共查询到20条相似文献,搜索用时 203 毫秒
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《电子技术与软件工程》2016,(17)
分析一起在发电机启动过程中定子三次谐波接地保护动作事件,根据保护原理,结合现场设备实际情况及保护动作特性,详细分析报警原因,阐述了处理过程及分析,以防止定子三次谐波接地保护动作,避免此类事件发生。 相似文献
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通过研究,将发电机中心点接地方式及定子接地保护策略进行了分析,核心目的是通过专业技术的优化,促进发电机技术的创新发展,实现电力企业的稳定运行. 相似文献
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考虑到传统的隐式空间映射算法(ISM)在参数提取中会出现收敛速度慢甚至假收敛的情况,将改进的蛙跳算法用于隐式空间映射的参数提取,可有效改善参数提取过程中算法的不收敛性。通过改进参数提取中精确和粗糙模型的映射关系,可以明显减少迭代次数,并用于优化设计一个可工作在无线局域网(WLAN)的微带双频带滤波器。滤波器的中心频率分别为2.45GHz和5.25GHz,滤波器经过3次迭代后达到设计要求,验证了算法的可行性和有效性。 相似文献
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文章介绍了一种数字信号处理器 (DSP)程控自适应滤波器的设计 ,并将它应用于汽车防撞雷达有用双频信号提取的实例中 相似文献
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基于横向滤波器耦合结构,采用支节加载双模谐振器,设计了中心频率位于1.57 GHz(GPS应用)与2.4GHz(WLAN应用)的双频微带滤波器。由短路支节加载双模谐振器形成第一个通带,开路支节加载双模谐振器形成第二个通带,两个谐振器被输入/输出馈线隔离,每个通带的中心频率与带宽可以单独调节。测试结果表明:两个通带内的最小插损分别为2.18,1.35 dB,3 dB带宽分别为5.2%,6.8%,回波损耗均小于16 dB,三个传输零点分别位于1.28,2.08,2.71 GHz处。该滤波器具有尺寸小、带外选择性好等优点。 相似文献
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《电子元件与材料》2016,(12):57-60
将粒子群算法(Particle Swarm Optimization,PSO)用在隐式空间映射(Implicit Space Mapping,ISM)的参数提取中,可以有效改善参数提取过程中算法的不收敛性。首次在参数提取中引入PSO,主要的研究内容是改进了ISM算法。通过改进ISM算法中粗糙模型(Coarse Model,CM)与精细模型(Fine Model,FM)之间的参数映射,可以明显减少迭代次数。以一个双模滤波器为例,利用粒子群ISM算法设计了一个可以工作在无线局域网(WLAN)频段的微带双频带滤波器,中心频率分别是2.45 GHz和5.25 GHz。滤波器经过3次迭代并进行微调后达到了设计指标。由此可见,引入PSO之后显著地减少了在FM中的仿真次数,有效地提高了滤波器的设计效率。 相似文献
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电厂作为电力系统的结点,研究接地保护与防腐意义深远。本文首先研究了接地体保护设计与接地体防腐相关的话题,指出了具体的防腐要求,然后探究了电厂配电设计的接地保护方式实施,最后提出了过程中的应该注意的事项。 相似文献
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提出了一种新型的基于缺陷地结构的双频带带通微带滤波器.缺陷地结构采用双模开口谐振环形式, 并使用不同组合方式的双模开口谐振环产生两个通带.滤波器的两个工作中心频率分别为3.5 GHz和5.8 GHz, 其中第一个频带涵盖了所有全球微波互联接入的应用频段, 第二个频带可以应用于雷达设备.为了进一步证实这款滤波器的性能, 基于Roggers RT5880板材制作了滤波器实物, 整体滤波器的大小仅为20 mm×20 mm, 测量数据和仿真结果吻合较好, 并且有两个传输零点, 可以满足工程上的需要. 相似文献
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A.A. Omar O.H. Abu Safia M.C. Scardelletti 《International Journal of Electronics》2013,100(3):311-322
Several recent applications in communications require filters that can operate in two or more frequency bands. The aim of this article is to exploit the advantages of coplanar waveguides (CPWs) to design a dual-band bandpass coplanar waveguide filter (DBBPF). Starting from the prototype of a two pole Chebyshev low pass filter, two frequency transformations are applied to generate the DBBPF's lumped equivalent circuit. These circuits are then implemented using compact CPW series-connected resonators patterned in the centre conductor. The designed filter operates at the two frequency bands centred at 1.7 GHz and 2.7 GHz. Measured results are obtained and compared to HFSS-simulated results with very good agreement. 相似文献
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A compact dual-band switchable bandpass filter is designed using two centrally-loaded open-loop resonators and six pin blocks. The pin diodes are loaded at the zero-voltage points of odd and even modes along the microstrip resonators, such that the two passbands operating at odd and even modes can be individually switched on or off. The isolations for the two passbands are greater than 20 dB. 相似文献
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This article presents a compact microstrip dual-band bandstop filter (BSF), in which one λg/4 defected ground structure (DGS) pair is utilised to realise one stopband while two stepped impedance resonators (SIRs) help obtain another stopband and suppress the spurious harmonics. The design strategies and the equivalent circuits are introduced in detail. The measured results indicate 43.8% and 18.7% fractional bandwidth in the two stopbands (2.4 GHZ and 5.2 GHz) respectively, and the return loss is greater than 15 dB in the whole passband. In addition, size reduction can be conveniently achieved by adjusting the length of the SIRs and DGS. 相似文献
