光开关选通的光纤激光水听器时分复用阵列

为了降低传感器系统的成本及体积,利用光纤激光传感单元的特性,采用光开关选通的光纤激光水听器时分复用技术,构建了实用的基于光开关的4元光纤激光水听器时分阵列。进行了理论分析和实验验证,分析了使用光开关选通的光纤激光水听器时分复用阵列方案的选通脉宽和损耗,指出了各通道光脉冲对干涉信号的采样率的限制因素。结果表明,光开关选通的光纤激光水听器时分阵列可以很好地完成复用信号的采集和复用,实验中4元时分复用水听器相邻通道的串扰为-17dB。     

8路光纤水听器高速时分复用系统设计

当前,光纤水听器阵列的多路复用技术已成为研究的重要课题之一,而时分复用(TDM)技术被认为是最简单有效的方案。本文详细介绍了8路光纤水听器高速时分复用系统的设计过程。分析比较了梯形式及平行式两种光路结构的优缺点,并得出最佳光路方案。选择TI公司生产的TMS320F206芯片作为系统控制核心,采用AD公司新出的采样频率达1 M的16位AD7677作为A/D转换器,设计出8路光纤水听器高速时分复用系统,测试结果表明系统通道间串扰在-30 dB左右。对水听器阵列时分复用技术的发展具有相当的参考价值和借鉴意义。     

8路光纤水听器高速时分复用系统设计

当前，光纤水听器阵列的多路复用技术已成为研究的重要课题之一，而时分复用(TDM)技术被认为是最简单有效的方案．本文详细介绍了8路光纤水听器高速时分复用系统的设计过程．分析比较了梯形式及平行式两种光路结构的优缺点，并得出最佳光路方案．选择TI公司生产的TMS320F206芯片作为系统控制核心，采用AD公司新出的采样频率达1M的16位AD7677作为A／D转换器，设计出8路光纤水听器高速时分复用系统，测试结果表明系统通道间串扰在-30dB左右．对水听器阵列时分复用技术的发展具有相当的参考价值和借鉴意义．     

RF-TV叠加EPON系统中拉曼串扰的研究

采用等效系统传递函数法得出了1 490 nm数据光波对1 550 nm有线电视(CATV)光波拉曼串扰的理论计算公式,并用相对强度噪声指数(RIN)来表示拉曼串扰,修正了CATV通道载噪比(CNR)的计算公式.进行了实验验证.计算及实验结果表明,拉曼串扰与1 490 nm光功率有关,可使CATV系统低频端的(CNR)下跌5 dB,而且以太空闲字符码流会造成62.5 MHz及其倍频分量较大的单频干扰.指出了克服拉曼串扰的方法.     

40通道100G间隔AWG的研制

本文利用BPM算法设计了40通道100G间隔的AWG,并利用PLC标准工艺制作了AWG器件.该器件的插入损耗为4 dB,相邻通道串扰为30 dB,非相邻通道串扰为38 dB,1 dB带宽为0.26 nm,实现了预先设计的目标.     

雷达与导航、声纳与对抗

0525462多防线防御系统目标突防概率的计算[刊,中]/卢发兴//系统工程与电子技术.—2005,27(6).—1061-1065(D2)0525463光纤水听器时分复用系统串扰的理论分析与仿真研究[刊,中]/李舰艇//半导体光电.—2005,26(3).—256-260(D2)     

多光通道结构光三维测量系统误差补偿研究

本文通过对多光通道结构光三维测量系统误差分 析发现,相机采集光强受通道间串扰以及投影、采 集图像器件非线性响应等误差影响。在分析串扰和非线性误差影响投影和采集光强的基础上 ,提出了针对 相机采集光强进行系统误差补偿的数学模型。投影0－255灰度图像到 白色平板并由相机采集,计算得到系 统内各光通道的非线性响应参数,以及投影纯色彩色条纹到白色平板计算得到各通道间串扰 系数,通过构 建的误差模型,同时补偿了非线性和串扰误差。实验结果表 明,经过误差模型修正后,展开 相位差从1.044 rad 降到0.121 rad,测量误差从0.707 mm减少到0.058 mm。本文提出的补偿模型从系统误差分析出发,可对串 扰和非线性误差同时测量与补偿,有效提高了多光通道结构光三维测量系统的测量精度。     

相位误差对AWG波分复用器非相邻通道串扰影响的分析

分析了工艺制作过程中引入的阵列波导相位误差以及由其所引起的非相邻通道间串扰性能的劣化,给出了相应的分析公式.利用该公式,可以简捷地分析所设计的AWG型器件的非相邻通道串扰水平,为优化AWG型器件的设计提供依据.     

相位误差对AWG波分复用器非相邻通道串扰影响的分析

分析了工艺制作过程中引入的阵列波导相位误差以及由其所引起的非相邻通道间串扰性能的劣化,给出了相应的分析公式.利用该公式,可以简捷地分析所设计的AWG型器件的非相邻通道串扰水平,为优化AWG型器件的设计提供依据.     

非常见问题解答 来自ADI公司的电话记录中奇怪但真实的故事

转换器中的串扰问:在选择模数转换器时,是否应该考虑串扰问题?答:当然!串扰可能来自几种途径:从印刷电路板(PCB)的一条信号链到另一条信号链,从IC中的一个通道到另一个通道,或者是通过电源时产生。理解串扰的关键在于找出其来源及表现形式,是来自相邻的转换器、另一个信号链通道,还是PCB设计?     

一种性价比高的TDM MIMO雷达系统设计和实验

基于大量使用昂贵的收发组件,传统的具有M阵元发射阵列和N阵元接收阵列的相干多输入多输出(MIMO)雷达系统实际应用受高成本的限制,文中提出一种性价比高的时分复用(TDM) MIMO雷达系统设计。首先,建立TDM MIMO雷达的收发结构模型;其次,从理论上对距离估计和角度估计进行了仿真比较,将TDM MIMO雷达与单输入多输出雷达通过实验对比验证;最后,结果证实相比于相同阵列的传统MIMO雷达,TDM MIMO雷达不仅目标波达方向性能未受影响,而且以较低的成本实现较高的角度分辨率。     

卫星网络管理系统控制信道设计

设计了一套用于卫星网络管理系统的控制信道。采用TDM/TDMA专用控制信道和复接控制信道互为备份的方式保证信息传输的畅通,2种信道都可保证卫星网管所有功能的完成。主用TDM/TDMA专用控制信道,一旦专用信道中断,采用复接控制信道。复接控制信道与业务复接在一起利用业务信道传输网管信息。TDM/TDMA专用控制信道由链路适配器和突发卫星调制解调器组成,重点描述其设计方案。     

Optimal insertion of pilot symbols for transmissions over time-varying flat fading channels

Two major training techniques for wireless channels are time-division multiplexed (TDM) training and superimposed training. For the TDM schemes with regular periodic placements (RPPs), the closed-form expression for the steady-state minimum mean square error (MMSE) of the channel estimate is obtained as a function of placement for Gauss-Markov flat fading channels. We then show that among all periodic placements, the single pilot RPP scheme (RPP-1) minimizes the maximum steady-state channel MMSE. For binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) signaling, we further show that the optimal placement that minimizes the maximum uncoded bit error rate (BER) is also RPP-1. We next compare the MMSE and BER performance under the superimposed training scheme with those under the optimal TDM scheme. It is shown that while the RPP-1 scheme performs better at high SNR and for slowly varying channels, the superimposed scheme outperforms RPP-1 in the other regimes. This demonstrates the potential for using superimposed training in relatively fast time-varying environments.     

Area efficient computing structures for concurrent error detection in systolic arrays

A method of designing testable systolic architectures is proposed in this paper. Testing systolic arrays involves mapping of an algorithm into a specific VLSI systolic architecture, and then modifying the design to achieve concurrent testing. In our approach, redundant computations are introduced at the algorithmic level by deriving two versions of a given algorithm. The transformed dependency matrix (TDM) of the first version is a valid transformation matrix while the second version is obtained by rotating the first TDM by 180 degrees about any of the indices that represent the spatial component of the TDM. Concurrent error detection (CED) systolic array is constructed by merging the corresponding systolic array of the two versions of the algorithm. The merging method attempts to obtain the self testing systolic array at minimal cost in terms of area and speed. It is based on rescheduling input data, rearranging data flow, and increasing the utilization of the array cells. The resulting design can detect all single permanent and temporary faults and the majority of the multiple fault patterns with high probability. The design method is applied to an algorithm for matrix multiplication in order to demonstrate the generality and novelty of our approach to design testable VLSI systolic architectures.This work has been supported by a grant from the Natural Sciences and Engineering Research Council of Canada.     

