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基于DDS的信号发生器 总被引:1,自引:0,他引:1
本文设计一种基于直接数字频率合成技术(DDS)的信号发生器。系统由SPCE061A单片机产生命令控制字和10kbps码元,AD9850产生正弦信号和FM信号,利用模拟开关4051实现调制度ma的程控和ASK/PSK信号。该系统具有波形失真度小,频率范围大且稳定等特点。 相似文献
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针对传统的定点开关控制温度会有误差的现象,设计了一种水温控制系统,以SPCE061A为核心控制器,结合Pt100传感器进行水温采集,并且对采集到的温度值进行PID运算处理,实现了对水温的控制. 相似文献
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随着智能电网建设及电力系统自动化、智能化水平的不断提高,电力系统信号分析与数据处理方法在电力系统中的重要作用进一步凸显。压缩传感(CS)是一种基于信号的稀疏特性,将利用奈奎斯特采样定理的信号采样过程转化为基于优化计算恢复信号的观测过程的新兴信号处理方式,并广泛应用于信号/图像处理、医疗成像与无线通信等领域。基于压缩传感的电力系统信号分析与数据处理方法具有采样速率低、高压缩比,以及便于提取信号特征等优点,因而,在电力系统中具有广泛的应用前景。描述了压缩传感理论框架,并对该理论在电力系统信号分析与数据处理中的应用进行详细综述,其中主要围绕电能质量分析、故障分析、电力系统模态识别、电力系统预测、数据传输,以及智能电网等方面进行评述,并结合压缩传感在电力系统信号分析与数据处理领域的发展状况,对其发展前景进行展望。 相似文献
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为了解决船用设备运行的可靠性这一问题,在工控机等硬件设备上开发了基于C#平台的船用机械故障诊断系统。首先,构建了工控机、信号调理器等硬件组成部分;在此基础上,采用C#编制了采集卡接口、信号处理方法、图形绘制等程序;最后进行了调试并应用于船用现场试验。结合齿轮故障设备模拟试验台,运用故障诊断系统采集信号,利用信号处理软件分析了正常齿轮与磨损齿轮的时域波形和频谱波形,分析了断裂齿轮的细化频谱的边频带,以此识别出了各类齿轮失效所在位置和原因。研究结果表明,船用机械设备故障诊断系统对于故障齿轮的检测具有有效性和可行性,同时该结果为利用故障诊断系统对轴承、柴油机等其他故障设备的诊断开发过程奠定了基础。 相似文献
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研究一种基于已知信号模型的相量快速同步测量算法.这种算法在已知信号模型的基础上,通过确定时间间隔的采样值求取相量参数,计及了衰减直流分量,计算速度快,能够在电力系统故障和振荡情况下测量电压电流相量参数,适用于同步相量测量单元(PMU)和继电保护装置.算例表明,算法正确有效,计算速度和精度令人满意. 相似文献
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Early bearing faults can generate a series of weak impacts. All the influence factors in measurement may degrade the vibration signal. Currently, bearing fault enhanced detection method based on stochastic resonance(SR) is implemented by expensive computation and demands high sampling rate, which requires high quality software and hardware for fault diagnosis. In order to extract bearing characteristic frequencies component, SR normalized scale transform procedures are presented and a circuit module is designed based on parameter-tuning bistable SR. In the simulation test, discrete and analog sinusoidal signals under heavy noise are enhanced by SR normalized scale transform and circuit module respectively. Two bearing fault enhanced detection strategies are proposed. One is realized by pure computation with normalized scale transform for sampled vibration signal, and the other is carried out by designed SR hardware with circuit module for analog vibration signal directly. The first strategy is flexible for discrete signal processing, and the second strategy demands much lower sampling frequency and less computational cost. The application results of the two strategies on bearing inner race fault detection of a test rig show that the local signal to noise ratio of the characteristic components obtained by the proposed methods are enhanced by about 50% compared with the band pass envelope analysis for the bearing with weaker fault. In addition, helicopter transmission bearing fault detection validates the effectiveness of the enhanced detection strategy with hardware. The combination of SR normalized scale transform and circuit module can meet the need of different application fields or conditions, thus providing a practical scheme for enhanced detection of bearing fault. 相似文献
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SIGNAL FEATURE EXTRACTION BASED UPON INDEPENDENT COMPONENT ANALYSIS AND WAVELET TRANSFORM 总被引:1,自引:0,他引:1
Ji Zhong Jin Tao Qin Shuren College of Mechanical Engineering Chongqing University Chongqing China 《机械工程学报(英文版)》2005,18(1):123-126
It is an important precondition for machine fault diagnosis that vibration signal can be extracted effectively. Based on the characteristic of noise interfused during the course of sampling vibration signal, independent component analysis (ICA) method is combined with wavelet to de-noise. Firstly, The sampled signal can be separated with ICA, then the function of frequency band chosen with multi-resolution wavelet transform can be used to judge whether the stochastic disturbance singular signal is interfused. By these ways, the vibration signals can be extracted effectively, which provides favorable condition for subsequent feature detection of vibration signal and fault diagnosis. 相似文献
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针对电动变桨系统中常见的电流传感器故障,提出一种基于单电流检测的电动变桨系统变论域模糊容错控制方法。当变桨系统发生单个或两个电流传感器故障时,该方法利用直流母线电流传感器对所缺失的电流信息进行重构,保证三相电流能在任意两个相邻采样周期内得到及时更新,确保闭环系统稳定,并通过自适应阈值故障判断法完成故障相电流传感器的切换及容错。针对调制法引起的重构信号误差及电动变桨系统的主要控制目标,将变论域模糊控制方法应用于速度环,以改善系统抗负载扰动能力,提高容错系统鲁棒性。结果表明,该容错控制方法使得变桨系统在传感器故障情况下,牺牲部分系统性能后依然具有较理想的控制特性,并且该方法的正确性也得到了验证。 相似文献