正确选择微处理器复位监控电路

本文对阻容复位电路和监控器复位电路产生的复位脉冲的特性进行了对比分析，结果发现，在电源出现瞬时跌落的情况下，阻容复位电路可能无法产生所需的复位脉冲。另外，还讨论了如何正确选择复位门限电压。     

按键式电话机拔号电路故障分析与检修

按键式电话机拔号电路故障分析与检修林平按键式电话机拨号电路由拨号专用集成电路、键盘和外围电路构成，完成产生和发送正确的脉冲以及消除拨号时产生的“咯咯”声的任务。根据脉冲开关电路与通话电路的连接方式，拨号电路可分为并联和串联两种。井联脉冲拨号电路在拨号...     

介绍一种由脉冲列触发的交流调压电路

交流调压电路在电阻－电感性负载时采用文章介绍的脉冲列触发电路以后，就能有效地消除因移相角调节不当而产生的直流磁化现象，本文简要介绍了直流磁化产生的原因，重点阐述了脉冲列触发电路的几个主要环节。     

基于ADS软件的脉冲电路设计

基于电容微分结构设计脉冲产生电路。利用ADS软件对电路进行仿真和优化，脉冲宽度为1．5ns。对电路进行调试得到的结果与仿真结果基本一致。     

一种基于双三极管并联的UWB 窄脉冲发生器

脉冲产生器是IR-UWB通信系统的重要组成模块之一。提出了一种高可靠性的窄脉冲发生电路。该脉冲产生电路基于并联的双射频三极管所产生的雪崩效应与LC电路阻尼原理,产生一阶微分高斯脉冲波形。双三级管的并联设计加速了雪崩效应,降低了工作电压,易于电路实现。当其中单只三极管损坏时,电路仍然可以依靠另一只进行工作。实验测试结果表明：该电路所产生的脉冲峰峰值约为12.88V,脉冲宽度约为1.6ns,可以用于IR-UWB通信系统。     

一种基于SRD和NLTL的皮秒级脉冲产生电路

提出了一种利用SRD产生窄脉冲信号的方法,对其产生窄脉冲的机理进行了分析和仿真,为了使得脉冲宽度变得更窄,电路采用了NLTL结构,拓展了SRD产生窄脉冲的应用,文中分析了NLTL的工作原理。设计了基于SRD和NLTL的皮秒级脉冲产生电路,给出了测试结果,脉冲宽度为110 ps,幅度为3 V。     

超宽带Scholtz’s单周期脉冲的产生电路设计

以并联阶跃恢复二极管（SRD）窄脉冲发生器为基础,结合简单的RLC电路,设计一种直接产生Scholtz’s单周期脉冲的电路结构。这种脉冲近似二次微分高斯脉冲,是超宽带系统中使用较多的一种波形。文章主要讨论了电路原理与设计方法,并进行了仿真验证。仿真结果显示该电路所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窄脉冲信号产生电路。     

管道超声内检测发射电路设计

在深入分析超声检测发射电路的基础上，设计了基于RLC串联谐振的发射电路，电路以场效应管为开关元件，电感储能形成高频、高压脉冲，建立了发射电路理论模型，分析了电路参数对高压窄脉冲的影响，理论计算产生的宽频高压脉冲激励信号与实验测量结果一致。该电路不需要提供直流高电压，只需要5V单电源供电，就可稳定获得宽度小于1μs，幅度大于400V，且无余振的高压窄脉冲。电路具有结构简单、体积小、不需要直流高压、功耗低、易于集成等特点，满足管道超声内检测的要求。     

一种超宽带脉冲信号发生器的设计

介绍一种利用并联阶跃恢复二极管(SRD)产生超宽带窄脉冲信号的微带结构电路,该电路可产生宽度为1ns、重复周期为100MHz的窄脉冲信号,其峰值电压达10.44V。文章分析讨论了电路原理与设计方法,并重点研究了偏置电路与匹配电路的设计问题。测量结果显示该电路所产生的脉冲信号具有良好的波形,并且脉冲拖尾的振荡起伏很小,是一种适合于超宽带通信系统的窄脉冲信号形成电路。     

一种平衡输出皮秒级脉冲源的设计与应用

设计一种平衡输出皮秒级脉冲源电路,该电路由雪崩三极管电路和阶跃恢复二极管整形电路组成.雪崩三极管电路产生平衡输出的纳秒级脉冲信号,经阶跃恢复二极管整形电路整形产生平衡输出的皮秒级脉冲信号.文中分析脉冲源电路的工作原理,制作电路并进行测试.测量结果表明,设计的脉冲源电路可以产生平衡输出幅度±26 V、宽度253 ps、重...     

