Study of CMOS integrated signal processing circuit in capacitive sensors

A CMOS integrated signal processing circuit based on capacitance resonance principle whose structure is simple in capacitive sensors is designed. The waveform of output voltage is improved by choosing bootstrap reference current mirror with initiate circuit, CMOS analogy switch and positive feedback of double-stage inverter in the circuit. Output voltage of this circuit is a symmetric square wave signal. The variation of sensitive capacitance, which is part of the capacitive sensors, can be denoted by the change of output vohage＇s frequency. The whole circuit is designed with 1.5 μm P-weU CMOS process and simulated by PSpice software. Output frequency varies from 261.05 kHz to 47. 93 kHz if capacitance varies in the range of 1PF - 15PF. And the variation of frequency can be easily detected using counter or SCU.

Long term integration of radar signals with unknown Doppler shift for ubiquitous radar

Ubiquitous radar is a new radar system that provides continuous and uninterrupted multifunction capability within a coverage volume. Continuous coverage from close-in ＂pop-up＂ targets in clutter to long-range targets impacts selection of waveform parameters. The coherent processing interval （CPI） must be long enough to achieve a certain signal-to-noise ratio （SNR） that ensures the efficiency of detection. The condition of detection in the case of low SNR is analyzed, and three different cases that would occur during integration are discussed and a method to determine the CPI is presented. The simulation results show that targets detection with SNR as low as -26 dB in the experimental system can possibly determine the CPI.

Design and Construction of a Digital Multichannel Analyzer for HPGe Detector Using Digital Signal Processing Technique

The outstanding advantage of digital signal processing (DSP) techniques and Field Programmable Gate Array (FPGA) technology is capable of improving the quality of the experimental measurements for nuclear radiation. In this article, a compact DMCA 8 K was designed and manufactured using DSP technique based on FPGA technology. In particular, the output of the preamplifier is completely processed by digital techniques which are obtained from the analog-to-digital converter (ADC) to calculate the baseline, DC offset, energy peaks, pile up, threshold discrimination and then the form of energy spectrum. The Spartan-6 board is used as a hardware for the development of the digital multichannel analyzer (DMCA), which is equipped with the 14-bit AD6645 with 62.5 Msps sample rate. The application software for instrument control, data acquisition and data processing was written under C++ builder via the RS-232 interface. The designed DMCA system has been tested with a HPGe detector using gamma sources of 60Co and 137Cs and a reference pulser.

Improvement of Boxcar Integrator and Its Application to Low Resistance Measurement of Inductive Load Coil

A boxcar integrator is described which is suitable for the low-repetition-rate signal processing. This boxcar integrator, named fixed-interval mode boxcar integrator, is able to reject harmonics other than the first harmonic component. It can also decrease the effective time constant In many situations, the antialiasing filter with narrow bandwidth will cause distortion of the input signal. The fixed-interval mode boxcar integrator with suitable gate width can achieve relative high performance without signal distortion because the bandwidth of its antialiasing filter can be wider than that in the fixed-Point boxcar integrator. ms boxcar integrator is used as majn part of signalprocessing circult in the low resisance measurement of inductive load coil. The results of experiments show that the fixed-interval boxcar integrator is suitable for low-repetition-rate use.

The integrated monitoring system for running parameters of key mining equipment based on condition monitoring technology

An integrated monitoring system for running parameters of key mining equipmenton the basis of condition monitoring technology and modern communication networktechnology was developed.The system consists of a client computer with functions ofsignal acquisition and processing, and a host computer in the central control room.Thesignal acquisition module of the client computer can collect the running parameters fromvarious monitoring terminals in real-time.The DSP high-speed data processing system ofthe main control module can quickly achieve the numerical calculation for the collectedsignal.The signal modulation and signal demodulation are completed by the frequencyshift keying circuit and phase-locked loop frequency circuit, respectively.Finally, the signalis sent to the host computer for logic estimation and diagnostic analysis using the networkcommunication technology, which is helpful for technicians and managers to control therunning state of equipment.

