后脉冲概率的统计测量

在对单光子探测过程中后脉冲现象进行理论分析的基础上,通过实验对后脉冲概率进行了统计测量,这种方法与其它方法的不同之处在于不需要更多的实验仪器,而测量得到的实验结果与其他实验方法的不同。这里对实验条件的确定进行了分析和讨论。     

基于布里渊散射的外差检测式光纤传感系统性能分析

在对基于布里渊散射的分布式传感原理分析的基础上,给出了一种外差检测式BOTDR传感实验系统,对其性能进行了详细地分析.并在理论推导的基础上,与实验结果进行了对比,实验结果验证了理论分析的正确性.     

基于LabVIEW的自动控制原理虚拟实验系统

根据"自动控制原理"课程实验教学在高校实验实践中遇到的困难和实验教学改革的需要,本文提出了建立基于LabVIEW的自动控制虚拟实验系统方案.文中分析了目前常见的虚拟实验系统的优缺点,相应的应用LabVIEW编程语言实现了包含"自动控制原理"课程常见实验的虚拟实验系统,并提出了进行硬件实验扩充的设想.最后,利用Matlab语言编程进行对比分析,进行正确性验证.     

“电子技术”课程虚拟实验的应用

本文分析了“电子技术”课程实验教学的不足现状,阐述了“电子技术”课程实物实验与虚拟实验整合的必要性.我们在对电子技术实验项目类型进行分析基础上,针对不同实验类型进行虚拟实验的应用,并给出虚拟实验的案例.“电子技术”课程虚拟实验的应用研究结论为虚拟实验可以和实物实验实现理想整合,共同实现课程教学目标.     

音频频谱分析仪仿真实验

频谱分析仪是一种用来对被测信号进行频率及频谱分析的重要测量仪器,广泛应用于电声测量,音频制作,信号分析乃至振动测试等领域。本设计介绍了MATLAB仿真环境,之后对数字仿真进行了探讨,最后重点介绍了音频频谱分析仪仿真实验的详细设计方法,实验过程和结果,井对实验结果进行了分析。     

石英晶振加力方位角的ANSYS分析与实验检验

通过ANSYS8.0对几种石英晶振在加力方位角改变时的应力分布进行了分析计算,并通过实验对石英晶振频率变化和加力方位角关系进行了验证。实验表明,ANSYS8.0分析结果曲线和实验曲线几乎一致。利用此法分析了石英谐振器力敏特性简单、实用、高效。     

一种宽带D类射频功率放大模块设计

介绍了一种宽带D类射频放大模块设计实验过程。给出了放大器的设计原理图,并对放大器设计中的关键参数计算、关键器件选取进行了分析。对放大器模块设计中关键电路进行了实验仿真分析,最后给出放大模块的实验测试结果。     

基于OLAP的电子对抗作战部署要素分析方法

为了分析多个实验要素(实验因子)与实验结果之间的因果关系,从而探索电子对抗作战部署问题规律,对基于联机分析处理技术(OLAP)的实验要素分析方法进行研究.基于实验要素分析的几类需求,提出基于OLAP的探索分析方法,并进行了详细论述说明,然后通过将该方法应用于解决电子对抗作战部署的要素分析,展示具体运用方法.     

功率因数提高的Multisim仿真和实验分析

为了清楚直观地了解如何提高负载的功率因数,将理论分析、仿真分析以及实验分析三者进行有机的结合。在理论分析的基础上,利用Multisim仿真软件对感性负载电路功率因数的提高进行了仿真分析,并设计了实验电路对理论分析以及仿真分析的结果进行验证。     

硅／硅直接键合界面的AES分析

本文应用AES分析的方法,对硅/硅直接键合界面进行了研究,给出了实验结果,并对实验结果进行了分析论证。     

SS/FDMA router for flexible satellite communications networks

The subchannel switched frequency-division multiple-access (SS/FDMA) system improve the routing flexibility of transponder banks in channelized multibeam satellites. This system can efficiently be utilised to construct a VSAT (very small aperture terminal) network and/or a business satellite communications network using small aperture terminals. The authors address the application of the SS/FDMA system to such networks. A proof-of-concept (POC) model of SS/FDMA onboard equipment called the SS/FDMA router is described in terms of its configuration and measured electrical performance. Results of transmission experiments using the POC model as well as computer simulations are presented. In addition, a redundant SS/FDMA router configuration is proposed, and its reliability is calculated for a 15-year satellite mission time. Finally, estimated values of volume, mass, and DC power consumption of the redundant SS/FDMA router are presented     

Spread SCPC/FDMA,spread TDMA/FDMA and SSMA/FDMA transmission through A non-linear satellite channel with an earth-station off-axis emission constraint

This paper analyses and compares possible access schemes to be used in satellite networks with a large number of small earth-stations. Basically, frequency division (FDMA), time division (TDMA), and spread spectrum multiple access (SSMA) are considered. For TDMA, one single carrier originated in one particular earth-station is transmitted in each sub-band and therefore a single-channel-per-carrier system results (SCPC/FDMA). For TDMA and SSMA, it is assumed that groups of earth-stations using either of these access schemes share the full available band in FDMA. The corresponding systems are thus TDMA/FDMA and SSMA/FDMA. Moreover, for SCPC/FDMA and TDMA/FDMA individual carriers may be spread to the extent that the available bandwidth is always fully occupied. Spectral efficiencies for these three access modes (Spread SCPC/FDMA, Spread TDMA/FDMA and SSMA/FDMA) are computed and compared for transmission through a non-linear satellite channel and optimum operating points for the non-linear amplifier are also determined. Comparisons are also performed for the situation in which transmitting earth-stations are bounded to obey an off-axis emission constraint.     

Reducing PAPR of SC‐FDMA Signals through Simple Amplitude Predistortion

A novel peak‐to‐average power ratio (PAPR) reduction method is proposed for single‐carrier frequency‐division multiple access (SC‐FDMA) signals. The proposed method deliberately distorts the amplitude values of a few of the complex modulated symbols that cause peaks beyond a predetermined threshold in the samples of the output signal. The method then marks the location indices of the distorted symbols by using a pilot block at the transmitter without transmitting side information. At the receiver, the method is then able to recover the distorted amplitude values through the marked location indices. Computer simulation results show that when compared to conventional SC‐FDMA signals, the proposed scheme can effectively reduce the PAPR of SC‐FDMA signals with asymptotically consistent bit error rate (BER) performance.     

ICI problem and compensation in MIMO SC‐FDMA system with SC‐SFBC scheme

In this paper, we address the ICI (intercarrier interference) problem and compensation in MIMO (multiple input multiple output) SC‐FDMA (single carrier frequency division multiple access) system that exploits SC‐SFBC (single carrier‐space frequency block coding) scheme. Recently, SC‐FDMA technique has received more attention due to the low PAPR (peak to average power ratio) property. However, SC‐FDMA system is sensitive to phase noise and CFO (carrier frequency offset) which is unavoidable in wireless communication systems. Phase noise and CFO introduce CPE (common phase error) as well as ICI into the received signal and seriously degrade the system performance. Therefore, analysis and suppression of these interferences are of great importance. In this paper, we analyze the interferences in MIMO SC‐FDMA system with SC‐SFBC. Then a new ICI estimation and suppression method is proposed to suppress the interferences. Instead of directly estimating the CFO and phase noise, which is pretty difficult and complex, this algorithm exploits block‐type pilots, which is a common pilot pattern in wireless communication systems, such as LTE standard, to estimate the interferences. After that the interferences are suppressed by the inverse matrix method. Simulation results show that the system performance is significantly improved. Copyright © 2010 John Wiley & Sons, Ltd.     

