基于MUX的PSK调制系统设计

载波的两种相位随二进制数字基带信号离散变化称为二进制移相键控（2PSK）。对BPSK和DPSK调制原理研究基础上,讨论了数字化处理2PSK调制系统的模块建立,在Max＋PlusⅡ开发环境中,用VHDL语言设计BPSK和DPSK调制,利用MUX模块完成了PSK调制系统,仿真和验证了其设计功能。     

基于软件无线电的数字通信信号产生技术

数字通信信号的产生主要是基带信号对载波进行调制,本文是通过软件无线电的思想来完成对基带信号可选择式的调制.本文设计中将2ASK、2FSK、2PSK三种调制方式集中于同一硬件平台之中,可以根据不同的要求采用不同的调制方式,改变了以往单一的调制方式,具有更大的灵活性.     

FSK/PSK调制的FPGA实现

基于DDS和VHDL硬件描述技术,采用大规模可编程门阵列FPGA,实现了FSK和PSK数字调制。介绍了m伪随机基带码元发生器、跳变检测器和DDS信号发生等模块。系统参数易修改、可移植性强、性能稳定。     

基于FPGA的FSK调制解调器设计

数字通信系统中的数字调制与解调技术包括幅度键控(ASK)、频移键控(FSK)和相移键控(PSK),而FSK是应用较广的一种调制与解调方式。利用VHDL语言设计了2FSK调制解调器,并通过QuartusⅡ仿真平台进行仿真验证,最后下载到FPGA芯片EP1K30QC208-2实现了2FSK调制解调电路。仿真及实验结果表明采用此设计方案是可行的,并具有速度快、可靠性高及易于大规模集成的优点。     

多种调制格式微波信号的光学产生方案

提出了一种基于偏振调制器（PolM）和Sagnac环级联的多调制格式微波信号的光学产生方案。理论分析了PolM在基带编码信号的驱动下产生偏振键控（PolSK）信号的基本原理,Sagnac环中嵌有两个马赫增德尔调制器（MZM）,分别对顺时针和逆时针传输的PolSK信号进行独立调制。通过合理调整两个MZM的驱动信号,实现了幅移键控（ASK）、频移键控（FSK）和相移键控（PSK）微波信号的产生。在仿真实验中,产生了比特率为2 Gbit/s的40 GHz ASK信号、20/40 GHz FSK信号和20 GHz PSK信号,同时验证了比特率和载波频率的宽带可调谐性。Sagnac环结构提升了系统的稳定性,并且针对每种调制格式的微波信号,在不改变链路结构的情况下其比特率和载波频率都可以通过控制基带编码信号和MZM的射频驱动来进行独立且灵活的调谐。     

基于FPGA的数字调制信号发生器的设计

以设计数字调制式信号发生器为目的,依据通信系统中模拟和数字调制方式的理论基础,采用现场可编程逻辑阵列技术（FPGA）,给出了一种具有数字调制功能的信号发生器的设计方法。该发生器具有ASK、PSK、FSK功能,各个模块采用VHDL语言设计,然后下栽到EPF10K10LC84—3芯片来完成硬件电路的连接与测试。     

MFSK调制电路的FPGA设计与仿真

频移键控(FSK)是用不同频率的载波来传递数字信号,并用数字基带信号控制载波信号的频率。笔者提出了一种基于DDS(Digital Direct Synthesizer)技术的MFSK调制器的FPGA实现方案,并根据DSP开发工具DSP Builder的优点,采用VHDL文本与Simulink模型图相结合的方法进行了FPGA设计与仿真。仿真结果验证了设计的正确性及可行性。     

一种正弦信号发生器的设计

设计一个以单片机和FPGA为核心,基于DDS AD9851的正弦信号发生器,能在100 Hz-15 MHz频率范围可调.通过AGC、幅度控制、调制电路、功率放大等模块实现AM、FM、ASK、FSK、PSK多种调制功能.同时FPGA实现直接频率合成技术,产生基波信号,控制AD9851产生载波信号.用户通过按键选择系统输出调制方式,操作简单.     

一种FSK信号调制解调电路的设计

介绍了一种FSK信号调制解调电路的设计思想,发送端采用锁相环芯片CD4046实现了基带信号的FSK调制,接收端采用普通鉴频法进行解调,将FSK信号转换为ASK信号,并采用检波和低通滤波电路恢复出其基带信号。该电路具有结构简单、成本低廉、工作可靠等优点,可适用于低速电力线载波通信中。     

基于FPGA的FSK调制与接收系统设计

频移键控是用不同频率的载波来传输数字信号,并用数字基带信号控制载波信号的频率。二进制频移键控是用两个不同频率的载波来代表数字信号两种电平。接收端收到不同的载波信号再进行逆变成为数字信号,完成信号的传输过程。本文主要介绍了一种基于FPGA芯片设计FSK调制解调器的基本原理,并使用相应的VHDL语言对该原理进行描述,该设计以ALTERA公司的大规模集成电路芯片为核心,使得电路简洁、可靠性高。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks