Use the fast Fourier transform function fft to analyse following signal. Plot the original signal, and the magnitude of its spectrum linearly and logarithmically. Apply Hamming window to reduce the leakage. . The hamming window can be coded in Matlab as for n=1:N hamming(n)=0.54+0.46*cos((2*n-N+1)*pi/N); end; Where N is the data length in the FFT.
标签： matlab fft
上传时间： 2015-11-23
上传用户：石灰岩123
Computational models are commonly used in engineering design and scientific discovery activities for simulating complex physical systems in disciplines such as fluid mechanics, structural dynamics, heat transfer, nonlinear structural mechanics, shock physics, and many others. These simulators can be an enormous aid to engineers who want to develop an understanding and/or predictive capability for complex behaviors typically observed in the corresponding physical systems. Simulators often serve as virtual prototypes, Where a set of predefined system parameters, such as size or location dimensions and material properties, are adjusted to improve the performance of a system, as defined by one or more system performance objectives. Such optimization or tuning of the virtual prototype requires executing the simulator, evaluating performance objective(s), and adjusting the system parameters in an iterative, automated, and directed way. System performance objectives can be formulated, for example, to minimize weight, cost, or defects; to limit a critical temperature, stress, or vibration response; or to maximize performance, reliability, throughput, agility, or design robustness. In addition, one would often like to design computer experiments, run parameter studies, or perform uncertainty quantification (UQ). These approaches reveal how system performance changes as a design or uncertain input variable changes. Sampling methods are often used in uncertainty quantification to calculate a distribution on system performance measures, and to understand which uncertain inputs contribute most to the variance of the outputs. A primary goal for Dakota development is to provide engineers and other disciplinary scientists with a systematic and rapid means to obtain improved or optimal designs or understand sensitivity or uncertainty using simulationbased models. These capabilities generally lead to improved designs and system performance in earlier design stages, alleviating dependence on physical prototypes and testing, shortening design cycles, and reducing product development costs. In addition to providing this practical environment for answering system performance questions, the Dakota toolkit provides an extensible platform for the research and rapid prototyping of customized methods and meta-algorithms
标签： Optimization and Uncertainty Quantification
上传时间： 2016-04-08
上传用户：huhu123456
最近在学习Oracle，对测试人员而言必须掌握两种语言：第一种是DML，数据操纵语言 (Data Manipulation Language) 是SQL语言中，负责对数据库对象运行数据访问工作的指令集，以INSERT、UPDATE、DELETE三种指令为核心，分别代表插入、更新与删除。第二种是：DQL，数据查询语言 (Data Query Language) 是SQL语言中，负责进行数据查询而不会对数据本身进行修改的语句，这是最基本的SQL语句。核心指令为SELECT，以及一些辅助指令，如FROM、Where等，FROM：表示来源，可以搭配JOIN做链接查询； Where：过滤条件；GROUP BY：在使用聚合函数时用到，如SUM,COUNT,MAX,AVG；HAVING：对聚合结果进行筛选，这是和Where的不同点；ORDER BY：排序。
标签： oracle 基础 资料
上传时间： 2016-09-15
上传用户：天涯云海
transimpedance linearization circuitry. This allows it to drive video loads with excellent differential gain and phase perfor mance on only 50 mW of power. The AD8001 is a current feedback amplifier and features gain flatness of 0.1 dB to 100 MHz while offering differential gain and phase error of 0.01% and 0.025°. This makes the AD8001 ideal for professional video electronics such as cameras and video switchers. Additionally, the AD8001’s low distortion and fast settling make it ideal for buffer high-speed A-to-D converters. The AD8001 offers low power of 5.5 mA max (VS = ±5 V) and can run on a single +12 V power supply, while being capable of delivering over 70 mA of load current. These features make this amplifier ideal for portable and battery-powered applications Where size and power are critical. The outstanding bandwidth of 800 MHz along with 1200 V/µs of slew rate make the AD8001 useful in many general purpose high-speed applications Where dual power supplies of up to ±6 V and single supplies from 6 V to 12 V are needed. The AD8001 is available in the industrial temperature range of –40°C to +85°C.
上传时间： 2020-04-21
上传用户：su1254
The world population is continuously growing and reached a significant evolution of the society, Where the number of people living in cities surpassed the number of people in rural areas.
标签： Building Future Cities Smart
上传时间： 2020-05-23
上传用户：shancjb
The rapid growth in mobile communications has led to an increasing demand for wide- band high data rate communications services. In recent years, Distributed Antenna Systems (DAS) has emerged as a promising candidate for future (beyond 3G or 4G) mobile communications, as illustrated by projects such as FRAMES and FuTURE. The architecture of DAS inherits and develops the concepts of pico- or micro-cell systems, Where multiple distributed antennas or access points (AP) are connected to and con- trolled by a central unit.
标签： Distributed Antenna Systems
上传时间： 2020-05-27
上传用户：shancjb
Multiuser multiple-input-multiple-output (MU- MIMO) systems are known to be hindered by dimensionality loss due to channel state information (CSI) acquisition overhead. In this paper, we investigate user-scheduling in MU-MIMO systems on account of CSI acquisition overhead, Where a base station dynamically acquires user channels to avoid choking the system with CSI overhead.
标签： Acquisition Dynamic Channel
上传时间： 2020-05-27
上传用户：shancjb
We were on the lookout for ice. I was in a 32 foot sailing yacht with writer and explorer Tristan Gooley, undertaking a double-handed sail from Scotland through the Faroes up to 66 33 45.7 N and the midnight sun. Now sailing out of the Arctic Circle we were approaching Iceland from the north, heading for the Denmark Straits, Where ice flowed south. The Admiralty Pilot warned of bergs but the ice charts we had sailed with were over a week old. We needed an update.
标签： Interference Analysis
上传时间： 2020-05-27
上传用户：shancjb
Mobile telephone service (MTS) is a type of service Where mobile radio tele- phones connect people to the public switched telephone system (PSTN), to other mobile telephones or to other communication systems (such as to the Internet).
标签： Introduction Telephone Systems Mobile to
上传时间： 2020-05-27
上传用户：shancjb
In order to improve the spectral efficiency in wireless communications, multiple antennas are employed at both transmitter and receiver sides, Where the resulting system is referred to as the multiple-input multiple-output (MIMO) system. In MIMO systems, it is usually requiredto detect signals jointly as multiple signals are transmitted through multiple signal paths between the transmitter and the receiver. This joint detection becomes the MIMO detection.
标签： Complexity Detection MIMO Low
上传时间： 2020-05-27
上传用户：shancjb
