共查询到19条相似文献,搜索用时 156 毫秒
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多波束搜索雷达采用多个同时接收波束对每一个发射波束的照射空域进行覆盖,其波束形状损耗计算和影响与单波束搜索模式存在差异。文中研究了多波束搜索雷达中波束形状损耗对系统检测性能的影响,推导了通用的计算方法,并利用仿真方法研究了不同系统参数配置下的检测性能。由仿真结果可知,波束形状损耗一般随同时接收多波束数目的增加而减小。 相似文献
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该文将单相位中心多波束(SPCMB)星载SAR系统与脉内波束指向相结合,有效地解决了传统SPCMB- SAR系统方位模糊较大的问题。该文推导了接收端方位向、距离向及2维联合数字波束形成(DBF)的处理方法,并归纳出先方位向DBF后距离向DBF,先距离向DBF后方位向DBF,以及2维DBF 3种处理流程。同时分析了该系统的主要系统参数,对比了3种处理流程的数据率和计算复杂度。仿真验证了3种处理方法的有效性,并通过模糊度分析证明采用该系统能降低方位模糊和距离模糊,有效实现高分辨率宽测绘带成像。 相似文献
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数字波束形成技术在阵列信号处理中应用愈来愈广泛,采用数字波束形成技术实现多波束具有很高的灵活性。论文对数字式多波束形成系统进行了较详细的分析,对工程设计中波束宽度、影响波束合成效率的主要因素进行了仿真分析,对系统的幅相校准方法进行了讨论。文中给出设计完成后的系统硬件及说明。 相似文献
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研究了基于注频锁相振荡器阵列的非线性有源天线阵多波束拓扑结构模型,详细分析了一维线阵、二维面阵多波束相位分布的控制方法并完成了一维线阵、二维面阵的相位分布仿真和方向图仿真,验证了该方法的有效性。最后,完成了多波束性能的分析。 相似文献
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面向新一代多功能相控阵雷达对天线发射多波束技术的急需,本文在分析了雷达发射多波束特点的基础上,讨论了发射多波束技术在对地多功能监视雷达、防空反导多功能雷达和侦干探通多功能系统等领域的典型应用;梳理并总结了雷达发射多波束技术的研究历程和发展趋势;提出了单元级数字阵列雷达发射多波束的技术架构和实现方式,分析研究了单元级数字阵列多功能雷达实现发射多波束所涉及的波束带宽积提升、多路相位同步、分布式相参频率源、高效率实现和雷达资源的管理和控制等关键技术,为单元级数字阵列发射多波束的深入研究提供了技术路径。 相似文献
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构用共面多光束干涉在光折变晶体中形成了对比度较大的一维、二维周期性晶格微结构。理论和实验对比研究了共面双光束和多光束在光折变晶体中会聚相干形成周期微结构的分布规律和影响因素。在相干理论的基础上,建立了具有普适性的共面多光束相干数学模型,数值模拟了n(n=1,2,3,4,5,6)束共面激光相干光场的光强分布规律。实验结果表明,干涉光场图案分布同数值模拟相吻合。实验中进一步讨论了相干系统各参数变化对干涉效果的影响,并通过全息记录在铁电铌酸锂晶体中构造出了同多光束干涉场光强分布对应的光子晶格微结构。 相似文献
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提出了利用真对数放大器扩展数字接收机动态范围的方法.对真对数放大器的双音互调特性及其DBF应用进行仿真验证.结果表明,真对数放大器在保留输入信号幅度、相位信息等特性的情况下,把较大的输入功率范围压缩成较小的功率范围,从而实现了比采用线性放大器的接收机更大的动态范围.但是,其较强的非线性效应影响了它在宽带数字接收机中的广泛应用. 相似文献
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K. G. Johannsen J. Hintze 《International Journal of Satellite Communications and Networking》1991,9(3):155-165
In the recent development of phased array/distributed amplifier systems for application to mobile satellite or thin route communication systems, the intermodulation (IM) generated by the element amplifiers is spatially dispersed in such a way that some of the IM radiated energy falls outside the intended beam area. In addition, some of the IM falling inside the beam area has frequencies different from the carriers intended for that area. It is known that for fixed beam systems with frequency reuse, an average IM noise reduction of several dB can be realized. In the specific case under investigation, of four beams, nine frequencies and 12 carriers (1-33 frequency reuse factor), an IM improvement of about 2-0 dB is realized. The improvement in carrier-to-IM-noise ratio can be applied to increase system capacity, or for given capacity it can be used to reduce RF power amplifier back-off, which can be translated into a reduction of spacecraft prime power requirement. The considerable advantage gained from the multiple beam distributed amplifier approach makes it worthwhile to explore the workings of such a system and other benefits it may offer. One of the benefits is a common RF power pool for all carriers and beams, and the other is the spatial dispersion of intermodulation (IM). A satellite multiple beam pattern and the spatial dispersion of IM products are shown in Figure 1. 相似文献
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WUKai-hua HUANGZuo-hua YANKuang 《半导体光子学与技术》2005,11(1):16-19
Self scanning photodiode array (SSPA) is a kind of solid state imaging sensor. The signal processing method using a special sector SSPA was investigated. Based on the principle and characteristics of SSPA, a signal acquisition and processing method controlled by computer was introduced. The amplification of weak signal, the matching of time sequence, the fast peak holding with low leakage, the high speed A/D conversion and nonlinear correction were discussed. This method can acquire the peak signal of every ring of sector SSPA with high accuracy and in real time. It can be used to detect the distribution of space light energy. 相似文献
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Emrah Öncü Rasit Tutgun Emre Aktas 《International Journal of Satellite Communications and Networking》2023,41(6):589-598
Conventional solid-state power amplifier (SSPA) design approach isolates radio frequency (RF) design from communication theory. In this paper, a unified SSPA design approach is proposed, which optimizes SSPA parameters (bias voltage and input RF signal power) to minimize total DC power consumption while satisfying received SNR constraint specified by the link budget. The effect of SSPA nonlinearity is quantified by the error vector magnitude measured at its output and the corresponding received SNR degradation is analyzed. Using the quantitative metrics for received SNR, it is possible to evaluate highly nonlinear SSPA classes such as Class-B or deep-Class AB, which are normally not considered in conventional SSPA design approach to be used in satellite communication applications. 相似文献
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《Microwave Theory and Techniques》1985,33(12):1395-1403
A third-order analysis for accurately predicting large-signal power and intermodulation distortion performance for GaAs MESFET amplifiers is presented. The analysis is carried out for both single- and two-tone input signals using the Volterra series representation and is based only on small-signal measurements. Simple expressions for the nonlinear power gain frequency response, the output power, the gain compression factor, and the third-order intermodulation (IM/sub 3/) power are presented. The major sources of gain compression and intermodulation distortion are identified. Based on the developed nonlinear analysis in conjunction with the device nonlinear model, a systematic procedure for designing a MESFET amplifier under large-signal conditions for optimum output power and IM/sub 3/ performance is proposed. The method utilizes out of band computed matching compensation through a nonlinear model of the amplifier. The accuracy of the device large-signal and IM/sub 3/ distortion characterization and the practicability of the proposed method are illustrated through comparison between measured and predicted results. 相似文献
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A percentage linearization (PL) and a percentage linearization area (PLA) are defined and proposed as two new measures of the degree of AM-to-AM linearization, achieved by a linearization scheme, of the saturating region of nonlinear high power amplifiers (HPAs). The measures are based on defining a HPA saturation power point which is very close to the asymptotic output saturation power (AOSP) line. Here the point where the first derivative of the AM-to-AM dB power characteristic drops to 0.1 is so defined. Employing the passage through a typical pseudomorphic high electron mobility transistor solid-state power amplifier (PHEMT SSPA) of an UWC-136 8-PSK signal, as a test signal, an introductory insight into the usefulness of these linearization measures is presented. 相似文献