共查询到20条相似文献,搜索用时 171 毫秒
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摘要:基于相关检测原理设计了一种数字锁相放大器,重点研究了采样频率与相关运算结果的关系。发现参考信号为方波而采样频率与信号频率成一定关系时,系统相关运算存在固有误差。为减少该误差,首次将动态采样法引入数字锁相放大器设计中,运算发现动态采样的采样频率数越多,奇点产生的误差越少。基于LabVIEW软件对所设计的检测系统进行了仿真测试,测试结果表明该数字锁定放大器在信号幅度为5V、噪声标准差小于等于50时(SNR=-34.04dB),能有效地检测出频率为500KHz以下的信号,系统检测结果与理论计算值的相对误差基本不超过2%。 相似文献
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王倢婷 《数字社区&智能家居》2014,(26):6242-6245
为了获取高精度有效信号在信号检测系统中,常常需要进行滤波,将设置频率以外的信号彻底清除,数字滤波器广泛应用于各种测量系统。基于MATLAB的在线数字滤波器设计过程简单易行,不仅具有较高的精度和稳定性,还有运算速度快,延迟小的特点,可以满足测量要求。但在实际应用时如果采样数据长度选择不当,输出波形会出现失真。通过实验分析了采样数据长度与波形失真的关系,在使用时要兼顾误差与延迟,保证数字滤波测量精度。 相似文献
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《电子技术应用》2017,(9)
提出一种基于LMS(Least Mean Square)自适应算法的滤波方法,介绍该方法在低频信号滤波上的应用及在FPGA平台上实现。传统数字滤波器FIR、IIR滤波器针对不同的系统和干扰信号,其滤波参数不固定。因此,在窄带信号的滤波处理中,传统滤波器对信号滤波降噪的效果往往受到衰减增益限制。提出的方法先以CORDIC(Coordinate Rotation Digital Computer)算法产生的正弦信号来调制采样信号,根据采样信号与基准信号误差使其权向量沿负梯度方向终止于维纳解。该方法在类直流输入及带宽窄的情况下仍能有效过滤高频噪声,读取低检测信号幅值。理论分析和实验结果表明,与传统滤波方法对比,该滤波方法在处理窄带信号的滤波上更具有优势。 相似文献
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为了提高数字直放站回波抵消的收敛速度,首先研究了基于自适应滤波器的回波抵消技术,然后对其中的自适应滤波器的递推算法进行改进,形成了两个自适应滤波器并行计算、联合递推更新权值的技术方案。由于调节两个自适应滤波器权值的误差信号产生方式不同,方案可分为两种:方案一将回波抵消后的信号同时作为调节两个滤波器权值的误差信号(同时);方案二将天线接收信号与第一个滤波器输出信号的差值作为调节第一个滤波器权值的误差信号,而将该误差信号与第二个滤波器输出信号的差值作为调节第二个滤波器权值的误差信号(分别)。仿真结果表明,改进技术方案使回波抵消收敛速度提高11.11%~17.78%,从而有效改善了数字直放站回波抵消收敛速度慢的状况。 相似文献
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分析了嵌入式系统中信号采样,对信号进行滤波处理.讨论了滤波器在实际应用里的作用,如何削减干扰信号,增强有用信号.并详细介绍了数字滤波器的特点、分类和数字滤波器的设计方法.在线性时不变系统中,用Z变换来对系统进行滤波、补偿或控制,能很好地复制时域的问题. 相似文献
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考虑到带宽有限网络环境下信号需经过量化处理才能进行发送,研究了一类带宽受限随机网络控制系统的L_2-L_∞滤波问题。采用对数量化器,将量化后的测量信号作为滤波器输入信号。首先将滤波误差系统建模成范数有界不确定随机时滞系统,进一步基于线性矩阵不等式方法推出了该随机网络控制系统的稳定性和滤波器设计的充分条件,并将滤波器的设计转化为一个凸优化的求解问题。所设计的滤波器能够保证相对于所有能量有界的外界扰动信号,随机网络控制系统的L_2-L_∞性能指标小于一定值γ。仿真实例证实了该设计方法的有效性。 相似文献
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Fernando de Oliveira Souza Leonardo Amaral Mozelli Maurício Carvalho de Oliveira 《International journal of control》2016,89(10):1962-1971
In this paper, we propose a methodology for the design of networked PID controllers for second-order delayed processes using linear matrix inequalities. The proposed procedure takes into account time-varying delay on the plant, time-varying delays induced by the network and packed dropouts. The design is carried on entirely using a continuous-time model of the closed-loop system where time-varying delays are used to represent sampling and holding occurring in a discrete-time digital PID controller. 相似文献
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《Digital Signal Processing》2006,16(3):211-224
In this paper, a novel analytic technique is presented for the design of finite impulse response digital filters with simultaneous amplitude and phase requirements. The design process relies on the interpolation concept and is based on the generation of arbitrary amplitude and phase polynomials. The new class of FIR filters lays in between the exact linear phase filters at all frequencies and the minimum phase FIR filters based on the amplitude approximation only. It interpolates arbitrary (e.g., linear) phase response in the passband and arbitrary amplitude characteristics in pass- and stopbands. The introduced class of filters can be used on the amplitude and phase equalization of both FIR and IIR digital filters. Illustrative examples are included in order to investigate the main properties of these filters and to demonstrate that the proposed design method leads to a significant saving in the arithmetic computations. 相似文献