New design of 3.2–4.8 GHz generator for multi-bands architecture of UWB communication

In this paper a new design of Ultra-Wide Band (UWB) generator is presented. This circuit is the most important block in multi-bands transmitter architecture of UWB communication system. The proposed UWB generator is composed of multi-bands voltage controlled oscillator (VCO), mixer and rectangular pulse generator which consist of ring oscillator, time delay and AND gate function. The UWB generator is based on multiplying the rectangular pulse envelope to a continuous sinusoidal wave in order to generate the UWB signal. This UWB generator circuit produces an output signal which is characterized by the bandwidth of 1600 MHz divided into three sub-bands of 528 MHz, centered at frequencies of 3.432, 3.96, 4.488 GHz and the limited Power Spectral Density (PSD) is −41.44 dBm/MHz. The maximum amplitude of UWB signal is 214 mV, the pulse is during of 3 ns and the pulse repetition period (PRP) is 32 ns. The power consumption is approximately equal to 26 mW at a voltage supply of 2.5 V. This topology is designed in CMOS 0.35 μm AMS process technology.     

一种有载频超宽带脉冲源设计

针对无载频脉冲低频分量大、辐射效率低、频带可调性差等问题,设计了一种以阶跃恢复二极管、D触发器及超宽带调制器为主的宽频带、高重复频率、低振铃水平的有载频超宽带脉冲源。该脉冲源电路由驱动电路、高速开关电路、整形电路、超宽带调制器及振荡器电路组成。实测结果表明,脉冲源输出脉冲信号重复频率可达125 MHz,脉冲宽度600 ps（底宽）,脉冲振铃水平低于10%,峰-峰值为5.4 V,-10 dB带宽可达4.2 GHz。脉冲信号中心频率与载频相同,可在6.6~8.5 GHz之间灵活设置。利用所设计的脉冲源进行时域测量,其结果与矢量网络分析仪频域测量结果相比幅频特性均方根误差小于0.21 dB。该脉冲源可应用于超宽带时域测量、短距离高速无线通信、高精度室内定位等应用。     

Single-chip CMOS pulse generator for UWB systems

This paper presents a single-chip pulse generator developed for Ultra Wide Band (UWB) wireless communication systems based on impulse radio technology. The chip has been integrated in a CMOS 130-nm technology with a single supply voltage of 1.2 V. The basic concept is to combine different delayed edges in order to form a very short duration "logical" pulse, and then filter it, so as to obtain an UWB pulse. It is possible to vary the output pulse shape, and thus the corresponding spectrum, just by acting on the delayed edge combination. Furthermore, the pulse generator supports both position modulation (2-PPM) and polarity modulation (BPSK modulation) in order to convey data through the air. Its power consumption remains less than 10 mW for a raw data rate of up to 160 Mb/s. Spectral and temporal measurements of the single-chip pulse generator are presented with an illustration of the modulation effects on the power spectral density (PSD).     

On the Development of an Integrated CMOS-Based UWB Tunable-Pulse Transmit Module

A novel low-cost low-power fully integrated tunable transmit module composed of a tunable CMOS monocycle pulse generator and compact uniplanar antenna was designed, built, and tested for ultra-wideband (UWB) impulse systems. The CMOS tunable pulse generator integrates a tuning delay circuit, square-wave generator, impulse-forming circuit, and pulse-shaping circuit in a single chip using a standard low-cost 0.25-$muhbox m$CMOS process. It can generate a monocycle pulse and Gaussian-type impulse (without the pulse-shaping circuitry) signals with tunable pulse duration. A compact uniplanar UWB antenna was also developed and integrated directly with the CMOS pulse generator chip to form the complete integrated tunable UWB transmit module. Measured results show that the CMOS tunable pulse generator can produce a 0.3–0.6-V peak-to-peak monocycle pulse with 140–350-ps tunable pulse duration and a 0.5–1.3-V peak-to-peak impulse signal with 100–300-ps tunable pulse-duration, and the uniplanar antenna has less than a 18-dB return loss and is suitable for transmitting/receiving UWB time-domain impulse signals covering the entire UWB bandwidth of 3.1–10.6 GHz. Good agreement between measured and calculated performance is also achieved. The UWB transmit module was experimentally characterized and its performance is verified. This UWB module finds applications in various time-domain UWB systems including wireless communications and radar.     

