system in the data interaction module through the CAN (Controller Area Network) controller area network bus, connected to the processor module through UART, and connected to the data storage module through the SDIO (Secure Digital Input and Output) secure digital input and output interface.

[0036] The controller module obtains external data through the data interaction module, including the information transmitted by the underwater glider main control circuit system, the information transmitted by the host computer system, and the information collected by the sensor.

[0037] The underwater glider's main control circuit system transmits information including time, current profile number, temperature, salinity, depth, etc. The host computer system transmits information for circuit system debugging. Users can debug and control the low-noise audio acquisition circuit through the host computer, and can control the low-noise audio acquisition circuit to start / stop data collection, update the program, etc.

[0038] The controller module transmits data to the processor module via UART, including information obtained from the underwater glider's main control circuit system and the host computer system, to control the working status of the processor module. The controller module stores the work log in the data storage module.

[0039] Specifically, the processor module is connected to the controller module via UART, connected to the data storage module via SDIO, and connected to the analog-to-digital conversion chip in the data processing module.

[0040] Specifically, the data storage module is used to store valid data of the controller module and the processor module, and is connected to a USB connector, through which the user can view the contents of the SD card.

[0041] Specifically, the data processing module includes four analog hydrophones, a multi-stage amplifier, and an analog-to-digital conversion chip, all powered by independent analog power supplies. The audio data collected by the four analog hydrophones is amplified and noise-reduced by a cascaded amplifier circuit before being transmitted to the analog-to-digital conversion chip. This converts the analog signals into digital signals and transmits them to the processor module.

[0042] like Figure 2-Figure 4 The figure shows the schematic diagram of the amplifier cascade circuit for the data processing module of the low-noise audio acquisition circuit. The amplifier cascade circuit includes a CMOS operational amplifier circuit, a digital programmable gain amplifier circuit, and a fully differential amplifier circuit. The RS6334 CMOS operational amplifier, with its high input impedance, serves as the first-stage amplifier. It receives differential signals from four analog hydrophones, amplifies the differential signal amplitude, and, combined with its high common-mode rejection ratio, suppresses noise interference, improves the signal-to-noise ratio, and converts the differential signal to a single-ended output. The LTC6911 digital programmable gain amplifier dynamically selects gain via a 3-bit DSP digital interface to address fluctuations in hydrophone signal strength and prevent high-frequency signal attenuation. It uses an inverting amplification mode to further amplify the RS6334 CMOS output signal. The THS4521 fully differential amplifier receives single-ended signals, provides twice the dynamic range, and outputs a fully differential signal for enhanced anti-interference performance. Its input pins are reversed to match the LTC6911 digital programmable gain amplifier's phase amplification mode. Its Vocm pin is set to output a common-mode voltage of 2.5V to match the input voltage of the analog-to-digital converter chip.

[0043] Specifically, the COMS operational amplifier circuit includes chip U1, resistors R1-R17, and capacitors C1-C11. Chip U1 is an RS6334XTQC16 COMS operational amplifier. Pin 2 of chip U1 is connected to a 5V analog power supply and is current limited by resistor R1. It is filtered by analog ground through capacitor C2. Pins 11 and 17 of chip U1 are connected to analog ground. Pins 1, 3, 4, 9, 10, 12, 13, and 16 of chip U1 are connected to the differential signals collected by the four-way hydrophone and are limited by resistors R4, R6, R7, R9, R10, R12, R13, and R15. The current is filtered through capacitors C3, C4, C5, C6, C7, C8, C9, and C10. Pins 1, 3, 10, and 12 of chip U1 are also connected to a 2.5V calibration voltage, and are limited by resistors R2, R3, R16, and R17, and filtered through capacitors C1 and C11 connected to analog ground. Pins 5, 8, 14, and 15 of chip U1 output four signals, and are limited by resistors R5, R8, R11, and R14. Pins 6 and 7 of chip U1 are left floating.

[0044] Specifically, the digital programmable gain amplifier circuit includes chips U2 and U3, resistors R18-R31, and capacitors C12-C19. Chips U2 and U3 are LTC6911CMS-1 digital programmable gain amplifiers. Pin 2 of chips U2 and U3 is connected to a 2.5V calibration voltage and is filtered through capacitors C14 and C17 to the analog ground. Pin 7 of chips U2 and U3 is connected to a 5V analog power supply and is current limited through resistors R18 and R31. It is filtered through capacitors C12 and C19 to the analog ground. Pins 4, 5, and 6 of chips U2 and U3 are connected to the DSP gain amplification control pins. Pins 1 and 3 of chips U2 and U3 are connected to the DSP gain amplification control pins. The four signals output by the 5, 8, 14, and 15 pins of chip U1 are connected, and the current is limited by resistors R19, R23, R25, and R29. The 1 and 3 pins of chips U2 and U3 are also connected to a 2.5V calibration voltage, and the current is limited by resistors R20, R24, R26, and R30. The 8 and 10 pins of chips U2 and U3 output four signals, and the current is limited by resistors R21, R22, R27, and R28, and the analog ground is filtered through capacitors C13, C15, C16, and C18.

