共查询到20条相似文献,搜索用时 671 毫秒
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This paper proposes a hybrid active filter for the damping of harmonic resonance in industrial power systems. The hybrid filter consists of a small-rated active filter and a 5th-tuned passive filter. The active filter is characterized by detecting the 5th-harmonic current flowing into the passive filter. It is controlled in such a way as to behave as a negative or positive resistor by adjusting a feedback gain from a negative to positive value, and vice versa. The negative resistor presented by the active filter cancels a positive resistor inherent in the passive filter, so that the hybrid filter acts as an ideal passive filter with infinite quality factor. This significantly improves damping the harmonic resonance, compared with the passive filter used alone. Moreover, the active filter acts as a positive resistor to prevent an excessive harmonic current from flowing into the passive filter. Experimental results obtained from a 20-kW laboratory model verify the viability and effectiveness of the hybrid active filter proposed in this paper 相似文献
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Multiresolution Bilateral Filtering for Image Denoising 总被引:3,自引:0,他引:3
《IEEE transactions on image processing》2008,17(12):2324-2333
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A new odd-symmetric filter for ISI suppression and VSB transmission is proposed. The frequency response of the proposed filter is similar to that of an ideal raised-cosine filter, but in contrast to raised-cosine the new filter is realizable, e.g. using simple active filters. Simulation results show that concerning ISI suppression the new filter is significantly more efficient than the classical Butterworth or Chebyshev filters. The proposed filter can be also used as a VSB filter for TV modulators and demodulators. 相似文献
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Dual-band bandpass filters using equal-length coupled-serial-shunted lines and Z-transform technique 总被引:3,自引:0,他引:3
Lin-Chuan Tsai Ching-Wen Hsue 《Microwave Theory and Techniques》2004,52(4):1111-1117
A synthesizing method is presented to design and implement digital dual-band filters in the microwave frequency range. A dual-band filter consists of a bandstop filter and a wide-band bandpass filter in a cascade connection, wherein the transfer functions of both the bandpass filter and bandstop filter are expressed in the Z domain. The bandstop filter is implemented by using a coupled-serial-shunted line structure, while the wide-band bandpass filter is constructed by using a serial-shunted line configuration. In particular, the bandwidth of each passband of the dual-band filter is controllable by adjusting the characteristics of both the bandpass filter and bandstop filter. By neglecting the dispersion effect between microstrip lines of different widths over a wide bandwidth, a dual-band filter is realized in the form of microstrip lines and its frequency responses are measured to validate this method. 相似文献
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LCL滤波器在并联型有源电力滤波器中的设计 总被引:1,自引:0,他引:1
在满足相同的高频滤波效果的情况下,LCL滤波器所需的总电感值比L滤波器小,因此更适于在大功率、开关频率较低的电流源控制型并网设备上应用。然而针对该类型滤波器的参数设计不仅关系到开关频率处纹波抑制效果,同时也会影响电流控制器的性能。随着高频谐波抑制效果明显的LCL滤波器在并联型有源滤波器中应用,基于谐波电流跟踪控制器的LCL参数设计需要进一步研究,因此文中基于并联型有源电力滤波器给出一套LCL滤波器设计方法,并通过仿真验证该LCL滤波器的有源电力滤波器的有效性。 相似文献