Multi-subpulse process of large time-bandwidth product chirp signal

To prevent the long-time coherent integration and limited range window stumbling blocks of stretch processing and reduce computational complexity, a novel method called multi-subpulse process of large time-bandwidth product linear frequency modulating （ LFM ） signal （ i. e. chirp ） is proposed in this paper. The wideband chirp signal is split up into several compressed subpulses. Then the fast Fourier transform （FFT） is used to reconstruct the high resolution range profile （ HR- RP） in a relative short computation time. For multi-frame, pulse Doppler （PD） process is performed to obtain the two-dimension range-Doppler （R-D） high resolution profile. Simulations and field ex- perimental results show that the proposed method can provide high-quality target profile over a large range window in a short computation time and has the promising potential for long-time coherent in- tegration.

Digital synthesis of programmable photonic integrated circuits

Programmable photonic waveguide meshes can be programmed into many different circuit topologies and thereby provide a variety of functions.Due to the complexity of the signal routing in a general mesh,a particular synthesis algorithm often only accounts for a specific function with a specific cell configuration.In this paper,we try to synthesize the programmable waveguide mesh to support multiple configurations with a more general digital signal processing platform.To show the feasibility of this technique,photonic waveguide meshes in different configurations(square,triangular and hexagonal meshes)are designed to realize optical signal interleaving with arbitrary duty cycles.The digital signal processing(DSP)approach offers an effective pathway for the establishment of a general design platform for the software-defined programmable photonic integrated circuits.The use of well-developed DSP techniques and algorithms establishes a link between optical and electrical signals and makes it convenient to realize the computer-aided design of optics–electronics hybrid systems.

Research on Network-based Integrated Condition Monitoring Unit for Rotating Machinery

In this paper, a network-based monitoring unit for condition monitoring andfault diagnosis of rotating machinery is designed and implemented. With the technology of DSP(Digital signal processing) , TCP/IP, and simultaneous acquisition, a mechanism of multi-process andinter-process communication, the integrating problem of signal acquisition, the data dynamicmanagement and network-based configuration in the embedded condition monitoring system is solved. Itoffers the input function of monitoring information for network-based condition monitoring and afault diagnosis system.

基于STM32的智能航行系统设计

为解决航行器智能确定航向并航行的问题,本文采取模块化的思想设计了一款基于STM32的红外导引的智能航行控制系统。该智能航行系统利用红外接收模块进行红外导引信号的接收,采取线性加权法进行航向与导引信号之间的偏离角确定,利用比例-积分-微分(proportion-integration-differentiation,PID)控制算法对控制舵机转角的脉冲宽度调制(pulse width modulation,PWM)信号的占空比进行确定,从而对螺旋桨的转速与舵桨的转角进行可靠控制。根据水池测试结果,该智能航行控制系统能够对红外接收信号进行快速处理,在保持较高航速的条件下进行可靠的航行控制。

研究生专业技术课程科教融合的创新实践探索--以微弱信号检测与处理课程为例

研究生教育是我国高等教育体系的重要组成部分,肩负着培养具备创新能力的科技领域人才的神圣使命。在新工科背景下,如何实现课堂教学与科学研究融合、达到学术素养和工程能力共同提升的培养目标,已成为高校教育教学改革面临的新课题。该文选取北京航空航天大学仪器科学与技术和光学工程两个一级学科开设的专业技术课微弱信号检测与处理,阐述在研究生专业技术课程教学中,通过融入本学科在国内具有影响力和技术优势的光纤陀螺、光纤电流互感器、空芯光纤微弱散射光检测三个典型科研实例,进行科教融合、提高教学质量的创新实践探索。

智能传感技术在水肥一体系统中的应用研究

以进一步提升水肥一体机系统的作业效率为目标,选取智能传感的监测技术,针对整机的监测控制与信号处理展开应用设计研究。考虑水肥一体机过程作业肥液融合的均匀性及系统各模块之间的协同性功能实现,结合微分补偿的传感数据算法处理方法,进行智能传感的水肥一体机架构布局,并匹配可执行的软件控制程序及硬件实施结构,进行实地传感应用监测与灌施控制作业试验。结果表明:水肥一体机系统的数据监测准确率可达95.25%,系统故障率相对降低3.79%,监测数据准确及时,能够确保系统各环节指令得到有效的调整与反馈,进而保证灌施土壤的含水稳定率相对提升7.87%,对于作物的稳定生长与产量提升有重要的参考价值。

