正交UBSK调制的功率谱优化

高效的调制和解调技术对数据传输具有重要的意义.推导了统一的正交二元偏移键控(UBSK)信号的功率谱密度表达式,去除了高次谐波,获得了基本波形的优化结果,提高了频谱效率.通过仿真,探讨了优化的功率谱密度随参数θ和τ的变化规律.结果表明:一定的参数条件下,优化后的功率谱密度相比优化前能实现约30 dB的边带衰减.     

BOC调制信号研究

随着新一代导航系统一欧洲Galileo卫星导航系统的建设和美国GPS现代化研究的进展,新型的卫星导航信号结构成为关注的热点,尤其是新型的调制方式-BOC调制(Binary Offset Carrier)有利于降低信号问的互相干扰,改善定位性能,成为新一代GPS M码和Galileo导航系统的主要选择.本文重点讨论BOC调制信号的定义、功率谱密度、相关函数以及"峰值跳跃"的捕获方法.     

基于扫频二进制偏移副载波的伪码扩频调制体制及其特性的研究

该文基于常规二进制偏移载波(BOC)调制体制的数学模型,提出一种新型的基于扫频二进制偏移载波调制(FC-BOC)的伪码扩频体制。在这种调制体制中,BOC调制体制数学模型中的固定频率二进制偏移载波被改进为线性扫频二进制偏移载波,使之不仅继承了BOC信号的性质,还具有更加独特的性质。仿真研究和算法实验表明:FC-BOC调制体制保留了BOC调制体制的主要优点,特别是具有狭窄的主相关峰和出色的副峰抑制特征而避免了多相关峰模糊性,功率谱密度函数呈现类似带通白噪声功率谱密度函数的形态。FC-BOC调制体制信号生成算法、接收算法的结构与常规BOC调制体制类似,算法复杂度相当于常规BOC调制体制,适合纯数字编程设计实现。     

CBOC信号处理中的二次采样方法

为了降低信号捕获跟踪运算量,针对Galileo信号CBOC调制提出了一种新的CBOC信号处理中的二次采样算法。分析了CBOC信号调制方式及功率谱密度,介绍了CBOC信号二次采样算法,提出了CBOC信号处理二次采样方法的处理模型。仿真结果表明,CBOC信号处理中的二次采样算法可以实现信号的CBOC解调,降低了运算量并简化了Galileo接收机的捕获跟踪设计。     

BOC调制信号研究

随着新一代导航系统一欧洲Galileo卫星导航系统的建设和美国GPS现代化研究的进展,新型的卫星导航信号结构成为关注的热点,尤其是新型的调制方式--BOC调制（Binary Offset Carrier）有利于降低信号问的互相干扰,改善定位性能,成为新一代GPSM码和Galileo导航系统的主要选择。本文重点讨论BOC调制信号的定义、功率谱密度、相关函数以及“峰值跳跃”的捕获方法。     

基于谱分析的OFDM调制识别新方法

针对正交频分复用(OFDM)信号与单载波信号调制识别,提出了3个基于功率谱特征的识别参数。根据OFDM信号功率谱边沿陡峭的特性,通过对归一化功率谱进行分析、统计和曲线拟合,提取3个参数,实现加性高斯白噪声信道(AWGN)条件下OFDM信号与9种单载波信号的识别仿真。该文识别参数具有特征参数易于提取、识别准确率高的优点。     

信号功率谱密度的物理基础

借助于信号对简谐振子和简谐振子阵列的作用,定义了信号的瞬时能量谱密度,进一步引入了信号的瞬时能量、功率谱密度、功率、能量谱密度及总能量等基本物理量,给出了功率谱密度的主要性质以及功率谱密度与其它各物理量之间的关系。     

晶体管放大器相位噪声的正交优化设计

本文给出了频标放大器输出级相位噪声功率谱密度的公式。为了降低相位噪声,用正交法对电路参数进行了优化设计。实验结果表明,放大器经优化设计后,其频率稳定度(阿仑方差)优于(35)10-13/s。     

