We address the problem of blind carrier frequency-offset (CFO) estimation in quadrature amplitude modulation, phase-shift keying, and pulse amplitude modulation communications systems.We study the performance of a standard CFO estimate, which consists of first raising the received signal to the Mth power, where M is an integer depending on the type and size of the symbol constellation, and then applying the nonlinear least squares (NLLS) estimation approach. At low signal-to noise ratio (SNR), the NLLS method fails to provide an accurate CFO estimate because of the presence of outliers. In this letter, we derive an approximate closed-form expression for the outlier probability. This enables us to predict the mean-square error (MSE) on CFO estimation for all SNR values. For a given SNR, the new results also give insight into the minimum number of samples required in the CFO estimation procedure, in order to ensure that the MSE on estimation is not significantly affected by the outliers.
标签： frequency-offset estimation quadrature amplitude
上传时间： 2014-01-22
上传用户：牛布牛
This paper examines the asymptotic (large sample) performance of a family of non-data aided feedforward (NDA FF) nonlinear least-squares (NLS) type carrier frequency estimators for burst-mode phase shift keying (PSK) modulations transmitted through AWGN and flat Ricean-fading channels. The asymptotic performance of these estimators is established in closed-form expression and compared with the modified Cram`er-Rao bound (MCRB). A best linear unbiased estimator (BLUE), which exhibits the lowest asymptotic variance within the family of NDA FF NLS-type estimators, is also proposed.
标签： performance asymptotic examines non-data
上传时间： 2015-12-30
上传用户：225588
A salient-boundary extraction software package based on the paper: S. Wang, T. Kubota, J. M. Siskind, J. Wang. Salient closed Boundary Extraction with Ratio Contour, IEEE Transactions on Pattern Analysis and Machine Intelligence, 27(4):546-561, 2005
上传时间： 2014-01-23
上传用户：gonuiln
Scotia Airlines is a new budget airline operating between Glasgow Airport and the Western Isles. It operates two 24-seater light passenger aircraft and requires a flight booking system. Because Scotia offers low cost air travel, there is a need to treat each flight as single cost centre and to be able to ascertain, at any moment, the amount of the cash taken for that flight. Reservations and bookings cannot be made until the flight details have been finalised (flight number, departure and arrival airports). A seat on a flight is considered booked when payment as been received for it. When a reservation is confirmed (changed to booked), the passenger name is checked against the original reservation. A flight can be in any of the following states: Available for bookings Checking in Boarding closed
标签： operating Airlines Glasgow Airport
上传时间： 2016-03-25
上传用户：hgy9473
人工智能中的八数码问题：附有详细的注释 我们可以将八数码问题看成移动空格的问题.在不断的移动空格过程当中不断改变棋盘的布局,使之到达目标状态. 用一个open表(本程序采用序栈)的节点,从中选择一个总体代价最小的节点(不妨设为A节点,栈不为空时)是否是目标状态,如果不是则将A节点的有效的儿子节点(不在open表及closed表中出现过,不违反移动规则)插入有序表open表中,并将A节点插入closed表中.然后重复以上操作.
上传时间： 2016-06-04
上传用户：hj_18
This piece of software was written as a replacement and extension for Tripwire. Tripwire is an excellent program in itself but lacks some features and is a closed product.
标签： Tripwire replacement extension software
上传时间： 2014-01-25
上传用户：宋桃子
learning English The following appeared in a memorandum written by the vice president of Nature s Way, a chain of stores selling health food and other health-related products. "Previous experience has shown that our stores are most profitable in areas where residents are highly concerned with leading healthy lives. We should therefore build our next new store in Plainsville, which has many such residents. Plainsville merchants report that sales of running shoes and exercise clothing are at all-time highs. The local health club, which nearly closed five years ago due to lack of business, has more members than ever, and the weight training and aerobics classes are always full. We can even anticipate a new generation of customers: Plainsville s schoolchildren are required to participate in a fitness for life program, which emphasizes the benefits of regular exercise at an early age.
标签： memorandum following president learning
上传时间： 2017-03-05
上传用户：youth25
Introduction Sometimes you may collide with the following problem: a third-party binary component or control embedded into your application displays windows (usually message boxes) that hang your code until they are closed. If you do not have the source code of this binary and one does not have a good API to change one’s bad behaviour programmatically, it can be a real headache using the one. A famous example of such a binary is the WebBrowser control in .NET.
标签： Introduction third-party Sometimes following
上传时间： 2013-12-31
上传用户：pinksun9
The advantages of automation can be exploited in order to solve or to minimize the needs of manual approach. In order to support the development of survey accurate cadastral system, an automatic programming approach will be adopted. Database selection system will conduct several outliers integrity checking, rebuild cadastral spatial topology (cadastral lot) and make selfcorrection procedures based on cadastral survey concepts and mathematical model respective to the cadastral lots selected. This is to ensure that all cadastral lots are kept in a closed polygon and provide accurate and "clean" cadastral information.. This system was developed in windows environment.
标签： advantages automation exploited minimize
上传时间： 2017-04-28
上传用户：520
Servomotors are available as AC or DC motors. Early servomotors were generally DC motors because the only type of control for large currents was through SCRs for many years. As transistors became capable of controlling larger currents and switching the large currents at higher frequencies, the AC servomotor became used more often. Early servomotors were specifically designed for servo amplifiers. Today a class of motors is designed for applica-tions that may use a servo amplifier or a variable-frequency controller, which means that a motor may be used in a servo system in one application, and used in a variable-frequency drive in another application. Some companies also call any closed-loop system that does not use a stepper motor a servo system, so it is possible for a simple AC induction motor that is connected to a velocity controller to be called a servomotor.
标签： motors Servomotors servomotors available
上传时间： 2014-08-09
上传用户：源码3
