Design Of A Single Channel Self Contained Acoustic Acquisition System

The study of the acoustic scattering characteristics of the ocean interface and its influencing mechanism is an important part of the research of ocean water acoustics,and is also a leading scientific issue in the field of oceans today.In order to carry out the experimental measurement and research of the acoustic scattering characteristics of the ocean interface,with the support of the national major scientific research instrument development project "Development of the Measurement System of the Intermediate Frequency Acoustic Scattering Characteristics of the Ocean Interface",this paper takes the sub-topic of "Development of Acoustic Scattering Receive Submarine Subsystem" The design of a single-channel self-contained acoustic wave acquisition system is expanded.The single-channel self-contained acoustic wave acquisition system is the core of the acoustic scattering receiving submarine target subsystem.Therefore,the design of a single-channel self-contained acoustic wave acquisition system has important scientific research value.In this paper,the overall scheme of the single-channel self-capacity sonic acquisition system is proposed for the various technical indicators of receiving submarine acquisition nodes.The single-channel self-contained acoustic wave acquisition system mainly includes two parts: a broadband hydrophone and an acquisition storage module.As a sensor that receives acoustic signals,a wideband hydrophone converts the received reflected acoustic wave signals into electrical signals.This paper uses a wideband hydrophone,which can receive acoustic signals in the range of 1?20KHz.The collection and storage module digitally quantifies the electrical signals converted by the hydrophone,and uses the micro SD card to stably store the collected data.The main research contents of this article are as follows:According to the characteristics of the acoustic scattering signal at the ocean interface,a low-pass and high-pass filter amplifier circuit for the acquisition front end is designed.The high-speed 24-bit delta-sigma analog-to-digital converter and high-performance low-power microcontroller are used to achieve high-speed data acquisition and high performance.Storage,thereby improving the performance of acquisition storage.The self-contained sonic wave acquisition and storage system uses STM32F207 as the main control core,and uses the SDIO high-speed interface to transfer the stored data to the SD card.At the same time,it cooperates with the DMA channel to improve the real-time performance of the CPU and meet the requirements of the system's high-speed and large-capacity data;use SPI The hardware interface reads the AD7767 to complete the analog-to-digital conversion to realize the collection of ocean acoustic signals;the I2 C interface is used to obtain the system voltage and current information through the LTC2945 and the sampling frequency is controlled by the PLL of the CDCE913.Through the custom communication link layer protocol to ensure two-way reliable communication with the host computer.Considering the real-time requirements of the acquisition system,using the portable and tailorable Free RTOS real-time operating system,four tasks of a single-channel self-capacity acquisition and storage system are realized: data writing task,system working status uploading task,communication data parsing task and host Machine commands to process tasks.The data writing task is based on the transplantation of the FAT32 file system,completes the storage function of the data volume,and achieves a large data capacity of 128 GB through hardware design;the system work upload task obtains the operating voltage and current of the system operation to ensure that the device works normally;The communication data analysis task adopts a reliable finite state machine to realize the command reception.The received task table realizes the setting of the acquisition start time and sampling frequency;the host computer command processing task fulfills the command processing requirements.On the basis of hardware and software design,relevant tests were carried out.The test results show that the collection and storage system designed in this paper works normally and has low power consumption,which can provide data support for the follow-up research of the subject.