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%.

Asymptotic sum rate of MMSE receivers in multi-user distributed antenna systems

In this paper, the asymptotic sum rate of a multi-user distributed antenna system （DAS） is analyzed. To mitigate inter-user interference, minimum mean squared error （MMSE） receivers are utilized to cooperatively process received signals in the uplink. It shows that inter-user interference is efficiently mitigated and the uplink sum rate of a multi-user DAS is greatly improved by adopting MMSE receivers. For very large number of users and remote antennas, the asymptotic uplink sum rate of MMSE receivers is derived by using virtue of the random matrix theory, which can be The approximation is verified to be quite accurate by Monte Carlo simply calculated in an iterative way simulations.

Multi-User Connection Performance Assessment of NOMA Schemes for Beyond 5G

Non-orthogonal multiple access(NOMA)is proved to be useful to satisfy the requirements of beyond 5th generation such as massive multi-user connection.Here we compare the performances of two NOMA schemes:low code rate spreading(LCRS)scheme and interleaver division multiple access(IDMA)scheme.It is found that LCRS is superior to IDMA when number of users is small due to coding gain achieved.While IDMA is preferred when number of users is high because repetition applied in IDMA can suppress multi-user interference effectively.And interleaver is important in IDMA for randomizing the interference.Also,this paper evaluates the impact of channel decoder.It is observed that Log-MAP decoder has much better performance than that of Max-Log-MAP when number of users is large.Thus,it is recommended to use Log-MAP decoder in NOMA in high user overloading case.We also compared the performance of NOMA by using different type of channel codes.We find that NOMA using specific convolutional code has a better performance than that of using specific LDPC code when number of users is high.

A New Approach to Multi-user Detection in DS-CDMA

A graph model is constructed for the Multi-user Detection of DS-CDMA system. Based on it, a Hopfield-like algorithm is put forward for the implementation of optimum receiver. Compared with the Hopfield approach, it has a higher computational complexity but better performance.

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。

Active anti-noise transmitters and receivers

In general, the low-frequency capability of noise reduction of conventional anti-noise transmitters and receivers is not encouraging, but more and more sound energy of the modern high-intensity noise environments concentrates in that frequency range. Active anti-noise transmitters and receivers, which are developed from active ear defenders, supply the devices not only the benefit of advanced low-frequency anti-noise capability, but also a selectivity in sound reduction. The latter virtue ensures a high intelligibility of speech when the low-frequency noise is highly attenuated. On the basis of ref. [1], a thorough discussion on the principles, structures and experimental results of active anti-noise transmitters and receivers are given in this paper.

基于同侧解耦型电场耦合机构的多发射多接收无线电能传输系统

近年来,随着供电水平要求的提高,单发射单接收的电场耦合无线电能传输(EC-WPT)系统难以满足不同功率等级应用的需求。采用多发射多接收的EC-WPT系统可以有效地扩展输出功率等级。然而,在考虑耦合机构的全电容模型的情况下,因为传能通道间的耦合关系,多发射多接收的EC-WPT系统会存在系统失谐问题。为了解决此问题,该文提出一种基于同侧解耦型耦合机构的双发射双接收的EC-WPT系统。首先,建立一个典型的双发射双接收EC-WPT系统模型,分析同侧耦合对系统谐振的影响效果。然后,提出基于分裂极板的解耦型耦合机构的结构,论证其应用在EC-WPT系统电路中的解耦效果并分析了其解耦原理、耦合系数及偏移性能。最后,搭建了一个功率为200 W的实验样机。实验结果表明,所提出的耦合机构具有较好的同侧解耦特性,基于该耦合机构的EC-WPT系统能在不同工作条件下始终保持谐振状态。

一种通信收发电路的设计及其特性分析

阐述一种低功耗、高ESD性能的通信收发芯片,该芯片遵循的RS-485标准。针对该芯片的特性做出详细介绍,包括该芯片的整体功能、框图和引脚定义以及典型应用。探讨芯片特有的记性判断功能和相关电路设计,给出该芯片的ESD设计思路,包括芯片应用在通信电路的信号设计中,需要考虑的关键技术。

基于复合式随机码雷达系统实现入侵监测

面向安防区域的入侵监测过程包括区域边界的入侵报警和区域内部的入侵跟踪。然而,现有的入侵探测雷达技术难以兼顾区域边界和内部的同时监测,并且存在多入侵探测距离分辨率低和抗干扰能力弱的缺陷。提出并实验验证了一种面向入侵监测的复合式随机码雷达系统。该雷达系统结合了基于泄漏电缆的导波雷达和基于喇叭天线的一发多收雷达。前者用于实现区域边界的入侵报警,后者继而负责区域内部的入侵跟踪,最终实现监测区域的全面覆盖并消除监测盲区。此外,该雷达系统采用高速、正交的随机码信号作为上述两种雷达的发射信号。实验结果表明所提出的雷达系统不仅可以实现多个入侵者的同时报警和跟踪,而且具有强抗干扰能力。受益于随机码信号的高速率和自相关特性,导波雷达和一发多收雷达可以分别实现30 cm和15 cm的高距离分辨率,且抗干扰容限可以达到33.5 d B。

有源相控阵雷达TRM高功率微波在线测试系统

高功率微波(HPM)是系统电磁环境效应评估中的重要项目之一。针对有源相控阵雷达“前门”耦合窄带HPM效应评估需求,通过HPM效应评估不同试验方法比较分析,提出采用多端口高隔离“魔T”、耐高功率吸收式滤波器与隔离器等关键微波器件,构建基于传导注入法的收发组件(TRM)高功率微波效应评估实时在线测试系统,针对典型频段TRM开展效应试验,获取相应试验数据,验证了该测试系统是合理可行的。

复杂电磁环境下的T/R组件设计

为使高频高速大功率收发(T/R)组件在复杂电磁环境下可靠稳定工作,本文对组件的开关控制、组件电源与地、组件布局与屏蔽等进行分析,提出了注意要点,并给出了设计方法。在T/R组件开关控制设计中,通过一对延迟与共轭延迟电路保证收发时间长于驱动开关时间,解决共模干扰问题;通过脉宽检测及最高切换速度约束,解决差模干扰问题;在组件电源与地的分析中,着重强调了接地间距不超过信号波长的1/20。在布局与屏蔽的设计中,着重分析了腔体谐振波长。文中给出了实例模块,并就上述3点设计要点进行了对照分析,达到在复杂电磁环境下T/R组件稳定可靠工作的目的。

新一代多普勒天气雷达强度定标研究

天气雷达回波强度的强弱直接影响预报员对降水强度的判断,在重大气象灾害天气过程中,回波强度偏差有可能导致漏报而产生无法挽回的损失,中国气象局提出“到2022年底全国新一代天气雷达反射率因子标准偏差平均值从4.5 dB降低到3.5 dB”的目标,就是为了提高雷达监测均一性,降低客观因子对预报质量的影响。该文对岳阳、长沙、湘潭、益阳雷达产品对比分析,利用数据平均偏差方法计算雷达回波强度的扩散特征,得出岳阳雷达回波强度较其他3部雷达均偏弱约4 dB以上的结论,并采用“对点测量”方法对岳阳雷达进行重新标定,将平均偏差降低至2.5 dB以内,有效降低了中尺度区域内不同雷达之间的平均偏差,增强了回波强度一致性,对提高雷达业务可用性具有重要的现实意义。