频率编码水声数字遥控系统与海床基海洋环境监测系统水下状态监测仪发射机的研制

本论文分为两部分： 第一部分是频率编码数字遥控系统的研制。该系统发射部分采用四个频率编码设计了6个遥控指令，为提高抗干扰能力而以移频键控数字调制方式调制发射信号，通过8031单片机控制给可预置分频器置数产生信号。接收部分以8031单片机为核心，采用测周期的方法测量信号的频率，根据频率的先后组合而解码。通过重复发射，累加定时判断，辅以严密的解码逻辑提高系统的检测概率，降低虚警概率。特别在信号处理中提出实现了一种阻塞的方法，使多途、噪声在一定时间内不能进入测频部分，以最大可能的降低多途、噪声对系统的干扰，使系统具有较好的抗多途、抗噪声能力。理论分析与实验表明该系统的检测概率较高，虚警概率非常低，...学位：理学硕士院系专业：海洋与环境学院_海洋物理学号：19962700

用单片机实现脉码调制的频移键控(PCM—FSK)信号

本文介绍用单片机实现脉码调制频移键控信号（PCM—ASk）的方法，给出硬件和软件配置，其特点是简单、可靠、精确，适合用于传输水声信息

基于LabVIEW的海洋声学仪器信号识别方法

在总结几种常用海洋声学仪器的基本原理以及信号特征基础上,提出了采用频谱分析和自相关方法提取噪声中的信号频率、脉宽、周期信息,采用短时傅里叶变换提取海洋声学仪器信号的时-频特征值的方法,并与相关的海洋声学仪器信号参数数据库比对,设计了信号识别方法。基于lAbVIEW软件构建了一套几种常用海洋声学仪器的信号识别系统,给出了识别系统的软件操作界面。通过应用实测AdCP数据和仿真信号源所产生的几种声学仪器信号进行信号识别检验,表明该系统能够在较低的信噪比条件下准确的识别已知特征参量的海洋声学仪器信号。研究成果可用于检测海洋中声学仪器的工作状态,识别不同海洋声学仪器。科技部科技创新项目资助;福建省科技重点项目(NO:2009N0050

A Wide Band-Pass Filter

本文介绍一种由四参差调谐回路和反相输入模拟加法器构成的宽响应带通滤波器，并给出电路结构，实验测试和结果。In this paper,a band-pass filter with wide response is described,which is composed of four uneventuning ciruits and one inverting adder,and the circuit construction and the testing results are given too

Some Measures fou Anti-Multipath Interference to Underwater Acoustic Remote-Controlled Command by Frequency Code

浅海信道中，多途干扰是水声遥控指令可靠检测的首要障碍，本文探讨频率编码遥控指令的抗多途对策，即通过阻塞多途来削落多途干扰。Multipath interference hinders chiefly from detecting reliably an underwater acoustic reomte-controlled command in shallow-water channels.Some measures of anti-multipath interference are discussed on a remote-controlled command by frequency code in this paper,that is,multipath carriers are blocked off in the receiving circuits to remove multipath interference

Research on Anti Signal Fluctuation for Detecting Pulse Position Information in Shallow Water Acoustic Channels

浅海声信道中脉位信息的精确检测是较为困难的，它必须克服强多途、大起伏和高噪声的严重干扰.着重分析浅海声信道中信号振幅和重复周期起伏的主要特性及其对脉位信息精确检测的影响，指出克服信号起伏的可能的途径.所讨论的内容对其他的信号检测方式具有参考价值.It is relatively difficult that the pulse position information is detected exactly in shallow water acoustic channels,which has to overcome the severe interference coming from strong multipath,large fluctuation and high noise.The main characteristics of fluctuation for signal amplitudes and repetition periods,and their effects on detection of the pulse position infonmation are analysed .The possible ways to overcome signal fluctuation are proposed.The discussed contents in the present work are of referenca value to other mode of signal detection in principle.福建省自然科学基

A Marine Acoustic Instruments Signal Recognition Method Based on BP Neural Network

分析了几种常用海洋声学仪器信号的基本特征,提出一种基于误差反向传播(bACk PrOPAgATIOn,bP)神经网络,以实现对信号特征参数进行分类、识别的方法.该方法采用短时傅里叶变换提取信号特征参数,运用lEVEnbErg-MArQuArdT算法训练bP神经网络.以实测海洋声学仪器信号的特征参数进行训练后,采用实测和仿真样本对bP神经网络的识别能力进行测试.实验结果表明,bP神经网络能够有效地区分不同海洋声学仪器的信号,识别准确率达到95%以上,且虚警率低于5%.该研究成果可用于识别海域中不同海洋声学仪器,检测海洋中声学仪器的工作状态.该识别方法对于其他海洋声信号的识别研究也有一定的参考价值.This paper analyzes the basic characteristics of several familiar marine acoustic instruments' signals,and presents a BP neural network(BPNN) based method for signal recognition and classification,which uses short time fourier transform(STFT) for characteristics extraction,and Levenberg-Marquardt algorithm for BPNN training.After training with real acoustic signals,we evaluate the classification ability of BPNN with real and simulated samples.Experimental results show that BPNN is able to categorize different marine acoustic instruments efficiently,and the recognition accuracy is more than 95% while the false alarm probability is less than 5%.In general,this method can be used to identify a variety of marine acoustics instruments and detect their working status.Also,it may provide references for recognizing other marine acoustic signals.国家自然科学基金项目(41176032);国家科技支撑计划项目(2008BAC50B02

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements