2.5 Gbit/s monolithic ICs for optical fiber transmitter and receiver in 0.35 μm CMOS process

2.5 Gbit/s monolithic integrated circuits （ICs） for optical fiber transmitter and receiver in 0.35 μm CMOS （complementary metal-oxide-semiconductor transistor） process are presented. The transmitter, which includes a 4： 1 multiplexer and a laser diode driver （LDD）, has four 622 Mbit/s random signals as its inputs and gets a 2.5 Gbit/s driving signal as its output; the receiver detects a 2.5 Gbit/s random signal and gets four 622 Mbit/s signals at the output. The main circuits include a trans-impedance amplifier （TIA）, a limiting amplifier, a clock and data recovery （CDR） unit, and a 1： 4 demultiplexer （DEMUX）. Test results prove the logic functions of the transmitter to be right, and the 10% to 90% rise and fall times of transmitter＇s output data eye diagram are 211.1 ps and 200 ps, respectively. The sensitivity of the receiver is measured to be better than 20 mV. The root mean square jitter of the DEMUX＇s output data is 15.6 ps and that of the clock after 1： 4 frequency dividing is 1.9 ps. Two chips are both applicable to 2.5 Gbit/s optical fiber communication systems.

Receiver Power Allocation and Transmitter Power Control Analysis for Multiple-Receiver Wireless Power Transfer Systems

As different power has its own receivers,this paper analyzes and designs a multiple-receiver wireless power transfer(WPT)system systematically.The equivalent circuit model of the system is established to analyze the key parameters including transmitter power,receiver power,transmission efficiency,and each receiver power allocation.A control circuit is proposed to achieve the maximum transmission efficiency and transmitter power control and arbitrary receiver power allocation ratios for different receivers.Through the proposed control circuit,receivers with different loads can allocate appropriate power according to its power demand,the transmitter power and system efficiency do not vary with the change of the number of receivers.Finally,this control circuit is validated using a 130-kHz WPT system with three receivers whose power received is 3:10:12,and the overall system efficiency can reach as high as 55.5%.

Design of Transmitter Combiner for 800MHz Trucking Mobile Communication

The structural composition, scheme selection and component design of a five-channel transmitter combiner for 800MHz trucking mobile communication system (TMC) is proposed. More attentions have been paid to the analysis and design of the high-Q microwave resonant cavity with accurate tuning structure. Also, a model transmitter combiner designed by the authors is proposed. Test results of the combiner are given. It has been proved that the technical specifications of the combiner have reached an advanced technical level compared with the products of the same kind imported from abroad.

Optimizing Optical Attocells Positioning of Indoor Visible Light Communication System

Visible light communication(VLC),which is a prominent emerging solution that complements the radio frequency(RF)technology,exhibits the potential to meet the demands of fifth-generation(5G)and beyond technologies.The random movement of mobile terminals in the indoor environment is a challenge in the VLC system.The model of optical attocells has a critical role in the uniform distribution and the quality of communication links in terms of received power and signal-to-noise ratio(SNR).As such,the optical attocells positions were optimized in this study with a developed try and error(TE)algorithm.The optimized optical attocells were examined and compared with previous models.This novel approach had successfully increased minimum received power from−1.29 to−0.225 dBm,along with enhanced SNR performance by 2.06 dB.The bit error rate(BER)was reduced to 4.42×10−8 and 6.63×10−14 by utilizing OOK-NRZ and BPSK modulation techniques,respectively.The optimized attocells positions displayed better uniform distribution,as both received power and SNR performances improved by 0.45 and 0.026,respectively.As the results of the proposed model are optimal,it is suitable for standard office and room model applications.

A Survey on Terahertz Communications

With the exponential growth of the data traffic in wireless communication systems, terahertz(THz) frequency band is envisioned as a promising candidate to support ultra-broadband for future beyond fifth generation(5G), bridging the gap between millimeter wave(mmWave) and optical frequency ranges. The purpose of this paper is to provide a comprehensive literature review on the development towards THz communications and presents some key technologies faced in THz wireless communication systems. Firstly, despite the substantial hardware problems that have to be developed in terms of the THz solid state superheterodyne receiver, high speed THz modulators and THz antennas, the practical THz channel model and the efficient THz beamforming are also described to compensate for the severe path attenuation. Moreover, two different kinds of lab-level THz communication systems are introduced minutely, named a solid state THz communication system and a spatial direct modulation THz communication system, respectively. The solid state THz system converts intermediate frequency(IF) modulated signal to THz frequency while the direct modulation THz system allows the high power THz sources to input for approving the relatively long distance communications. Finally, we discuss several potential application scenarios as well as some vital technical challenges that will be encountered in the future THz communications.

Guarding Legal Communication with Smart Jammer:Stackelberg Game Based Power Control Analysis

This paper investigates a power control problem in a jamming system,where a separate smart jammer is deployed to ensure the communication security of the legal user.However,due to power leakage,the smart jammer may incur unintentional interference to legal users.The key is how to suppress illegal communication while limit the negative impact on legal user.A jamming counter measure Stackelberg game is formulated to model the jamming power control dynamic of the system.The smart jammer acts as a leader to sense and interfere illegal communications of the illegal user,while the illegal user acts as a follower.In the game,the impact of uncertain channel information is taken into account.According to whether illegal user considers the uncertain channel information,we investigate two scenarios,namely,illegal user can obtain statistical distribution and accurate information of interference channel gain and its own cost,respectively.This work not only proposes a jamming counter measure iterative algorithm to update parameters,but also gives two solutions to obtain the Stackelberg equilibrium(SE).The power convergence behaviours under two scenarios are analyzed and compared.Additionally,brute force is used to verify the accuracy of the SE value further.

AN ADAPTIVE CDMA RAKE RECEIVER

A new adaptive RAKE receiver is proposed which uses pilot sig-nal for channel estimation in CDMA down link communications. The configuration of the system is presented and the performance is also evaluated forboth adaptive RAKE receiver and the non-adapti

Equivalent Noise Models in Fiber Optical Communication Systems

An equivalent noise model of optical receiver amplifiers as shown in Fig.1 has been given in many fiber optical communication literatures. It is proved in this paper that this equivalent noise model is neither equivalent to the original one nor measurable. The main reason is that the position of the input impedance in this noise model is not the same with its in the typical noise model,but the same S vn , S in with the typical noise model are used. So the equivalent noise model above is wrong and is not fit to be taken into application.

Exploiting Geometric Advantages of Cooperative Communications for Energy Efficient Wireless Sensor Networks

Energy efficiency and enhanced backbone capacity is obtained by exploiting the geometric orientation of cooperative nodes in wireless sensor network. The cooperative communication in wireless sensor networks (WSN) gives us leverage to get the inherent advantages of its random node’s locations and the direction of the data flow. Depending on the channel conditions and the transmission distance, the number of cooperative nodes is selected, that participate in an energy efficient transmission/reception. Simulation results show that increasing the cooperative receive diversity, decreases the energy consumption per bit in cooperative communications. It has also been shown that the network backbone capacity can be increased by controlled displacement of antennas at base station at the expense of energy per bit.

Performance Analysis of Optical Wireless Communication System Employing Neuro-Fuzzy Based Spot-Diffusing Techniques

The spot-diffusing technique provides better performance compared to conventional diffuse system for indoor optical-wireless communication (OWC) system. In this paper, the performance of an OW spot-diffusing communication system using Neuro-Fuzzy (NF) adaptive multi-beam transmitter configuration has been proposed. The multi-beam transmitter generates multiple spots pointed in different directions, hence, forming a matrix of diffusing spots based on position of the receiver and receiver mobility. Regardless of the position of the transmitter and receiver, NF controller target the spots adaptively at the best locations and allocates optimal power to the spots and beam angle are adapted in order to achieve better signal-to-noise plus interference ratio (SNIR). Maximum ratio combining (MRC) is used in the imaging receiver. The proposed OW spot-diffusing communication system is compared with other spot-beam diffusion methods proposed in literature. Performance evaluation revels that the proposed NF based OW spot-diffusing communication system outperforms other spot-beam diffusion methods.

Modeling and Stability Analysis of a Communication Network System

In this work, the modeling and stability problem for a communication network system is addressed. The communication network system consists of a transmitter which sends messages to a receiver. The proposed model considers two possibilities. The first one, that messages are successfully received, while in the second one, during the sending process the transmitter breaks down and as a result the message does not reach the receiver. Timed Petrinets is the mathematical and graphical modeling technique utilized. Lyapunov stability theory provides the required tools needed to aboard the stability problem. Employing Lyapunov methods, a sufficient condition for stabilization is obtained. It is shown that it is possible to restrict the communication network system state space in such a way that boundedness is guaranteed. However, this restriction results to be vague. This inconvenience is overcome by considering a specific recurrence equation, in the max-plus algebra, which is assigned to the timed Petri net graphical model.

一种再生式机载遥测转发器硬件设计方法

文章讨论一种遥测信号转发器的设计与实现方法,这种转发器采用再生变频转发方式,接收信号解调后再变频调制发射供遥测地面站接收,可以在不增加转发器发射功率的情况下解决超视距通信问题。该转发器采用软件无线电设计思想,电路采用全国产器件实现,利用国产SOC芯片做为基带处理芯片,国产射频收发芯片实现正交上变频和下变频作为接收与发射通道,通过实验证明了基于全国产芯片的机载遥测转发器能够可靠地工作。

用于货架电子设备的准无线电能传输技术

本文提出了一种可为金属货架上的微功耗电子设备以准无线方式供电或充电的技术。该技术包括发射和接收两部分,高频发射电源连接到货架层板以提供电能,接收电路使用集总元件,可以内置到电子设备中。通过分析电场耦合,建立了单接收及双接收系统的电路模型,并分析了功率效率传输特性。仿真及实验系统验证了所提技术的可行性。结果表明,接收设备可在货架平台内的任意位置获得稳定的电功率。接收设备数量增加时,系统的传输效率得以提高。六接收设备时,单个功率仍能在500 mW以上,足以驱动显示牌类的微功耗电子设备。

基于超声非线性的固体火箭发动机药柱测厚方法

为了扩大对高衰减固体火箭发动机药柱的厚度测量范围,利用超声纵波在固体传播中产生静态分量(static components,SC)的理论。通过一发双收的反射式超声换能器组合,即发射端超声换能器工作频率为500 kHz,接收端超声换能器工作频率分别为50和500 kHz,完成多种厚度药柱的静态测量。测量结果表明,对于厚度较大的药柱,50 kHz超声换能器可以放大并接收由500 kHz超声纵波所激发的SC低频信号;对于厚度较小的药柱,500 kHz可以同时接收500 kHz基波信号和SC低频信号。相较于传统同频收发的换能器组合,该一发双收的换能器组合在不加大测厚盲区的同时,提高了可测量厚度范围,可以完成20~200 mm厚度范围内的测量,有一定的创新性和较好实用价值。

基于空间谱域的分布式无源雷达成像性能分析

无源雷达成像即利用空间中存在的多个辐射源和接收站,同时对同一目标进行多角度成像,从而获取丰富的目标特征信息,它是当前雷达成像领域的研究热点之一。文章对无源雷达成像性能的影响因素进行分析,从多个辐射源、多个接收站和目标组成的空间三维构型出发,建立了目标回波模型,推导出回波数据与点散射函数之间存在的空间谱域映射关系。以北斗卫星辐射源为例,使用后向投影(back projection,BP)算法对多点目标进行成像仿真。仿真实验从辐射源与接收站数量、辐射源与接收站排布间隔以及辐射源与接收站构型三方面,有效验证了空间谱填充与成像质量的关系,为后续无源雷达成像系统的设计提供理论支撑。

A review of ToF-based LiDAR

In recent years,propelled by the rapid iterative advancements in digital imaging technology and the semiconductor industry,encompassing microelectronic design,manufacturing,packaging,and testing,time-of-flight(ToF)-based imaging systems for acquiring depth information have garnered considerable attention from both academia and industry.This technology has emerged as a focal point of research within the realm of 3D imaging.Owing to its relatively straightforward principles and exceptional performance,ToF technology finds extensive applications across various domains including human−computer interaction,autonomous driving,industrial inspection,medical and healthcare,augmented reality,smart homes,and 3D reconstruction,among others.Notably,the increasing maturity of ToF-based LiDAR systems is evident in current developments.This paper comprehensively reviews the fundamental principles of ToF technology and LiDAR systems,alongside recent research advancements.It elucidates the innovative aspects and technical challenges encountered in both transmitter(TX)and receiver(RX),providing detailed discussions on corresponding solutions.Furthermore,the paper explores prospective avenues for future research,offering valuable insights for subsequent investigations.

一种电力特殊场景下提升低功耗无线发射机能效的计算方法

为了满足在偏远地区、地下场景等供电条件困难的环境下,无线通信设备供电时长要求,文章提出了一种低功耗无线发射机发射功率计算方法,通过整个无线通信信道损耗和sub-GHz低功率收发天线芯片的数据表计算出无线发射机发射功率。通过仿真计算,相比传统发射机发射功率计算方法,该方法更精确地计算出发射端所需要的最低发射功率,提升了无线发射机能效,从而使得无线通信设备满足偏远地区、地下场景等供电条件困难环境下的供电时长要求。

基于电磁法的地下金属管线探测系统分析

地下金属管道探测系统能够为市政建设工程开发与应用提供支持,近年来受到广泛关注。基于此,本文首先简单分析管线探测仪系统结构设计,然后深入探讨天线及后级信号处理电路设计方法,以供参考。

高山无线发射台的卫星接收天线防雷技术分析

阐述雷电的形成、危害和入侵途径,分析高山无线发射台防雷接地中的问题。提出雷电防护措施,包括严格要求发射塔避雷针的保护范围、电源前安装压敏电阻等避雷装置、中继传输的保护。

Study on multiple receiver systems in non-line-of-sight ultraviolet communication systems

In this article, multiple receiver effects in a non-line-of-sight （NLOS） ultraviolet （UV） communication system is studied. The idea of using multiple receivers for diversity reception is known as a practical, effective and widely applied technique in wireless communications. The current approach is to use multiple antennas at the receiver in order to improve the quality of the received signal. A method of modeling and simulation is proposed to depict the principle and feasibility of the multiple receiver adopted in UV communication. The study provides an insight to the channel characteristics and achievable capabilities of ultraviolet communication systems with multiple receivers. It provides guidelines for practical system design with discussions on trade off between the receiver gain and the additional cost.