OFDM-PON系统中误码率测试的同步方法

伪随机二进制序列(Pseudo Random Binary Sequence,PRBS)作为测试码型,广泛应用于高速误码率测试中。通过分析并行PRBS生成原理,提出了一种误码率测试中同步的实现方法。由仿真和实际测试结果可知,该方法具有同步速度快、结构简单和消耗资源少等优点,已成功应用于2G OFDM-PON系统的研发与测试。     

以1.5Gbps运行的PRBS发生器

PRBS(伪随机二进制序列)或PN(伪噪声)发生器在数字数据传输中有广泛的应用(参考文献1).这些电路通常由带反馈的简单移位寄存器构成,它可以用作串行数据链路的测试源.     

空间激光通信中高速伪随机序列及多路器

在开展综合信息系统演示试验前,为了实现激光通信系统的单独测试,需对模拟的各种载荷选择性输出及对误码率进行测试。研制了一种基于FPGA的嵌入式智能多路器及高速伪随机序列生成器,设计高速并串转换电路及时钟电路实现高速伪随机序列的传输,速度可达3 Gbps,用于误码率测试。其中高速的伪随机序列速率智能可调,速率范围为750 M到3 G。设计兼容多种电平的差分多路器,数据传输的类型通过多路器选择性输出,输出的电平为固定的LVPECL。如:视音频的串行数据流,伪随机序列,模拟数据源。     

DVB-T中伪随机序列扰码器的FPGA实现

伪随机序列在伪码测距、导航、数字数据扰乱器、噪声产生器、通信加密中有着广泛的应用。在这些实际应用中,常常利用现场可编程门阵列（FPGA）来产生伪随机序列,这便于系统设计和测试的实现。针对数字地面电视广播（DVB-T）标准,以线性反馈移位寄存器电路为基础,设计了一种并行伪随机序列产生方法,该方法简单而高效地实现DVB-T系统码流数据的扰码。实验结果表明,MATLAB扰码算法结果与FPGA扰码模块仿真结果和硬件实现结果一致,该设计方法切实可行。     

12×2.5Gbit/s并行伪随机序列发生技术及在线误码块监测

利用FPGA产生并行高速伪随机序列和比特间插奇偶校验8位码误码块的方法实现了在线误码监测。建立了点到点并行高速光传输误码监测实验系统,该系统由12×2.5Gbit/s并行高速伪随机序列发生器、在线误码监测模块、12×2.5Gbit/s并行光接收模块和自制垂直激光阵列发射模块构成,并行光互联采用带宽为400MHz.km5米12芯62.5μm多模带状光纤。     

基于FPGA的FSK加密通信

主要介绍了二进制移频键控FSK通信过程中利用FPGA进行伪随机序列加密的实现方法.移频键控是信息传输中使用较早的一种调制方式,它具有实现容易,抗噪声与抗衰减性能较好的优点,在中低速数据传输中得到了广泛的应用.直接利用FPGA产生伪随机序列的方法可以为系统设计或测试带来极大的便利.给出了基于线性反馈移位寄存器电路,设计一种简洁的伪随机序列发生器的方法.这种方法所产生的随机序列不仅可具有极长的周期,而且还具有良好的随机特性.由于该伪随机序列可以被设计成任意长度,所以设计过程比较灵活.介绍了加密的设计理论、设计过程和硬件实现,该电路可进行下载生成实际电路,并应用到信息安全领域中.     

基于FPGA的多路伪随机序列发生器的设计与实现

传统伪随机序列构成优选对的数目较少，在码分多址系统中的应用受到限制。利用GW48实验平台和QuartusⅡ软件，采用有限域法寻找m序列优选对，以及采用自顶向下的设计方法，设计了一种基于FPGA的多路伪随机序列发生器，即G0LD序列发生器。实验测试结果表明该GOLD序列发生器具有良好的自相关性和互相关性，可广泛应用于通信、密码学、雷达、流媒体处理等领域。     

扩频通信中伪随机序列的捕获

１伪随机序列捕获的方法伪随机序列捕获的方法可分为串行搜索法和并行判决法两种。１．１串行搜索法串行搜索捕获是在本地伪随机序列和接收伪随机序列不同步的情况下，调整本地序列相位，逐一进行试验，直到发现某本地序列相位和接收序列相位基本一致为止，如图1所示。假设扩频系数为M，每码片两个采样时，需要进行2M次试验,则每次试验费时为伪随机序列一个周期的时间，即一个符号的时间。也就是说，在其它参量已同步且检测到无错误时，最多需要2M个符号后，才能对伪随机序列实现捕获。串行搜索捕获是以输入数据中伪随机序列相位为参考，…     

随机位序列发生器电路

随机位序列发生器是数据传输系统样机制作和测试用的基本设备,人们在测量BER(位差错率)和传输系统中与模式相关的效应时都使用这种发生器。与模式相关的效应包括基线漂移、数据抖动以及已复原时钟的抖动。大多数序列发生器通过具有适量反馈的移位寄存器产生PRBS(伪随机位序列),因此序列的长度有限,序列发生器要不断地重复产生同一模     

基于变结构混沌的伪随机序列发生器

为产生随机性能良好的伪随机序列,提出了一个新的变结构混沌系统。该混沌系统在一个开关函数控制下其系统结构随时间随机地转换,所产生的混沌信号是两个不同的混沌信号的混合,具有良好的复杂性。基于该变结构混沌系统设计了一种伪随机序列发生器,采用NIST标准和STS-2．0b测试套件对其产生的伪随机序列进行了统计性能测试,测试结果表明该伪随机序列发生器具有良好的随机性,可应用于计算机、通信、信息加密等领域中。     

43 Gb/s decision circuits in InP DHBT technology

Packaged master-slave D-flip-flops designed in InP DHBT technology with 150 GHz f/sub t/ and 180 GHz f/sub max/ are presented. Measurement results using a 43.2 Gb/s nonreturn to zero (NRZ), pseudo random binary sequence (PRBS) data (generated from 4 channels of 10.8 Gb/s, 2/sup 31/-1, PRBS data) and a 43.2 GHz clock, show a clock phase margin of 190/spl deg/. 2:1 Static frequency dividers designed using the D-flip-flops have been tested up to 50 GHz and show normal operation. These circuits are key building blocks in numerous front-end circuits used for 40 Gb/s optical communication systems.     

A spread-spectrum based synchronization technique for digitalbroadcast systems

A technique that has been verified experimentally to improve the synchronization efficiency of digital communication systems over present systems without sacrificing reliability is presented. This technique is called the spread-spectrum system pilot technique (SSPT). Incorporated into this technique are elements of tone-calibrated techniques (TCT) and spread-spectrum systems. In the SSPT system, the desired pilot tone is modulated by a pseudorandom binary sequence (PRBS) generator of finite duration and then linearly added to the source (customer) data that is actually being sent. At the receiver, the same finite PRBS sequence is used to decode the received signal. The system works because it provides an accurate version of the actual data carrier to be used in demodulation of the received signal. Based on the research presented, it is expected that this type of system will lead to better performance than currently used transparent-tone-in-band and other techniques used in multipath fading environments, which are especially problematic in mobile broadcast and communication applications     

Chaotic-laser-based true random sequence generation for spread-spectrum communications

We propose a scheme for spread-spectrum communications using true random sequences generated by chaotic semiconductor lasers as spreading codes.These sequences can eliminate the inherent periodicity of pseudorandom sequences,enlarge the capacity of spread-spectrum codes,improve communication security,and increase the number of users of the system.When a true random sequence with an appropriate length is used as the spread-spectrum code and the information speed is maintained constant,the system acquires a greater spreadspectrum gain and a lower bit-error ratio(BER) than the traditional spread-spectrum system.The communication security is also enhanced.The BER smoothly increases with the number of users,which indicates the good multipleaccess capability of the system.     

