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分析了Link-16数据链信号的特点,描述了数据链的时隙结构、信号时序以及跳频、跳时、信息编码、扩频等实现过程,结合工程实际阐述了信号的产生方法,模拟产生了数据链终端发送的射频信号。 相似文献
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详细地介绍了一种新型的、不需要任何信道信息的空时编码———酉空时编码;并给出了一种简单的、可产生大量的、系统化的酉空时编码的方法。 相似文献
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本文对激光与光学薄膜相互作用的原理做了简要介绍,从激光辐照光学薄膜时产生的光学、热学、声学以及力学效应对薄膜受激光辐照时产生的一系列现象进行分析,综述了国内外对以上效应研究的进展,以及上述研究成果对受高功率激光辐照的光学薄膜设计的指导意义。 相似文献
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程开富 《电子工业专用设备》1989,(1):14-18
热壁LPCVD制备二氧化硅、氮化硅时系统所产生的SiO_2粉尘、氯化铵粉末以及排出的废气对系统中使用的真空泵将产生有害的影响。本文介绍了热壁LPCVD多晶硅膜时操作步骤、工艺参数的选择和操作中应注意的安全问题等。并讨论了LPCVD法制备氮化硅膜时,所用气体SiHCl_3的优缺点以及LPCVD系统中真空泵的防护措施。 相似文献
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文章从磨损现象的产生及类别分析入手,重点阐述了加工零件时,磨损对机床设备造成的影响。如果处理不及时,磨损产生颗粒,从而加剧磨损,严重时能使相互的滑动件中止滑动,产生咬死现象。严重缩短了机床设备的使用寿命。 相似文献
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本文简要介绍了数控机床在加工零件时容易产生的几种误差现象,分析了误差产生的原因,即超程、欠程和传动误差等,并针对这些影响加工精度的因素提出了解决方案。 相似文献
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Sinusoidal interferences are found in ultrasonic signals when we try to characterize a material, as for example interferences coming from PC cards. We are interested in obtaining a robust method that cancels these interferences preserving the waveform of the signal. A Blind Source Separation method to extract these sinusoids is presented in this paper. We will get so many linear mixtures of the backscattering echo of the material and the sinusoids as we need from different pulse responses of the material. 相似文献
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针对相控阵单脉冲雷达体制测角的情况,本文提出了一种降维双和/三差通道自适应同时抑制主、副瓣干扰的算法.该算法利用权值逼近的方法,在非均匀子阵上形成静态和、俯仰差、方位差、双差波束以及指向副瓣干扰方向的和波束,差波束、指向副瓣干扰的和波束作为静态和波束的辅助波束,双差波束作为差波束的辅助波束,根据维纳滤波原理通过对辅助波束的优化加权对消掉和波束中的主副瓣干扰信号及差波束中的主瓣干扰信号,设计出一种新的干扰抑制和测角跟踪算法.所提算法结构简单、测角精度高、能同时抑制主副瓣干扰且鉴角斜率无需修正.仿真实验和性能分析证明了所提算法的有效性和正确性. 相似文献
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TD-SCDMA移动通信系统无线干扰分析 总被引:3,自引:0,他引:3
在简要介绍无线干扰产生的根源的基础上,首先分析了TDD系统中的典型干扰:小区内的干扰、小区间的干扰、TDD系统与FDD系统的干扰等,然后特别研究和总结了建设基于TD-SCDMA标准的3G移动通信系统存在的无线干扰基本情形,主要有:TD-SCDMA技术内的干扰、WCDMA与TD-SCDMA的干扰、cdma2000与TD-SCDMA的干扰、TD-SCDMA与GSM/GPRS的干扰、TD-SCDMA与PHS的干扰等,并从系统工程设计和技术方案设计以及政府频率规划等角度简要指出了降低和消除干扰的方法. 相似文献
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A novel wideband LFM interference suppression method is proposed based on fractional Fourier transform (FRFT) and projection techniques. By using the concentration property of LFM interferences in fractional Fourier domain, the initial frequency, frequency modulation rate and direction-of-arrival (DOA) of LFM interferences are first estimated. Afterwards, the space–time interferences subspace is constructed. In order to suppress wideband LFM interferences, the received signal is projected onto the subspace orthogonal to the interferences subspace when the signals are uncorrelated. Furthermore, considering the scenario when the signals are coherent, according to the properties of oblique projection, LFM interferences are suppressed by projecting the received signal onto the joint signal–noise subspace. Then, the desired signal is extracted by beamforming. Unlike the existing algorithms, the proposed method not only can exactly estimate parameters and directly solve the DOA of LFM interferences but also can construct the interferences subspace with the time-variant steering vector of interferences. Moreover, our method can effectively suppress LFM interferences without reducing the freedom, and significantly improve the performance, even at low signal-to-noise ratio (SNR) or small number of snapshots. Simulation results demonstrate the effectiveness of the proposed method. 相似文献
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An adaptive array utilizing an adaptive spatial averaging technique for multipath environments 总被引:2,自引:0,他引:2
When the interference is coherent with the desired signal, the conventional adaptive arrays working under the guiding principle of output power minimization tend to cancel the desired signal by using the coherent interference. A technique is described which enables the adaptive array to function even under such an environment. The array is divided into subarrays, whose input correlation matrices are adaptively averaged so as to produce a Toeplitz matrix which would be obtained when the interference did not correlate with the desired signal. The averaged matrix is now free from correlation terms between the desired signal and interference, and therefore may be used to derive the optimum weight for the array element just as in the ordinary radio environment of incoherent interference. Numerical examples show that the new adaptive array is highly capable to suppress the coherent interferences as well as incoherent ones. 相似文献
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处理自动化项目中的EMC问题时,通常的做法是找出干扰的原因,隔离或切断传播干扰的途径,并提高系统和设备的自身抗干扰能力。本文从干扰耦合机理以及配电线路电磁干扰试验开始,介绍低压配电系统的各种接地制式,详细分析TN系统产生电磁干扰(EMI)的根本原因及应采取的相应的对策。 相似文献
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An eigenanalysis interference canceler 总被引:4,自引:0,他引:4
Eigenanalysis methods are applied to interference cancellation problems. While with common array processing methods the cancellation is effected by global optimization procedures that include the interferences and the background noise, the proposed technique focuses on the interferences only, resulting in superior cancellation performance. Furthermore, the method achieves full effectiveness even for short observation times, when the number of samples used for processing is of the the order of the number of interferences. Adaptive implementation is obtained with a simple, fast converging algorithm 相似文献