Spectrum for pulse Frequency Modulation

This paper gives a spectrum expression which is simple and has a clear physical conception for pulse frequency modulation signal,and has been confirmed by an experiment simultaneously.     

Spectrum for Pulse Interval Modulation Signal

A static approach method method is used to get the spectrum expression of the pulse interval modulation signal.The expression is simple,has a clear physical concept and it has been confirmed by a simultaneous experiment .     

Auditory—Spectrum Quantization Based Speech Recognition

Ａｕｄｉｔｏｒｙ┐ＳｐｅｃｔｒｕｍＱｕａｎｔｉｚａｔｉｏｎＢａｓｅｄＳｐｅｅｃｈＲｅｃｏｇｎｉｔｉｏｎＷｕＹｕａｎｑｉｎｇＨａｏＪｉｅＬｕＤａｊｉｎＬｉＸｉｎｇＺｈｕＸｕｅｌｏｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｏｎｉｃＥｎｇｉｎｅｅｒｉｎｇ，...     

Designing of Acousto—optic Spectrum Analyzer

The structure of the acousto- optic spectrum analyzer was investigated including the RF amplifying circuit, the optical structures and the postprocessing circuit, and the design idea of the module was applied to design the spectrum analyzer. The modularization spectrum analyzer takes on the performance stabilization and higher reliability, and according to different demands, the different modules can be used. The spectrum analyzer had such performances as the detecting frequency precision of 1 MHz, the detecting frequency error of 0.58 MHz, detecting responsivity of 90 dBm and bandwidth of 50 MHz.     

Chaotic Spread- Spectrum Communication using Discrete-Time Synchronization

ＣｈａｏｔｉｃＳｐｒｅａｄＳｐｅｃｔｒｕｍＣｏｍｍｕｎｉｃａｔｉｏｎｕｓｉｎｇＤｉｓｃｒｅｔｅＴｉｍｅＳｙｎｃｈｒｏｎｉｚａｔｉｏｎＷａｎｇＨａｉａｎｄＨｕＪｉａｎｄｏｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＴｅｌｅｃｏｍｍｕｎｉｃａｔｉｏｎｓＥｎｇｉｎｅ...     

Spectrum Illumination for 3— Surface Imaging System

A method using spectrum illumination to reconstruct 3-D bject image is a new concept in the field of computer vision.The design of optical illumination system is crucial this method.Several ways to achieve multicolor spectrum illumination are discussed.A prism illumination system is designed by means of aligning symmetrically the prism at the mid-wavelength(nd=1.806 274)of light path and using reflection collimating lens,cylindrical expending lens and two optical shutters.The relations between deviation angles and light wavelengths are given,and some 3-D reconstruction results are presented.     

最新的生产测试系统——Spectrum系列

美国Teradyne(泰瑞达)公司于1996年11月12日在德国慕尼黑推出了第一台采用VXI结构的生产测试平台,以满足对最新的表面贴装电路板测试的要求。在电子产品展示会上的演示首次证实了新一代的Spectrum 8800系列产品是第一个建立在集成的VXI系统结构上的电路板测试系统。它主要应用于在线测试和电路板功能测试领域。     

Segment-Adaptive Spread Spectrum Audio Watermarking Using NSGA-Ⅱ

In the field of robust audio watermarking,how to seek a good trade-off between robustness and imperceptibility is challenging.The existing studies use the same embedding parameter for each part of the audio signal,which ignores that different parts may have different requirements for embedding parameters.In this work,the constraints on imperceptibility are first analysed.Then,we present a segment multi-objective optimization model of the scaling parameter under the constrained Signal-to-noise ratio (SNR) in Spread spectrum (SS)audio watermarking.Additionally,we adopt the Non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ) to solve the proposed model.Finally,we compare our algorithm(called SS-SNR-NSGA-Ⅱ) with the existing methods.The experimental results show that the proposed SS-SNR-NSGA-Ⅱ not only provides flexible choices for different application demands but also achieves more and better trade-offs between imperceptibility and robustness.     

浅谈南京地铁 ATS 系统 SINAUT Spectrum 平台

南京地铁ATC(列车自动控制)系统采用Solaris系统环境、SINAUT Spectrum控制实现平台和VICOS控制界面。目前被关注比较多的是Spectrum的操作系统环境:Solaris操作系统以及在Spectrum基础上的VICOS控制平台。文中根据南京地铁一号线ATS系统,描述了SINAUT Spectrum的运用、系统构架、系统组成以及各个组件的功能。     

Measuring Fingerprint Image Quality Using the Fourier Spectrum

The fingerprint image quality has a significant effect on the performance of automatic fingerprint identification system. A method for measure of fingerprint image quality based on Fourier spectrum is proposed. First the band frequency which corresponds to the global average period of ridge is searched. Then the quality score of the fingerprint image is computed by measuring relative magnitude of the band frequency components. The method is verified to have good performance by experiments.     