基于FPGA的PRBS伪随机序列的实现与研究

首先描述了伪随机序列的原理特性和生成方法，然后分析应用FPGA来实现伪随机序列的原理，并且详细讲述PRBs数据流的产生和检测的实现方法，利用FPGA器件的特殊结构，非常有效地节约了逻辑资源。然后利用仿真软件对设计进行了实现和验证。对于如何检测伪随机序列，提出两种不同的检测方法，做出比较并分析其利弊，最后指出伪随机序列的使用范畴。     

Statistically tailored binary sequence for improved error ratemeasurements in 256 QAM digital radio

The authors address considerations of repeatability and accuracy in the measurement of BER on a 256 QAM digital radio system. When viewed in terms of state occupancies and vector transition magnitudes, pseudorandom binary sequences (PRBSs) only weakly exercise the sequences of state occupancies and transition magnitudes that statistically characterise an infinite random QAM payload. This is further aggravated if the mapping of bits into QAM symbols is static in each PRBS repetition. We have synthesised and tested a binary sequence which better imitates the statistics of an infinite random sequence in the vector symbol space. In simulation trials, the new test sequence more closely predicts the BER obtained with a much longer nonrepeating random pattern     

用白噪声源实现高速真随机码

本文分析了用白噪声产生高速真随机码的基本原理.用HP346C宽带白噪声源和二级带有判决电路的D触发器,产生了高速非归零真随机码,避免了由亚稳态造成的延时抖动.     

基于混沌激光的500Mb/s高速真随机数发生器

基于光反馈半导体激光器产生混沌激光作为熵源,设计制作了放大器、比较器及触发器等高频电子器件,实现对混沌激光的模数转换,产生一路随机数,与另一路不相关的随机数异或处理,无需后续数字处理,最快可实现500 Mb/s输出。产生的随机数序列通过了美国国家标准与技术研究院(NIST)的统计测试标准(SP800-22)。该随机数发生器码率可调,易集成,有利于产品化。     

一种新型的高速时钟数据恢复电路的设计和验证

针对高速(Gbit/s)串行数据通信应用,提出了一种混合结构的高速时钟数据恢复电路。该电路结构结合鉴频器和半速率二进制鉴相器,实现了频率锁定环路和相位恢复环路的同时工作。和传统的双环路结构相比,在功耗和面积可比拟的前提下,该结构系统的复杂度低、响应速度快。电路采用1.8 V,0.18μm CMOS工艺流片验证,测试结果显示在2 Gbit/s伪随机数序列输入情况下,电路能正确恢复出时钟和数据。芯片面积约0.5 mm~2,时钟数据恢复部分功耗为53.6 mW,输出驱动电路功耗约64.5 mW,恢复出的时钟抖动峰峰值为45 ps,均方根抖动为9.636 ps。     

Application of mismatched filter theory to bandpass impulse response measurements

The Letter shows how a mismatched filter for the compression of a bandpass arbitrary length pseudorandom bit sequence (PRBS) may be generated. A comparison is made between the standard matched filter and the mismatched filter in terms of accuracy, dynamic range, noise gain, simplicity of implementation and flexibility to shape the probing pulse, when such filters are used for the determination of wideband bandpass impulse response measurements. This study was carried out in the context of mobile radio channel sounding.<>     

Information sources using chaotic dynamics

A sequence of binary random variables has found significant applications in modem digital communication systems. For such sequences, several kinds of linear feedback shift register sequences have been proposed. It is, however, well known in probability theory that the Bernoulli shift is a fundamental theoretic model of a sequence of independent identically distributed (i.i.d.) binary random variables. In this paper after reviewing fundamental subjects of chaotic dynamics, in particular a close relationship between information sources and Markov chains, we give the generation method of sequences of i.i.d. binary random variables using chaotic dynamics. Such a generation method is given as a sufficient condition composed of simple symmetric properties for some class of ergodic maps. Furthermore, we give the applications of such sequences: (1) to running-key sequences for stream cipher systems and (2) to a color image communication system through code-division multiple access channels and its extended version, a digital watermarking system. In addition, the performance of spread spectrum codes generated by a Markov chain is theoretically evaluated in asynchronous direct-sequence/code-division multiple access systems