LPI radar signal detection based on radial integration of Choi-Williams time-frequency image

This paper mainly revolves the time-frequency image of low probability of intercept(LPI) radar signals and carries out research work on image features selection and extraction and recognition. Since Choi-Williams distribution(CWD) uses the exponential kernel of bilinear generalized class of time-frequency distribution, it has an excellent time-frequency aggregation. And it is suitable for detecting LPI radar signals in a low signal-to-noise ratio(SNR) condition. A radial integration method based on the integral rotating factor is proposed to detect LPI radar signals when the signals' time-frequency image is obtained. First, the digital image processing method is used to preprocess the LPI radar signals' time-frequency images after CWD transformation; then, the radial integration method based on the integral rotating factor is used to detect LPI radar signals in the binary images. The analytic results of real data show that the method has a good performance on detecting LPI radar signals in a low SNR condition. Additionally,the method is simple and takes less logic resources and has the potential of real-time detection of LPI radar signals.

基于通感一体化技术的远距离感知与高精度测角系统开发

该文基于通感一体化技术,致力于开发一套远距离感知与高精度测角系统。通过深入研究通感一体化技术,以及感知信号处理算法包括距离估计、CFAR检测和角度估计等关键技术,实现对目标的准确感知和测角。系统的设计与硬件实现考虑感知系统架构、硬件配置与选型等方面,旨在提供高效、可靠的系统性能。实验结果表明,该系统在远距离感知和测角方面取得显著成果,为相关领域的研究和应用提供有力支持。

利用部分可信信号的导航终端欺骗干扰检测方法

导航信号认证服务处于初步部署阶段,认证信号对地覆盖重数无法满足独立定位授时需求,现有研究对这一阶段利用部分通过认证的信号,即可信信号,实现欺骗检测的方法关注度较低。针对这一现状,该文根据欺骗攻击原理,提出以可信信号为基准,基于可信信号伪距残差的欺骗检测方法,建立该场景下的欺骗检测模型,并分析影响所提方法检测性能的因素。经过仿真,在可信卫星数目为3颗、用户定位精度约10 m条件下,当欺骗导致的定位偏差为100 m时,该方法的平均欺骗检测概率可达0.96。此外,该文对算法欺骗检测盲区进行了分析,证明所提算法对于绝大部分欺骗导致的定位结果均有效。

基于原型滤波器的OTFS通感一体信号技术

随着无线技术的快速发展,无线设备呈现爆炸式增长趋势,导致频谱资源日益稀缺,雷达和通信频段不断重叠。为了避免无线通信和雷达感知之间的相互干扰,学术界广泛研究了通信感知一体化(Integrated Sensing and Communication,ISAC)技术,并且重点关注了正交时频空(Orthogonal Time Frequency Space,OTFS)信号。OTFS信号具备实现无线通信与雷达感知一体化的潜力。然而,分数多普勒会抬高OTFS多普勒旁瓣,引起多普勒弥散效应,不仅在通信数据与通信数据之间、通信数据与雷达数据之间产生严重干扰,还将导致微弱目标被强目标旁瓣淹没,进而影响雷达探测概率和通信信道估计精度,恶化整体性能。针对分数多普勒导致的OTFS性能下降问题,提出了基于原型滤波器的OTFS通感一体化信号设计方法。通过原型滤波器调理多普勒旁瓣,在不显著损失多普勒分辨率的同时,抑制多普勒弥散效应,提升检测概率,降低误码率。针对OTFS互相关匹配滤波信道估计算法计算复杂度高等问题,进一步提出了利用恒虚警率(Constant False Alarm Rate,CFAR)检测进行信道估计的思路,在降低计算复杂度的同时,稳健检测出了同一时延、不同多普勒的多个目标,保障了信道估计和目标检测性能。依据理论分析和仿真实验可知,本文可将分数多普勒条件下的通信误码率降低2个数量级。

