超宽带(UWB)极窄脉冲的产生与实现

针对超宽带通信技术迅速发展的需要,详细分析了利用双极性晶体管的雪崩特性产生超宽带极窄脉冲信号的原理并介绍了技术现状。本方案在微波双极性晶体管串行级联的基础上,采用了并行同步触发的工作方式,极大地减少了时延与上升时间,产生了皮秒级的极窄脉冲。电路具有结构简单、成本低、性能好及应用价值高等优点。     

基于煤矿井下UWB脉冲产生电路的设计与研究

介绍了我国煤矿矿井无线通信的现状,提出将超宽带无线通信技术应用于井下。针对UWB脉冲的幅频特性,详细分析了晶体管雪崩效应理论和工作原理,利用此方法设计出多级并联同触发窄脉冲发生电路,提高了脉冲的幅值,降低了脉冲的时延和宽度,并通过仿真得以实现。此电路工作稳定,可靠性高,通过对电路参数修正,可适应不同的通信领域。     

超宽带高速通信系统射频发射机的设计与实现

介绍一种利用负阻器件产生超宽带多脉冲信号的射频发射机。该射频发射机可以产生宽度为5ns、重复周期为100MHz、峰一峰值电压可达3.2V 的高斯包络正余弦信号,并可通过加置功率放大器来满足特殊场合下的通信需求,功放增益达到20dB。分析讨论了电路原理与设计方法,实际测量结果显示,该发射机产生的脉冲信号具有良好的波形,是一种适合于超宽带通信系统的射频发射机。     

一种基于超宽带MIR运动传感器的电路实现

介绍一种超宽带MIR运动传感器的实现方法,并对其中微功率超宽带脉冲产生电路、超宽带相关检测电路的实现作了较为详细的描述。用该传感器对不同材质目标进行了探测灵敏度试验、穿透性试验,达到了预期效果。     

超宽带无线电中纳秒级脉冲产生研究

在分析现有超宽带无线电的载体—窄脉冲产生方法优缺点的基础上,提出产生超宽带纳秒级脉冲的逻辑框图,并由此设计相应的电路原理图、PCB版图,经实物调试测出输出波形,最后指出该电路的应用领域。     

单峰值冲击电压的测量方法

本文介绍一种精确测量高速单峰冲击正脉冲幅值的方法和电路。这种电路具有结构简单测量迅速,读数直观,能满足一般小信号的测量要求。如将输入端接一无感分压器还能满足雷击试验和高频高压冲击脉冲幅值的测量要求。     

超宽带窄脉冲的设计与实现

本文简单介绍了超宽带信号的定义和形式,重点分析了常用的脉冲生成方法,给出了两种方案实现窄脉冲的具体电路和测试结果。     

基于半导体开关和脉冲变压器的高压脉冲电路的 过电压抑制

脉冲变压器具有升压比高、可靠性好、体积小、价格低等优点,被广泛用于高压脉冲电路。 然而,受到漏感影响,会产生过电压,不仅增大了损耗,还可能导致开关过电压击穿。该文分析了 过电压的产生机理,比较了常规过电压抑制措施的效果及其缺陷,提出一种新的过电压抑制电路, 给出了新电路的拓扑结构、工作原理和电路参数选择依据,并通过建模仿真验证了新过电压抑制电 路的效果。最后,采用这种过电压抑制电路,研制了一台紧凑重频高压脉冲发生器,可以产生幅值 11 kV、频率 2 kHz、脉宽 2 μs 的脉冲,并用于驱动悬浮电极介质阻挡放电负载,能够稳定产生低温 等离子体。     

基于ARM9的脉冲触发与数据采集控制模块设计

为适应超宽带微波近场成像系统对脉冲触发及数据采集的要求,提出了一种基于ARM9微处理器的控制模块.它通过接口电路控制脉冲源,产生用于目标成像的超宽带窄脉冲;通过串口与存储示波器进行通信,对数据采集进行控制.给出了此控制模块结构和主要硬件电路设计,介绍了控制软件的设计流程,并给出了模块中发送与接收控制功能的具体实现方法.该控制模块的应用举例结果表明,该设计方案能有效地实现成像系统中的数据发送与接收控制,满足了系统设计要求.     

重频超宽带脉冲对混频器的干扰特征分析

重频超宽带脉冲可对多种电子设备与电子器件产生干扰。针对电子器件的干扰效应,着重从仿真分析和实验两方面研究了重频超宽带脉冲对无源混频器的干扰特征。分析了混频器对超宽带脉冲信号的响应特性,给出了不同参数条件下重频超宽带脉冲信号对混频器及混频滤波电路的干扰特征。研究表明,作为干扰信号,重频超宽带脉冲信号并不能影响混频器正常工作;当重频超宽带脉冲信号与通信信号一起注入混频器时,混频器可实现其正常的变频功能,而作为衡量混频器工作性能的重要指标,变频损耗可认为基本不变;重频超宽带脉冲信号经过混频滤波电路后变为同中频信号同样频率的连续波信号,其对混频滤波电路的干扰以及之后电路的干扰类似定频连续波信号干扰。     

导波雷达物位计发射电路的设计分析

导波雷达物位计是一种利用时域反射（TDR）原理实现的高性能物位计,因其测量精确,性能稳定,在现代工业的多个领域得到了广泛地应用。雷达物位计一般采用窄脉冲发射-反射-接收的工作方式进行物位测量,可见脉冲发射电路是其中至关重要的一环。论文在分析和比较常用的几种极窄脉冲产生电路的基础上,提出了采用射频三极管串行级联、并行触发的发射电路设计方案。这样设计不仅可以使三极管在较低偏置电压下雪崩导通,还能有效地消除雪崩依次时延和减小输出脉冲的上升时间。测试结果显示该发射电路能够产生脉宽901．9ps ,幅值2．25V的极窄脉冲,满足了导波雷达物位计对发射脉冲的要求。     

Beamforming of UWB pulse array and its implementation

This paper firstly introduces a realistic ultra-wideband (UWB) pulse model and discusses the principle of sensor array beamforming for UWB pulse signals. Then the differences between a UWB pulse array and narrowband sinusoidal array are studied. Based on it, the problem of realizing a digital and applicable variable delay circuit (VDC) to compensate the channel propagation delay accurately for UWB pulse array beamforming is addressed. In our work, fractional sample delay compensation filters (FDCF) are combined with delay lines to build up accurate VDCs. As a result, the Lagrange interpolation method based on maximally flat criterion is found to be most suitable for the fixed beam steering; and Farrow structure is recommended to satisfy the need of rapid beam adjustment. In the simulation experiments, two kinds of directivity pattern for an UWB pulse array are studied and compared with that of sinusoidal array. The effectiveness of the presented scheme is verified by the simulation results, which show that the VDC implementation by digital lines and FDCF can remarkably improve the performance of the directivity patterns of UWB pulse array especially for the system with low sampling rate.     

超声导波任意波形脉冲激励源的设计与实现

根据适用于激励超声导波的信号的特征,在改进直接数字频率合成器(DDS)结构的基础上,运用DSP+ FPGA等工具设计出适合导波检测用的任意波形脉冲激励源.该激励源可根据实际检测条件调整激励波形的类型且激励信号中心频率、周期数、幅值、重复频率等参数均可设置.经实验验证,此激励源能生成导波检测所需要的各种波形信号,且能扩展...     

基于ECL逻辑器件的高频相移信号发生电路

提出了一种基于脉冲抑制原理的可编程ECL逻辑器件的高频相移信号发生电路。给出了输出相移量为2π/32的20 MHz信号的频率稳定性测试实验结果,对于1 s～10 000 s的积分时间,艾伦标准方差值σy(τ)<10-9。该电路具有电路设计原理简单、可复制性强、电路体积小、成本低等优点。     

ASRSP——一种新的并发程序测试准则

可达性测试是目前较为成熟的一种并发程序测试方法,该方法解决了如何生成最小完备偏序测试序列集的问题.但研究表明,对于一般规模的并发程序,这一测试序列集仍然太大,以至穷尽测试无法完成.因此,目前亟需能投入实际应用的并发程序测试准则和相应的测试序列生成算法.本文提出了一种实用性较高的并发程序测试准则:全发送接收语句对(ASRSP),并针对该准则提出了一种新的并发程序测试方法:全发送接收语句对可达性测试(ASR-SP-RT).该方法利用可达性测试生成测试序列集的完备性来保证覆盖所有的发送接收语句对,并在每次生成新序列 之后及时去掉对覆盖剩下发送接收语句对无作用的序列,从而达到约简测试序列集的目的.     

基于FPGA的某型发动机超声波探测电路设计

固体火箭发动机的钢壳、绝热层、衬层、推进剂多层粘接结构的脱粘缺陷,很容易引起灾难性后果,对它的检测已经成为一项极其重要的工作,文章设计了一种基于FPGA的超声波探测电路,构建了一个可编程片上系统（SOPC）,并编写了PWM控制组件。以NiosⅡ为核心控制产生脉冲宽度、重复频率可调的超声波激励脉冲,配合高速A／D实现回波信号的采集和存储。缩短了设计周期,简化了硬件电路,为后续研究便携式超声波检测仪奠定了良好的基础。     

Complex radio frequency (RF) communications with virtual pulses

A novel complex pulse forming technique has been developed using ultra wideband (UWB) frequency concepts where multiple carriers are modulated by the pulse width of the primary signal source. Specialized modulation of the pulse train provides an effective communication medium with inherent advantages of an UWB system. The multiple frequency nature of the non-traditional “pulse” formation provides a means of implementing UWB without the necessity of complex pulse formation of the classical UWB. The particular example of the research implemented in this paper allows explicit user choice of the specific UWB frequencies, e.g., ISM frequencies, to avoid current restrictions of the Federal Communications Commission (FCC). The reported method also contains an implicit property to support secure information transmission to receivers at known distances.The objective of this technique is an easy to form communication pulse having UWB low energy advantages along with the freedom of implementation without license requirements from regulating authorities, while adhering to the set limits of intentional radiators. The method chosen in this case was based on having the sum of energies from multiple frequencies remain within the restricted radiation limits at the correlated receiver. Included in the implementation technique is the inclusion of the signal fading effect as part of the modulation technique. The relevance of this pulse forming technique is in the simplicity of spreading the transmitted power among multiple frequencies without the issue of decay factor in the current methods. The result presented gives two sets of relative amplitudes of the transmitted frequencies identifying the transmitted character, e.g., 0 or 1. A form of amplitude encryption, due to the RF signal fading effect was also presented as advantage in the technique.     

取样脉冲对平衡式取样积分微分电路性能影响

取样脉冲是影响超宽带无线电引信接收机性能的关键因素。在分析取样积分微分电路工作原理的基础上,建立了其频域和时域数学模型。结合无载波信号的时域多普勒效应,提出了基于Matlab的超宽带无线电引信接收机输出信号时域仿真方法。研究了取样脉冲宽度和幅度对电路输出波形的影响,结果表明:电路完全对称时,输出信号幅度只与取样脉冲宽度有关,但并非单调关系;非对称时,电路达到稳态前产生一个脉冲信号,脉冲幅度与取样脉冲的幅度成正比,宽度成反比。     

Advanced system‐level simulation paradigm for ultra‐wideband systems using SCERNE platform

In this article, a progressive system‐level simulation framework is developed based on Simulation de Chaînes d'Emission/Réception Nouvelle gEnération (SCERNE) platform to simulate an ultra‐wideband (UWB) impulse radar transmitter and accurately predict its performance. With the purpose of demonstrating the usefulness of the SCERNE ability in system‐level modeling, we present and simulate a simplified structure of UWB impulse radar transmitter. First, after simulation each component in different circuit‐level tools such as ADS, CST, and HFSS, each part has been modeled by using different modeling methods to transfer their data into MATLAB environment. Then, we duplicate the transmitter structure in SCERNE toolbox to validate the results. The advantage conferred by the proposed SCERNE toolbox is that fast and accurate bilateral modeling method is available at multi‐medium structures in contrast with conventional unilateral modeling, and so a lower memory and higher accuracy of the behavioral model is achieved. It can also be beneficial when the user is looking for system‐level, as the increased components amounts can help as a surrogate model. The system model can be easily extended to other UWB radar systems by simply changing the input pulse shape, UWB channel environment, transceiver topology, etc. Various effects such as signal quality, and pulse shape that can easily investigate and re‐optimize for high performance are using the developed model. To validate the practicality of the proposed paradigm, the simulations and predictions through model results are being outlined.