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In this paper, an error compensation technique for a dead reckoning (DR) system using a magnetic compass module is proposed. The magnetic compass‐based azimuth may include a bias that varies with location due to the surrounding magnetic sources. In this paper, the DR system is integrated with a Global Positioning System (GPS) receiver using a finite impulse response (FIR) filter to reduce errors. This filter can estimate the varying bias more effectively than the conventional Kalman filter, which has an infinite impulse response structure. Moreover, the conventional receding horizon Kalman FIR (RHKF) filter is modified for application in nonlinear systems and to compensate the drawbacks of the RHKF filter. The modified RHKF filter is a novel RHKF filter scheme for nonlinear dynamics. The inverse covariance form of the linearized Kalman filter is combined with a receding horizon FIR strategy. This filter is then combined with an extended Kalman filter to enhance the convergence characteristics of the FIR filter. Also, the receding interval is extended to reduce the computational burden. The performance of the proposed DR/GPS integrated system using the modified RHKF filter is evaluated through simulation. 相似文献
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《Microwave Theory and Techniques》2006,54(10):3765-3771
A novel analytical filter diagnosis technique based on the partial fraction expansions of admittance matrix is proposed in this paper. The technique is applicable to computer-aided filter tuning of a general Chebyshev filter. The key issue in the proposed technique is the extension of the realizability conditions to the asynchronously tuned filters for removing the phase-loading effect. Using this analytical diagnosis technique, the inherent dispersion effects of the resonators and coupling elements are compensated by removable stray couplings in the diagnosed filter models. The filter topology that can be handled by this technique is only limited by the availability of the exact filter synthesis technique with which the filter to be diagnosed is designed. 相似文献
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边缘相似度及其在散斑噪声抑制算法比较中的应用 总被引:3,自引:0,他引:3
对于滤波算法,噪声抑制能力和边缘保持能力一直是考核其性能的两个重要指标。对于前者,通常都有相应的参数进行表征,而对于后者,通常却只能依靠人眼进行主观评判。根据标准边缘图像和待测边缘图像边缘点位置的相似性,定义了边缘相似度参数,用来表征滤波算法的边缘保持能力。将此参数应用于高斯噪声图像和椒盐噪声图像滤波算法的比较中,取得了预期的效果:此参数值准确地反映了各滤波算法的边缘保持能力。对激光雷达图像而言,散斑噪声滤波算法的边缘保持能力具有非常重要的意义,为此,将边缘相似度用于散斑噪声滤波算法的边缘保持能力比较,结果表明Lee滤波算法和增强Lee滤波算法具有较强的边缘保持能力,而常规的均值滤波和中值滤波边缘保持能力较差。 相似文献
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在宽带/窄带兼容的数字接收机中,匹配滤波器一般需要前置级联积分梳状(CIC)滤波器。在高性能要求的系统中,还需要对CIC进行补偿。传统的方法是将CIC补偿滤波器和匹配滤波器分开设计,而本文提出了一种将两者合并,使用一个滤波器来实现两种功能的方法。在不增加滤波器阶数的情况下,这种方法可以得到更好的滤波器性能,同时又节约了硬件资源。 相似文献
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一种C波段大功率谐波滤波器的设计 总被引:1,自引:0,他引:1
介绍了在大功率要求下一种C波段谐波滤波器的设计方法,采用漏壁式低通滤波方式,结构上分为主波导和副波导阵。该滤波器通带内电压驻波比小,插入损耗低。该设计使得滤波器耐功率高,可靠性好,可适用于多种大功率侦察设备。 相似文献
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在目标跟踪中,为了克服粒子滤波的粒子退化和贫化问题,提高滤波精度,文中将差分演化算法与容积粒子滤波相结合,形成了差分演化容积粒子滤波算法。在粒子进行先验更新时, 使用容积卡尔曼滤波算法融入当前时刻的量测信息并用其来产生重要性密度函数,并且在重采样阶段,用差分演化算法对根据重要性密度函数抽取的采样粒子做优化操作,从而克服粒子滤波存在的粒子退化及贫化问题,提高滤波性能。实验结果表明,和粒子滤波、无迹粒子滤波、容积粒子滤波相比,该算法有着更高的滤波精度和更好的稳定性,并且能够提高雷达机动目标跟踪的精确性。 相似文献
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本文针对雷达杂波抑制中常用的时变级联滤波器,提出了两种实用的设计方法。第一种方法通过时变级联滤波器与时变非级联滤波器的等效来设计时变级联滤波器。该方法可以使时变级联滤波器具有最佳杂波滤波器的效果。第二种方法通过对总的等效滤波器的设计来得到级联滤波器第二级的权系数。分析表明,时变级联滤波器第二级的频率响应很难写出,但可以通过总的等效频率响应来体现。 相似文献
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FIR数字滤波器广泛应用于实时数字信号处理领域.本文介绍了FIR数字滤波器的结构、特点及设计方法,并采用窗函数法设汁了FIR滤波器.利用TMS320VC5509 DSP芯片强大的数字信号处理功能实现了该滤波器.实验表明,此数字滤波器工作稳定,能够满足实时的滤波处理功能. 相似文献
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指数滤波器是一类新构造出来的输出信噪比和目标时延分辨力随指数变化的滤波器,该滤波器在损失一定输出信噪比的前提下可以有效提高目标时延分辨力,从而提高目标时延估计精度,但仅采用单个指数滤波器仍存在输出信噪比和目标时延分辨力均达不到实际需求的情况。在乘积型高阶模糊函数乘积运算的启发下,在指数滤波器的基础上提出了一种新的乘积型指数滤波器,并分析了该乘积型指数滤波器的输出信噪比及目标时延分辨力等性能。仿真实验表明,所提的乘积型指数滤波器在低信噪比情况下可以更有效提高多目标时延估计精度,且算法简单易于实现,适用于背景复杂的多目标参数估计任务。 相似文献