Cooperative Game Theory and the Gaussian Interference Channel

In this paper we discuss the use of cooperative game theory for analyzing interference channels. We extend our previous work, to games with N players as well as frequency selective channels and joint TDM/FDM strategies. We show that the Nash bargaining solution can be computed using convex optimization techniques. We also show that the same results are applicable to interference channels where only statistical knowledge of the channel is available. Moreover, for the special case of two player 2 × K frequency selective channel (with K frequency bins) we provide an O(K log/sub 2/K) complexity algorithm for computing the Nash bargaining solution under mask constraint and using joint FDM/TDM strategies. Simulation results are also provided.     

A 1024-channel fast tunable delay line for ultrafast all-optical TDM networks

Based on a passive k-stage feed-forward delay line structure, this letter presents a novel scheme which allows fast tuning among as many as 2/sup k//spl times/2/sup k/ ultrafast time-division multiplexed (TDM) channels in all-optical networks. At a lower speed, a simple selection rule is applied at the input and output of the structure to set the state of the delay. In the experimental demonstration, the delay line can be tuned to any of the 1024 50-Mb/s channels in a 50-Gb/s all-optical TDM network with a five-stage structure and two E/O modulators. The average reconfiguration time is about 20 ns.     

Novel sampling technique for digital video demultiplexing,descrambling and channel selection

Describes a novel method of distributing a large number of digital video channels over a passive optical fibre network, while allowing the use of baseband binary receive equipment. The synchronous TDM is sampled, and receive channels are descrambled using a programmable delay-lock loop     

A 24-channel implantable neural recording based on time and frequency-division multiplexing

This paper presents a novel approach to encapsulate prerecorded neural signals in implantable neural recording microsystems. We have increased the number of channels and the reconstructed neural signal quality in the receiver by combining time-division-multiplexing (TDM) and frequency-division-multiplexing (FDM) method. Reducing the number of channels in each TDM module is the fundamental advantage of this method that leads to reduced crosstalk noise. We evaluate some possible configurations and propose an optimized system that has less power dissipation and area occupation than other configurations. A 24-channel implantable neural recording based on the optimized system is designed in both system and circuit level. In this system, first, channels are divided into three 8-channel groups then after multiplexing in the time domain, they are combined together by FDM method. Finally, a frequency modulator wirelessly transmits neural signals to an external setup. In addition, we adjust local carrier frequencies and the bandwidth of TDM to synchronize detection without transmitting pilot carrier. To justify the system operation, using 0.18 μm CMOS technology, we design the system in circuit level. The designed circuit consumes a power of 1.39 mW at a supply voltage of 1.8 V. This leads to a power consumption of 58 μW per channel.     

40-Gbit/s TDM transmission technologies based on ultra-high-speedICs

This paper presents 40-Gbit/s time division multiplexing (TDM) transmission technologies based on 0.1-μm-gate-length InP high electron mobility transistor IC's and a scheme for upgrading toward a terabit-per-second capacity system. A 40-Gbit/s, 300-km, in-line transmission experiment and a dispersion-tolerant 40-Gbit/s duobinary transmission experiment are described as 40-Gbit/s single carrier system applications on dispersion-shifted fiber. An ultra-high-speed receiver configuration using a high-output-power photodiode is introduced to realize fully electrical receiver operation beyond 40 Gbit/s. The high-sensitivity operation of the optical receiver (-27.6 dBm@BER=10^-9) is demonstrated at a data bit rate of 50 Gbit/s for the first time using a unitraveling carrier photodiode. A dense wavelength division multiplexing (DWDM) system operating up to terabits per second can be easily realized on a zero-dispersion flattened transmission line using ultra-high speed TDM channels of 40 Gbit/s and beyond. An experiment demonstrates 1.04-Tbit/s DWDM transmission based on 40-Gbit/s TDM channels with high optical spectrum density (0.4 bit/s/Hz) without dispersion compensation