共查询到20条相似文献,搜索用时 62 毫秒
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结合GSM全向基站的传播模型校正实例,简要介绍了无线传播模型的种类和校正原理,以及无线传播模型校正的基本流程。 相似文献
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从经典的SPM模型及校正流程出发,针对某丘陵地貌城市的2.6 GHz SPM模型校正,进一步结合该城市前期的TD-SCDMA 2 GHz SPM模型校正结果,经过仿真分析和对比,得出了丘陵地貌下的F/D频段传播路径损耗差异,可为有效指导丘陵地貌下的传播模型校正提供参考。 相似文献
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3G无线传播模型校正 总被引:5,自引:0,他引:5
介绍了3G模型校正中CW测试方法和原理、模型校正的方法、模型校正的最小二乘法原理及评判模型正确与否的标准,最后给出了一个传播模型校正实例。 相似文献
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在3G无线网络规划时,为了尽可能减少误差,提高无线覆盖预测和干扰预测的精度,需要对采用的传播模型进行参数校正。本文从传播模型校正原理和方法入手,结合测试环境,对A市市区WCDMA无线传播模型进行校正,并对校正结果进行验证。 相似文献
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本文简要介绍了移动通信中传播模型的概念和几种常用的传播模型,论述了模型校正的必要性,并详细介绍了模型校正的步骤,同时对模型校正中可能出现的误差进行了分析. 相似文献
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WCDMA无线传播模型测试校正 总被引:1,自引:0,他引:1
无线传播模型测试与校正是移动通信网络建设的重要步骤.它为网络规划提供覆盖预测的基础。WCDMA系统的工作频段在2GHz左右.与第二代移动通信系统相差大,因此有必要在WCDMA的工作频段内开展传播模型测试与校正工作。 相似文献
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基于FLAASH和6S模型的Spot 5大气校正比较研究 总被引:1,自引:0,他引:1
采用基于大气辐射理论的FLAASH和6S模型,对Spot5遥感影像进行了大气校正,通过比较校正前后地物光谱曲线和NDVI分析两种类型的实际校正效果,结果表明,FLAASH模型能较好地消除了大气影响,对Spot5遥感影像有更好的校正作用。 相似文献
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《Microwave Theory and Techniques》2009,57(2):383-394
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分析了2种典型的传播模型:Okumura—Hata模型和COST231-Hata模型,重点叙述了数据采集和数据处理、传播模型校正的原理、校正的具体过程及其校正准则。 相似文献
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为了研究光栅调谐外腔半导体激光器的调谐特性和双稳特性之间的关系,采用建立H参量简化模型、以载流子密度表征阈值特性的方法,得到了以H参量表达的调谐范围解析式,对反共振所需剩余反射率的上限进行了理论分析,数值模拟了激光出射端反射系数、剩余反射率对调谐范围和双稳环环宽的影响,得到了环宽最大值的位置。结果表明,H参量简化模型能够阐明光栅调谐外腔半导体激光器的调谐特性与双稳特性的关系。 相似文献
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This paper describes a method for computer-controlled tuning of waveguide filters. The tuning algorithm is based on approximate filter network models, which take into account the effects of input/output coupling. Based on measurements of an initial filter design, the approximate network model is then corrected by optimizing the element values such that they minimize the mean square error between the measured and simulated response. The sensitivities of the tuning screws are determined directly from the sensitivities of the element values. Filter tuning is accomplished by gradient optimization of the corrected computer model rather than its physical realization. Only as a final step are the tuning screws of the physical model turned to the position determined by the optimization process 相似文献
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Sequential tuning of microwave filters using adaptive models and parameter extraction 总被引:1,自引:0,他引:1
This paper describes a sequential procedure for computer-aided tuning and diagnosis of multiple-coupled resonator filters. The method is based on a sequential parameter estimation and a systematic tuning procedure and employs three different filter models. A detuned model represents the initial status of the filter after a well-defined detuning procedure. The target filter is described by an ideal model, whereas the actual state of the filter at each tuning step is represented by a coarse adaptive model. The goal of the procedure is the convergence of the coarse model to the ideal model and will be obtained by systematically centering resonant frequencies and coupling coefficients. Practical examples comprising low- and high-degree filters confirm the effectiveness of the proposed approach in both tuning and fault diagnosis. 相似文献
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《Microwave Theory and Techniques》1974,22(5):554-556
An analytic model for electronic tuning of an X-band waveguide transferred-electron oscillator is presented. The oscillator is electronically tunable by a varactor, and mechanically tunable by movement of a short circuit. The model is used to predict oscillation frequency, maximum electronic tuning range, and electronic tuning versus varactor bias voltage. Two different methods, the "zero reactance theory" and the Slater perturbation theory, are used to calculate the electronic tuning. The results of these calculations are compared to experimental results for two different oscillator configurations. 相似文献
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A model and analysis are presented for tuning of a resonant inverter. The model uses linearised phase-frequency characteristic of a tank load near the resonant frequency. To demonstrate the validation of the model, a low-power prototype was implemented using a CD4046 phase-locked loop chip in the tuning circuit 相似文献
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Calvez S. Rejeaunier X. Mollier P. Goedgebuer J.-P. Rhodes W.T. 《Lightwave Technology, Journal of》2001,19(6):893-898
We propose a new method for tuning an Er3+-doped continuous-wave fiber-ring laser. We present a novel numerical model and confirm the model with experimental results. The numerical model relies on the implementation of the analytical solution of signal propagation over small (elemental) segments of amplifier fiber rather than using the usual Runge-Kutta algorithm. The validity of the model is verified by the good agreement between computer results and experimental data. Experiments demonstrating a 11.2-nm wavelength tuning range have been conducted using an electrooptic intracavity filter composed of two cascaded unbalanced Mach-Zehnder interferometers (MZIs) integrated in lithium niobate. The numerical analysis shows that the tuning range obtained is limited by the combination of gain shape and filter characteristics. Increased tuning range can be obtained by decreasing losses or by using a more selective filter 相似文献