集成多路单道能谱仪设计与信号处理

为满足核燃料间隙与核燃料富集度检测的需求,设计集成多路单道能谱仪。采用多阳极光电倍增管读出芯片MPR2进行前端信号成形和甄别,使用FPGA进行控制和计数,通过ARM处理器发送给上位机进行显示。实验测试结果表明,采用该方法设计的能谱仪在脉冲信号在300 kHz以下时计数误差为±1,能谱仪最大计数率可达5 MHz。该设备自2018年在核燃料棒富集度检测系统运行至今表现稳定,可谱仪满足核燃料间隙与核燃料富集度检测设计的要求。

集成互注入半导体激光器的微波光子学应用

光源是微波光子(microwave photonic,MWP)系统的“发动机”,从根本上决定了系统性能的上限。光注入半导体激光器集聚诸多优势,但离散器件引发的系统集成度低、结构复杂、体积大、稳定性差等弊端明显,大大限制了MWP系统的工程化应用。集成化是解决目前MWP技术实用化等瓶颈问题的关键,轻量级、高性能、多功能的激光器光源是集成MWP系统的关键。基于此,本文综述了近年来集成互注入半导体激光器在高效电光转换、微波信号产生、MWP变频、弱信号探测以及光学频率梳源等MWP应用方面的创新研究,期望为集成MWP系统提供可行的高性能集成光源,推动集成MWP技术的工程化应用尽快实现。

轻型无人机无源定位系统的信号处理板设计

无人机无源定位系统可借助广播电视信号实现对目标的双基无源定位,其中信号处理板的性能直接决定着定位精度。为适应轻型无人机平台,保证定位测量精度,本文设计了一款小型化的信号处理板。首先,对信号处理板的传统架构进行精简优化,采用FPGA+AD9467为信号处理的总体架构。为解决小型化设计带来的信号完整性问题,在设计全过程依托Cadence及HFFS仿真软件对信号完整性进行仿真分析,从反射、串扰、电磁屏蔽等方面入手,保障处理板的信号完整性。为提高处理板信号解析能力,在传统FFT频谱测量的基础上,设计了基于Blackman窗函数的四谱线差值算法。并用该算法对处理板接收信号的频谱特性进行测试,降低了频谱泄露和栅栏效应引起的测量误差,提高了测量精度。对信号处理板关键性能测试,其在29.5 kHz带宽内的SNR优于90 dB,SFDR优于75 dB。测试结果表明:所设计小型化信号处理板的信号处理能力表现优异,满足轻型无人机无源定位的应用场景。

基于OBE理念的“双线混融”教学模式改革研究——以《语音信号处理》课程为例

本研究以《语音信号处理》课程为例,探讨基于OBE(Outcome-Based Education)理念的“双线混融”教学模式改革。传统的教学模式强调知识的传授,存在知识单一、缺乏实际应用和互动性差等问题;而OBE理念注重学生的能力培养和实践应用能力的提升。本研究提出一种基于OBE理念的“双线混融”的教学模式,在课堂教学与实践环节中相互支持,促进学生的综合能力发展。实践结果表明,采用“双线混融”教学模式后,学生的学习动力和学习效果有明显的提升。学生能够更好地理解和应用语音信号处理相关知识,提高解决问题和实践操作能力。

基于SiP技术的信号处理通道设计

随着军用无人机等航电系统不断朝着小型化、智能化、综合化的方向发展,如何有效满足装备的低SWaP(Size,Weight and Power)要求成为一大难题。介绍了某型宽带综合化数字预处理模块的研制,利用“裸芯片+高密度基板”系统级封装(SiP)的方式对信号处理平台(DSP、FPGA、SerDes和DDR芯片)进行集成,替代目前业界普遍采用的“封装芯片+印制板+平面集成”的传统方式,实现宽带综合化数字信号处理模块的高密度集成。在主要性能指标(可编程逻辑资源、定点处理能力、浮点处理能力、数据传输速率)不变的情况下,使得信号处理模块的面积降低为45 mm×45 mm,重量降低到103 g。