[0045] Specifically, the fully differential amplifier circuit includes chips U4-U7, resistors R32-R59, and capacitors C20-C39. Chip U4-U7 is a THS4521IDGKR fully differential amplifier. Pin 2 of chip U4-U7 is connected to a 2.5 calibration voltage and is filtered through capacitors C21, C26, C31, and C36 to the analog ground. Pin 3 of chip U4-U7 is connected to a 5V analog power supply and is current limited through resistors R32, R39, R46, and R53. It is filtered through capacitors C20, C25, C30, and C35 to the analog ground. Pin 6 of chip U4-U7 is connected to the analog ground. Pin 8 of chip U4-U7 is connected to the four-way signal output of pins 8 and 10 of chips U2 and U3, and is current limited through resistors R36, R43, R50, and R57. Pin 1 of chip U4-U7 is connected to a 5V analog power supply and is current limited through resistors R32, R39, R46, and R53. It is filtered through capacitors C20, C25, C30, and C35 to the analog ground. R48 and R55 are connected to the analog ground. Pins 4 and 5 of chip U4-U7 output four sets of differential signals and are current limited by resistors R35, R37, R42, R44, R49, R51, R56 and R58. The positive and negative ends of the differential signals are filtered by capacitors C23, C28, C33 and C38. Pins 1 and 4 of chip U4-U7 are connected to capacitors C22, C27, C32 and C37 through resistors R33, R40, R47 and R54 to form a negative feedback circuit. Pins 5 and 8 of chip U4-U7 are connected to capacitors C24, C29, C34 and C39 through resistors R38, R45, R52 and R59 to form a negative feedback circuit. Pin 7 of chip U4-U7 is left floating.

[0046] like Figure 5 Figure 2 shows the schematic diagram of the analog-to-digital conversion circuit. The ADS1274 chip, as the final stage of the data processing chain, is responsible for converting the processed analog signal into a high-resolution digital signal. The ADS1274 chip's differential inputs receive the symmetrical signals output by the THS4521 amplifier. It uses its internal differential sampling circuit to further suppress common-mode noise, and its built-in linear phase filter suppresses out-of-band noise, preserving signals within the common underwater acoustic frequency band. Finally, the ADS1274 chip transmits the final processed data to the DSP in the processor module via the SPI interface.

[0047] Specifically, the analog-to-digital conversion circuit includes chips U8 and U9, resistors R60-R79, capacitors C10-C51, polarized capacitor CP1, crystal oscillator X1, and ferrite bead LB1. Chip U8 is an ADS1274IPAPR analog-to-digital conversion chip. Its analog positive terminal is connected to a 5V analog power supply, its digital positive terminal is connected to a 1.8V digital power supply, its analog negative terminal is connected to analog ground, and its digital negative terminal is connected to digital ground. Its eight input pins are connected to four pairs of differential signals output by the amplifier cascade circuit, and its four output pins output the processed digital signals to the DSP in the processor module. Chip U9 is an LT1019ACS8-2.5 voltage reference chip. Its positive terminal is connected to a 5V analog power supply, its negative terminal is connected to analog ground, and it outputs a 2.5V voltage to the reference voltage pin of chip U8. The positive terminal of crystal oscillator X1 is connected to a 1.8V digital power supply, and noise is filtered through ferrite bead LB1. It then outputs a fixed-frequency signal to the clock pin of chip U8.

[0048] The above content is the overall link in the data processing module. Through this link, complete conversion from μV-level acoustic signals to high-fidelity digital signals is achieved. Through reasonable power distribution and ground separation, power supply signal interference is effectively prevented, providing a reliable data foundation for DSP intelligent analysis.

Claims

1. A low-noise audio acquisition circuit based on an underwater glider, characterized in that: include: Data interaction module, data storage module, processor module, data processing module and controller module; The controller module is used to control each module and data transmission; the data storage module is used to store valid data transmitted by the controller module and the processor module; The data interaction module is used to collect status information of the underwater glider and send the status information to the data storage module; The data processing module includes an operational amplifier, a gain amplifier, a fully differential amplifier, and a hydrophone for collecting audio information; The audio information collected by the hydrophone is firstly amplified and impedance matched by the operational amplifier, then enters the gain amplifier for flexible gain adjustment and signal optimization, and then further amplifies the signal and suppresses common-mode interference by the fully differential amplifier, and finally transmits the audio information to the analog-to-digital converter for analog-to-digital conversion; The processor module processes the received audio information and transmits the processed audio information to the data storage module.

2. The low-noise audio acquisition circuit based on underwater glider according to claim 1, characterized in that: The data processing module is powered and controlled by an independent analog power supply.

3. The low-noise audio acquisition circuit based on underwater glider according to claim 1, characterized in that: The data storage module is connected to a USB connector, and a user can view the storage content of the SD card in the data storage module through the USB connector.

4. The low-noise audio acquisition circuit based on underwater glider according to claim 1, characterized in that: The data interaction module includes a host computer system for debugging and controlling the circuit, a digital sensor for collecting information such as temperature, salinity, depth, etc., and an underwater glider main control circuit system.

5. The low-noise audio acquisition circuit based on underwater glider according to claim 4, characterized in that: The controller module obtains external data through the data interaction module; the external data includes information transmitted by the underwater glider main control circuit system, information transmitted by the host computer system and information collected by sensors.

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