Galileo系统中MBOC调制信号及性能分析

MBOC(Multiplexed Binary Offset Carrier)调制是GalileoE1频段以及GPS L1C频段推荐使用的一种优化调制方式。与BOC调制相比,MBOC调制方式的功率谱密度函数提供了更为丰富的高频分量,因此具有更高的伪码跟踪精度和抗多径性能。Galileo E1 OS采用了CBOC(6,1,1/11)(Composite Binary Offset Carrier)的方式实现MBOC调制。通过MATLAB仿真,对该信号的自相关函数、频谱特性进行了研究,并且通过与BOC调制信号的比对,证明了MBOC在码跟踪特性和抗多径性能方面的优越性。     

L-波段掺铒光纤放大器增益谱特性研究

对掺铒光纤放大器 (EDFA)在L 波段 (L Band ,15 70～ 16 10nm)的增益谱特性进行了理论和实验研究。理论和实验研究得出在最佳反转粒子数密度 (N=0 39) 条件下 ,掺铒光纤L Band的平坦增益谱宽为 2 2nm(± 0 5dB) ,抽运功率与输入信号功率呈线性关系。实验测得L BandEDFA单信道小信号增益为 33dB。     

导航信号副载波调制频谱仿真平台设计

在导航信号中,副载波调制用于实现谱分离和更优的导航性能。目前的副载波调制形式主要有二进制偏移载波BOC、混合二进制偏移载波MBOC、交替二进制偏移载波AltBOC和二进制编码序列BCS等。在导航信号设计中,需要针对不同的副载波调制参数下的频谱特性进行仿真和对比,设计了一种基于GUI的副载波调制信号的频谱仿真平台,能够方便进行功率波形、自相关和谱分离系数(SSC)的参数仿真和对比。     

ALTBOC调制信号抗干扰性能研究

由于环境中存在诸多电磁辐射干扰,因此如何有效评估全球卫星导航系统（GNSS）信号的抗干扰性能是一个亟待解决的问题。首先,本文利用干扰误差包络曲线对交替二进制偏移载波（ALTBOC）信号进行了在单音干扰和白噪声干扰两种情况下的抗干扰仿真分析,并和其他调制信号的抗干扰性能进行对比,仿真结果可为后续的信号体制研究提供参考。     

MBOC信号模拟及其性能评估

在全球卫星导航系统的现代化框架中,MBOC调制信号是新近提出的一种调制方式,将成为GalileoE1OS和GPSL1C的候选信号,因而MBOC数字中频信号的产生对于新的导航信号结构的研究和新一代接收机的研制具有极其重要的意义。对MBOC信号的时域和频域特性进行了理论分析、对其产生方式进行了仿真验证。设计开发了相应的数字中频信号模拟器,生成了CBOC和TMBOC两种实现方式下的MBOC信号,并采用软件接收机进行了闭环测试,得到了预期的结果。     

Complete alternative binary offset carrier modulated signals (AltBOC signals) with variable and constant envelopes for new-generation satellite radio navigation systems

The formation and structure of four- and eight-component complete alternative binary offset carrier modulated signals (AltBOC signals) for new-generation satellite radio navigation systems (SRNSs) (in particular, the Galileo and BeiDou-2 SRNSs) are considered. A four-component complete AltBOC signal has a time-variable envelope, while the envelope of an eight-component complete AltBOC signal is constant. The envelopes and phases of such AltBOC signals are analyzed for various values of the multiplicity coefficients of meander pulses. The combination components of an eight-component complete AltBOC signal are plotted, and the features of these components that ensure the time constancy of the envelope are revealed. A classification of AltBOC signals is proposed. Practical characteristics are analyzed on the basis of the AltBOC (15, 10) modulation, which is typical of the Galileo and Compass SRNSs.     