Non-regenerative satellite switched FDMA (SS/FDMA) payload technologies

Satellite switched frequency division multiple access (SS/FDMA) satellite systems are new adaptations of the basic FDMA architecture for multiple beam spacecraft. Present multibeam satellite systems feature on-board interbeam connections operating on a transponder channel basis, e.g. 72 MHz. SS/FDMA on board connectivity is based on much narrower channels and consequently achieves a much better utilization of spectrum resources whenever connectivity requirements are of the order of fractions of a transponder bandwidth. This work presents a critical analysis of various non-regenerative SS/FDMA satellite systems, identifies the technological requirements to be met in order to achieve the practical realization of SS/FDMA on-board processors and, finally, proposes two novel variable bandwidth variable centre frequency (VBVCF) demultiplexers with continuous and discrete reconfigurability.     

Capacity of synchronous coded DS SFH and FFH spread-spectrummultiple-access for wireless local communications

The performance of synchronous spread-spectrum multiple-access (SSMA) communications based on direct-sequence (DS), slow frequency-hopped (SFH), and fast frequency-hopped (FFH) systems for wireless local communications of micro-cellular personal communications is analyzed. Using an indoor multipath fading channel model with clusters of arriving rays, we investigate multiuser DS systems with RAKE and diversity reception by selection combining (SC), multiuser SFH systems with equal-gain (EG) diversity reception, and multiuser FFH systems with correlated EG and self-normalization (SN) combining techniques. Reed-Solomon codes are considered to further improve the system performance. Given a fixed available bandwidth with narrow band interference (NBI), capacities and packet error rates are determined under various system configurations. Total capacities of hybrid frequency-division multiple-access (FDMA)/SSMA (DS and SFH) systems are compared with those of wide-band SSMA systems. For high data rate communications, wide-band DS-SSMA systems have larger capacities than hybrid FDMA/DS-SSMA systems. For low data rate communications, a capacity comparison between wide-band DS-SSMA and hybrid FDMA/DS-SSMA systems depends on fading statistics. Hybrid FDMA/SFH-SSMA systems have larger capacities than wide-band DS-SSMA systems, FFH-SSMA systems could not provide satisfactory performance due to correlation among hopping bands     

Digital mobile telephone system using TD/FDMA scheme

Multiple access is an indispensable technique for efficient radio spectrum utilization in mobile radio systems, because a large number of subscribers can be connected only when they require radio channels. Frequency division multiple access (FDMA) scheme using single channel per carrier (SCPC) has been widely used. However, the SCPC-FDMA scheme has some problems, such as difficulty in setting up a large number of base station transceivers and in realizing a low-cost highly stabilized local oscillator. A time and frequency division multiple access (TD/FDMA) scheme, which is a combination scheme of TDMA and FDMA, is proposed as one of the possible solutions for these problems. After explaining the background of the proposal, some of the restrictions of the TD/FDMA scheme resulting from the land mobile radio channel characteristics are described. Basic concept of the digital mobile radio telephone system using TD/ FDMA scheme is then presented. An example of the possible system design is finally shown.     

用TMS320C6x实现2M路QPSK信号全数字化整体解调算法研究

本文提出并证明了一种群路FDMA/QPSK(SCPS/QPSK)信号全数字化整体解调的新方法,该方法根据信道构成特点和信号调制方式,将直接分路法和常规多相FFT分离法相结合,构成了一种简化的等效多相FFT分路方法,接着将输出的数字信号直接送到数字式解调器,实现了多载波信号的全数字化整体解调,其特点是软件和硬件结构简单、系统计算量小,且易于DSP实时实现,现已用该算法进行了32路FDMA/QPSK信号整体解调的计算机仿真实验,结果表明该方法是可行的;目前已用最新数字信号处理器TMS320C6201硬件板对此方法的关键技术进行了实时仿真.     

New representation of FDMA traffic and associated on-board routers

A new mathematical representation is proposed for the interbeam connectivity matrix of FDMA traffic in communication satellite systems. A new kind of on-board FDMA router based on this representation is described     

A new transfer matrix formalism for the analysis of fiber ringresonators: compound coupled structures for FDMA demultiplexing

A method of analyzing fiber-ring resonators which is based on the transfer matrix technique is presented. The method is described and used to analyze known structures and compound coupled-ring resonators. Application of these structures as demultiplexers in FDMA (frequency-division multiple-access) systems is discussed