Truly balanced pulse generator using microwave transistor and SRD

A novel efficient circuit for Ultra-WideBand (UWB) balanced sub-nanosecond monocycle pulse generation is presented. The pulse generator employs wideband bipolar transistor, step recovery diodes, Schottky diodes, and simple charging and discharging circuitry. Simple transient analysis and design of the circuit are presented along with their operating principle. The pulse generator produces truly balanced monocycle pulse with 500 ps pulse-width and 800 mV peak voltage. The generated monocycle pulse also has very symmetrical positive and negative portions and low ringing level. The presented pulse generator can be used as both a transmitter feeding UWB balanced antennas without broadband baluns and a balanced switching pulse generator that used in UWB receiver.     

High-Order Monocycle Design and Its Waveform-Generating Circuit for UWB Communications

Ultra-wide-band (UWB) technology can provide data throughput rate at gigabit per second. UWB also shows promising potentials for use in short-range indoor wireless communications and outdoor ad hoc networking. Adopting ultra-short impulses in UWB transmission, however, make systems vulnerable to timing jitter. To overcome this challenge, we propose a time-hopping high- order waveform modulation scheme in this paper. Central to our design is the adaptation of a high-order monocycle (HOM), which provides timing-jitter robust UWB communications. We present a CMOS pulse generator circuit to produce the HOM monocycle. We also use 0.18-mum CMOS technology with 1.8-V power supply to simulate the monocycle generator design using the Cadence software. The simulation results show that our generated waveform meets the UWB communication and the FCC requirements. Our modulation scheme outperforms other systems using traditional monocycles in terms of timing-jitter robustness.     

All-digital low-power CMOS pulse generator for UWB system

An all-digital CMOS ultra-wideband (UWB) pulse generator which complies with FCC regulations is presented. The proposed pulse generator generates a single UWB pulse satisfying FCC regulations without any filtering. The average power consumption of the whole circuit is 15.4 mW and 675 /spl mu/W at the pulse repetition frequency of 500 and 1 MHz, respectively.     

基于Hermite函数设计UWB脉冲的算法

由于UWB信号占据的带宽极宽,不可避免地重叠在现有窄带无线通信系统的频段上。为了不干扰其他窄带通信系统,UWB脉冲不仅应具有平坦的频谱且无直流分量,而且其频谱形状也必须满足相应的频谱规划,因此设计满足频谱要求的脉冲是UWB通信系统中一个至关重要的问题。研究了Hermite脉冲的特征,依据其特征提出设计UWB脉冲的算法,用这些脉冲可以构造一个M-ary通信系统。     

A new ultra-wideband, ultra-short monocycle pulse generator withreduced ringing

We introduce a new ultra-wideband (UWB), ultra-short, step recovery diode monocycle pulse generator. This pulse generator uses a simple RC high-pass filter as a differentiator to generate the monocycle pulse directly. The pulse-shaping network employs a resistive circuit to achieve UWB matching and substantial removal of the pulse ringing, and rectifying and switching diodes to further suppress the ringing. An ultra-short monocycle pulse of 300-ps pulse duration, -17-dB ringing level, and good symmetry has been demonstrated. Good agreement between the measured and calculated results was achieved     

基于认知无线电的脉冲陷波UWB窄带干扰抑制

提出了一种基于认知无线电的自适应超宽带(UWB)窄带干扰抑制方法.为了使UWB对变化的干扰环境具有自适应调节能力,引入了认知无线电技术.通过频谱感知和认知引擎技术提取窄带干扰频谱特征作为陷波器的设计依据.以高斯脉冲为例,对陷波器的陷波性能进行检验.最后,就陷波前、后脉冲的通信性能进行比较.仿真结果表明:认知陷波脉冲具有...