一种有效的OFDM载波频率偏移的盲估计

导出了具有循环前缀（CP）和虚子载波的正交频分复用（OFDM）通信系统信号的薮学模型。提出了基于PM—ESPRIT算法的0FDM系统载波频率偏移（CFO）偏移不变性的估计算法。经过粗略估计,该算法可以同时获得频率偏移和包含信道信息的矩阵,它们均有利于接收信号的偏移补偿和解调。仿真结果说明了该方法是有效的。     

软件GNSS中频信号模拟器

由于具有结构灵活、开放性强以及成本低的优势,软件GNSS(Global Navigation Satellite System)信号模拟器可成为GNSS接收机设计验证的高效平台。面向GPS/Galileo组合系统,阐述了软件GNSS中频信号模拟器的架构与实现,主要功能模块包括卫星星座仿真、接收机轨迹生成、传播通道特性仿真(包括电离层模型、对流层模型、多径模型、干扰模型)、数字中频信号生成。最后,对这一信号模拟器所产生的GNSS信号(包括GPS L1 C/A,GalileoE1 CBOC)进行了验证。     

Correlation functions of single symbols of meander signals in new-generation satellite radio navigation systems

Mathematical models of meander noise-like signals (binary offset carrier modulated signals (BOC signals)) of new-generation satellite radio navigation systems (SRNSs), in particular, the modernized GPS, the Galileo system, and the QZSS are presented. An analytic expression for the correlation function (CF) of single symbols of meander pulses is obtained for the arbitrary value of the multiplicity coefficient. The properties of CFs of various meander symbols are analyzed. The features of CFs are revealed for the even and odd values of the multiplicity coefficient. Examples of CFs are considered, and CFs of single symbols of BOC signals applied in new-generation SRNSs are plotted.     

Complex meander pseudorandom code sequences and alternative binary offset carrier modulation (AltBOC modulation) in new-generation satellite navigation systems

Complex meander pseudorandom sequences (MPRSs) that are the basis for formation of alternative binary offset carrier modulated signals (AltBOC signals) for new-generation satellite radio navigation systems (in particular, the Galileo and Compass systems) are considered. The properties and characteristics of MPRSs are analyzed. Analytical expressions for the spectral densities and power spectrum densities of complex and complex conjugate meander symbols (MSs) of the MPRS of a ranging code are found for various values of the multiplicity coefficient of meander pulses. The modulating function of an elementary AltBOC signal is considered. The power spectrum densities of complex and complex conjugate MSs are plotted and analyzed for typical values of the multiplicity coefficient.     

BOC调制信号频谱特性及仿真分析

BOC调制技术是一种广泛应用于GPS的现代化以及伽利略系统中新型信号调制技术。为研究其频谱特性,分析了BOC调制技术的基本原理及信号的产生过程,应用Matlab软件对其频谱特性进行了仿真,阐述了这种信号调制方式的优点;此外对其扩展技术MBOC,CBOC,TMBOC以及AltBOC做了简要介绍,对进一步研究导航信号现代化具有一定意义。     

Binary‐offset‐carrier modulation techniques with applications in satellite navigation systems

An important aspect in designing the modulation scheme for various satellite systems, such as the modernized GPS and Galileo, is to obtain good spectral properties and suitable spectral shaping. For example, in the future satellite navigation systems, some of the main goals are: low interference with the existing GPS signals, good root‐mean‐square (RMS) bandwidth, good time resolution (in order to allow the separation between channel paths and to decrease the synchronization errors) etc. Starting from the recently proposed cosine‐ and sine‐BOC modulation families for GPS and Galileo systems, we introduce a new, generalized family, denoted here by double‐BOC (DBOC) modulation. We derive and analyze the properties of the power spectral densities (PSD) and autocorrelation functions (ACF) of the DBOC modulation with various orders, we show its relationship with BPSK, sine‐ and cosine‐BOC modulations, and we illustrate via several examples how to choose optimally the parameters of this new modulation family, according to different optimization criteria. The examples are targeting at applications such as the design of suitable modulations for Galileo open service (OS) and public regulated service (PRS) signals, but the authors believe that the DBOC concept might be useful to other satellite‐based applications, when the available bandwidth is large enough. Copyright © 2006 John Wiley & Sons, Ltd.