计算机工作站近况简述—IEEE Spectrum阅读笔记

IEEE Spectrum1992年4月号第25～56页登载5篇文章,从各个角度报道计算机工作站的进展近况。现根据这5篇文章,择要作简单综述,供大家参考。     

Properties of Light Emission Spectrum of Double-barrier Tunnel Junction

Fabricated are the double-barrier light emission tunnel junctions successfully. Introduced are the fabrication process and light emission characteristics. The spectra of the junctions are measured and analyzed especially. Their spectrum wavelength including main wave peak（locates at 450 nm～500 nm） of the double- barrier junction shows a ＂blue shift＂ in comparison with that of the single-barrier Metal/Insulator/ Semiconductor（MIS） or Metal/Insulator/Metal（MIM） junction（wave peak locates at 620 nm-740 nm）. This phenomenon should be due to the occurrence of the electron resonant tunneling in the double-barrier junction.     

Editorial Personal,Mobile Radio and Spread Spectrum Communications

ＥｄｉｔｏｒｉａｌＰｅｒｓｏｎａｌ，ＭｏｂｉｌｅＲａｄｉｏａｎｄＳｐｒｅａｄＳｐｅｃｔｒｕｍＣｏｍｍｕｎｉｃａｔｉｏｎｓＺｈｏｕＪｉｏｎｇｐａｎ；ＣｈｅｎｇＲｕｍｉｎｇ（ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＰｏｓｔｓａｎｄＴｅｌｅｃｏｍｍｕｎｉｃａ...     

Capacitance-frequency Spectrum Characterization of Organics/Metal Schottky Diodes

An organics/metal Schottky diode is fabricated using 3, 4： 9, 10-perylenetetracarboxylic- dianhydride（PTCDA） thin film sandwiched between ITO and Au by simple thermal evaporation technique. The current-voltage（I-V） characteristics are investigated at room temperature in open air. The results show the rectification ratio is in excess of 100. From the capacitance-frequency（C-f） and capacitance-voltage（C-V） measurements, the Schottky barrier height between 0.2-0.3 eV is obtained according to standard Schottky theory.     

Spectrum仪器数字化仪与AWG被用于全新水声实验室

<正>美国杨百翰大学物理与天文系的声学研究小组将Spectrum仪器领先的数字化仪与信号发生器作为其全新水下声学实验室核心。新实验室对声波如何在水中传播方面的研究可谓是一大进步,这得益于其模拟出了一个微缩版的海洋环境。该实验室能够对声波在不同水层中的行为以及它们如何在岩石、     

一种基于Spectrum原子的雷达辐射源信号识别方法

为了提高雷达辐射源信号的正确识别率以满足现代电子对抗的需求,该文提出了一种新的雷达辐射源信号识别方法。在过完备多尺度Spectrum原子库基础上,采用匹配追踪(MP)方法对信号进行原子分解,并通过FFT降低MP搜索过程的时间复杂性,在此基础上,对本征Spectrum原子参数进行有效降维,提取具有分类意义的原子特征向量,同步实现信号的自动分类和参数估计。实验结果表明,该方法在低信噪比环境下不仅可以获得高的信号类别正确识别率,同时具有准确的参数估计结果,证实了所提出方法的有效性。     

Cooperative Spectrum Sensing Based on Centralized Double Threshold in MCN

Cooperative spectrum sensing appears popular currently due to its ability to solve the issue of hidden terminal and improve detection performance in Cognitive Radio Networks. Meanwhile, double threshold based energy detector has attracted much attention for its low computational complexity and superior performance. Motivated by this, a cooperative spectrum sensing scheme is proposed in this paper based on centralized double threshold in the maritime communication networks(MCN), where the energy value of received signal in each cognitive node is forwarded to the fusion center for final decision based on double thresholds. Additionally, the proposed scheme is further optimized for the decisions that the energy is within the scope of maximum threshold and minimum threshold. Simulation experiments verify the performance of the proposed method.     

Raman Scattering Spectrum Analysis of GaP and Its luminous Materials

Abstract: The Raman scattering spectra of n- type GaP(doped S) single crystal and red and green luminous materials grown on the n - type GaP (doped S) single crys-tal substrate by liquid - phase epitaxy are analyed. The results show that the spectra of GaP single crystal and its luminous materials include not only the first - order longitudi-nal optical photons and transverse optical phonons Raman scattering peaks, but also the peaks of the bound excitons, bound electrons and bound holes.     

电子计算机近年发展动态简述—IEEE Spectrum阅读笔记

凡是研究和开发光纤通信系统、光纤通信网和数据通信网的同志,必须熟练使用计算机并了解国际上计算机的动态。近悉张煦教授写了《电子计算机近年发展动态简述》和《计算机工作站近况简述》两篇文章,在上海交大中青年教师中传阅,反应极好,有较大参考价值。本刊拟分两期登出,推荐给读者。