排序方式: 共有17条查询结果,搜索用时 15 毫秒
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DRM(Digital Radio Mondiale)是世界上唯一非专利的数字广播系统,它为30MHz以下频段的长波、中波、短波广播提供了数字化的标准。同步算法和信道估计作为其关键技术对系统性能有着十分重要的影响,文章提出了适用于DRM系统的符号同步算法、整数倍载波频偏估计算法、小数倍载波频偏估计算法以及时频域联合信道估计和均衡算法,并对这些算法进行了仿真分析。 相似文献
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为提高重载组合列车各重联机车无线控制的同步性能,基于800 MHz无线电空间波无线传输模式,建立重载组合列车分布动力机车重联控制无线传输同步性的马尔可夫决策模型,并采用有限阶段向后递归迭代算法进行求解.利用给出的决策模型和算法构建重载组合列车分布动力机车重联无线同步控制系统,并安装于神华线万吨重载组合列车的机车上进行测试.测试结果表明:机车间重联信息无线传输的平均周期仅为2.5s,小于美国GE公司LOCOTROL系统3s的平均周期,能够满足神华线重载组合列车运行的基本要求;采用800 MHz双频点组成双网传输,在无线电波弱场区能克服空间波传输受到干扰的影响,减少延迟时间. 相似文献
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Creating bus timetables with maximal synchronization 总被引:3,自引:0,他引:3
This paper addresses the problem of generating a timetable for a given network of buses so as to maximize their synchronization. It attempts to maximize the number of simultaneous bus arrivals at the connection (transfer) nodes of the network. Transit schedulers, taking into account the satisfaction and convenience of the system's users, appreciate the importance of creating a timetable with maximal synchronization, which enables the transfer of passengers from one route to another with minimum waiting time at the transfer nodes. In this paper, the problem is formulated as a mixed integer linear programming problem, and a heuristic algorithm is developed to solve the problem in polynomial time. The efficiency of this algorithm, compared to optimal solutions, is illustrated through a series of examples. 相似文献
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《海上高频数据通信调制器功能描述》是《海上HF数字和电子邮件无线电通信技术》(青岛远洋船员学院学报2007年第2期)一文的续篇。本文对海上高频数据通信调制器的功能进行了描述,包括海上高频数据通信调制器的组成、设计参数选择、长帧格式、循环冗余校验(CRC)、序列号、短帧格式、扰频器、差分编码、同步序列、快速傅立叶逆变换(IFFT)、周期延长、并行到串行转换、内插器、上变频器等内容。 相似文献
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多机多点牵引道岔同步性研究 总被引:1,自引:0,他引:1
李斌 《铁路通信信号工程技术》2007,4(6):10-12
多点牵引且使用外锁闭的大号码道岔的同步转换要求各牵引点转辙机、外锁闭与道岔尖轨充分协调运动,因此,我们根据道岔各牵引点开口准确地计算相应转辙机动程、外锁闭空动程等相关数据,同时改变转辙机起动顺序,作到六点牵引道岔尖轨基本同步运动。 相似文献
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The relationship between the data to be transmitted and the signal phase in the 16-level quadrature amplitude modulation (16-QAM) constellation is derived. Then a new carrier recovery method based on this relationship is proposed, where both the diagonal and non-diagonal signal points are used for carrier recovery. The analysis and simulation results show that, the proposed method for 16-QAM has a higher acquisition speed than the times-four carrier recovery method, and has a wider acquisition bandwidth and smaller phase errors than the diagonal constellation based carrier recovery method. 相似文献
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In the urban subway transportation system, passengers may have to make at least one transfer traveling from their origin to destination. This paper proposes a timetable synchronization optimization model to optimize passengers’ waiting time while limiting the waiting time equitably over all transfer station in an urban subway network. The model aims to improve the worst transfer by adjusting the departure time, running time, the dwelling time and the headways for all directions in the subway network. In order to facilitate solution, we develop a binary variables substitute method to deal with the binary variables. Genetic algorithm is applied to solve the problem for its practicality and generality. Finally, the suggested model is applied to Beijing urban subway network and several performance indicators are presented to verify the efficiency of suggested model. Results indicate that proposed timetable synchronization optimization model can be used to improve the network performance for transfer passengers significantly. 相似文献