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This paper discusses the problem of optimal design of experimental conditions for linear system identification. It is demonstrated that, in general, to achieve maximal return from an experiment, coupled design of all the experimental conditions, namely the test signal, sampling intervals and filters, should be carried out simultaneously. For the case of uniform sampling it is shown that joint design of the presampling filter, sampling rate and input can be carded out in the frequency domain. For the case of nonuniform sampling a sequential design procedure is developed which optimizes the information increment between samples. 相似文献
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均匀线列阵时域宽带波束形成方法研究 总被引:2,自引:0,他引:2
时域宽带恒定束宽波束形成技术一般采用特殊频率响应的FIR滤波器组实现对不同频率的加权.对水下常用的均匀线列阵,利用切比雪夫方法设计了形成宽带恒定束宽波束的权值.通过对切比雪夫方法设计权值特性的分析,推导出实现加权的FIR滤波器组的相位响应关系式.根据推导结果得出设计的FlR滤波器组应为一组斜率不同的线性相位响应FIR滤波器.推导了滤波器组相位响应的计算公式.给出三种特殊频率响应FIR滤波器设计算法.通过仿真结果比较了三种方法设计的用于实现均匀线列阵恒定束宽加权的FIR滤波器组的性能. 相似文献
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YUICHI OHASHI HISASHI KANDO HIROYUKI UKAI TETSUO IWAZUMI 《International journal of systems science》2013,44(8):1469-1482
Many methods exist for designing FIR linear phase digital filters by using various optimization techniques. An optimization design method via the convex quadratic programming method is investigated in this paper. The aim of this method is to design digital filters with certain desired frequency responses that keep the passband ripple to a minimum while maintaining a balance between opposite characteristics of frequency responses, i.e. the narrow transition band and the great stopband attenuation. In order to verify the effectiveness of this method, low-pass filters are designed and comparison studies with other typical optimization methods are given. 相似文献
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The design and testing of an optimal PID automatic voltage regulator for synchronous machines is treated. The proposed digital PID regulator combines automatic voltage regulation with the function of a power system stabilizer. The PID and stabilizing signal parameters are optimized based on a linear quadratic performance index using the Simplex method. The design of the regulator is achieved directly without using a linearised mathematical model, and only impulse responses of the system are required during the optimization procedure. The microcomputer-based regulator with digital filters has been tested on a laboratory model turbogenerator system. Simulation and experimental results are presented, showing that the regulator provides very good performance, which is superior to that obtained with a conventional automatic voltage regulator with power system stabilizer. 相似文献
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The control of a linear time-invariant plant by a digital controller composed of a sampler, a periodic discrete-time component, and a zero-order hold is considered. The stability of such a configuration is analyzed. It is shown how closed-loop zeros can be placed using such a scheme. As a consequence, it is proved that the gain margin can be arbitrarily assigned by suitable choice of sampling time and digital controller. The design procedure is constructive, using state-space methods 相似文献