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Poikonen J. Paasio A. 《IEEE transactions on circuits and systems. I, Regular papers》2004,51(5):974-987
Order statistic filtering, the generalization of which is ranked order filtering, is needed for many image-processing functions including median filtering and mathematical morphology. Combining order statistic functionality with the parallel operation and local connectivity of array processing approaches such as the cellular nonlinear network model, has the potential for very high performance in image processing. This paper examines the implementation of programmable ranked order extraction with a very compact hardware realization of an analog current-mode ranked order filter. The considerable savings in the required circuit area, compared to other circuits, make it possible to use the structure as a building block in a massively parallel signal processing array. The operation of the circuit is analyzed in detail with the help of simulations and measurement results obtained from a test chip manufactured in a 0.18-/spl mu/m standard digital CMOS technology are also presented. The simulations and measurement results verify the correct operation of the circuit and show that it is very suitable for inclusion in every cell of a large parallel processor array. This makes many grayscale processing functions available with truly parallel operation and therefore very high performance. 相似文献
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A novel microstrip tunable dual-band bandpass filter with high attenuation level in the upper stopband region is presented. The proposed structure comprises of T-shaped resonators and the coupled microstrip feeding lines. To reach a compact size, the feeding lines are bended. By altering the physical lengths, the characteristics of BPF can easily tune. So, the operational frequencies of the filter can be adjusted and has been fixed to 2.1 GHz and 2.63 GHz, which are applicative for 3G and 4G systems. The insertion-losses of the first and second pass-bands are only 0.68 dB and 1.08 dB, respectively. The undesired harmonics in the upper stopband, with an excellent attenuation level of −38 dB, are rejected up to 6.65 GHz. The results exhibit high return loss of 19.3 dB and 30.7 dB in the first and second pass-bands. The proposed circuit has been fabricated and tested that the obtained results are well close to the simulations results. The total size of the designed circuit is only 16.4 × 13.4 mm2. 相似文献
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《中国邮电高校学报(英文版)》2014,21(6):94-99
This paper studies the behaviors of power amplifier (PA) driven by a single-carrier continuous wave (CW) signal and a two-carrier CW signal both in theory and simulation, and explains why the traditional dual-band PA failed to perform satisfactory results when a two-carrier CW signal is applied to, called concurrently. Besides that, an evaluation standard of concurrent dual-band PA was presented to value its performance. Solution was given with design and fabrication of a concurrent 1.85 GHz/2.65 GHz class F PA, employing a 10W GaN HEMT device from Cree, CGH40010, whose measurement shows the saturated output power is 40.6 dBm and 40.8dBm with drain efficiencies (DE) of 77.4% and 75.3% at 1.85 GHz and 2.65 GHz, respectively. On the other hand, we see that the peak DE achieves 59.7% with an output power of 39.9 dBm in concurrent mode, which follows up with the standard. 相似文献
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针对民用无人机(UAV)对军事目标等重点要害部位的安全威胁问题需要无人机干扰天线的现状,设计实现了一种改进的双频双馈八木天线。分析了民用无人机特点,提出干扰天线技术指标,对主要形状尺寸进行计算;通过HFSS仿真软件仿真得到双频双馈八木天线的具体参数;最后实际制作了该型天线并进行实测。仿真和实测结果表明,设计的天线具有增益高、质量轻、小型化的特点,能够满足无人机干扰天线的要求。 相似文献