基于NLTL的皮秒级快沿产生方法研究

分析了非线性传输线上升沿压缩原理与基本构成,研究了非线性元件与线性传输线相结合实现非线性传输线的可行性。从工程化设计角度,深入研究基于NLTL的皮秒级快沿的产生方法。给出了非线性元件参数、传输线参数与上升时间压缩参数之间的关系式,非线性传输线设计中参数的计算方法与过程。利用设计仿真验证了该方法的可行性,并通过实验电路测试探讨了工程化设计问题。     

利用高压探头和电阻分压器进行高压测量的性能比较

本文以电快速瞬变脉冲群发生器为例，针对电磁兼容研究领域中的高压脉冲瞬态信号的获取和测量问题展开了讨论。通过原理分析、实验结果比较，对电阻型高压分压器和高压探头这两种高压衰减器的频率响应特性进行了评估，确定了更加科学、准确、简便的高压脉冲瞬态信号的测量方法，并提出了测量过程中的注意事项，对于电磁兼容领域中各种脉冲干扰量的研究具有一定参考价值。     

快沿脉冲上升时间比对不确定度分析

本文首先介绍快沿脉冲上升时间的重要性,然后介绍能力比对的测量标准和测量方法,接下来进行不确定度分析,确定不确定度来源,详细介绍快沿脉冲上升时间的不确定度评定方法。     

应用于标准光电高温计的多点控温系统设计

为满足功率半导体器件参数测量中对脉冲高压源输出脉冲幅值和宽度的需求,基于Marx发生器原理设计了一脉冲幅值和宽度连续可调的脉冲高压源,用以对功率半导体器件参数的快速测量。该脉冲高压源通过改进Marx发生器基本结构,采用双电源充电模式,减小了脉冲发生器的充电时间;采用同步放电电路,提高了脉冲电压的输出精度;在此基础上,采用快恢复二极管隔离每级Marx电路,降低了充电损耗。通过控制双电源充电电压和放电回路中固态开关导通时间,实现了输出脉冲电压幅值和宽度连续可调。实验结果表明,该脉冲高压源在脉冲幅值0~8000 V和脉冲宽度200~1000 μs之间连续可调,上升时间为35 ns,可满足功率半导体器件参数快速测量的需求。     

FPGA超声相控阵高压发射精确延时设计

针对超声相控阵高压发射精确延时的关键技术,利用普通电压升压产生高压脉冲(负脉冲)发射,设计一种高压发射电路的精确延时电路.通过分析二极管高压钳位、相控阵发射聚焦、高压发射模块电路原理,应用FPGA软件聚焦方式改善发射电压、聚焦延时、上升脉冲等性能指标.FPGA仿真结果表明:钳位电路可对幅值为-100V的原始发射信号进行稳定钳位,发射脉冲上升时间＜10ns,可明显改善发射信号的精确性和准确度.     

一种用于示波器校准的快沿信号产生方法

提出了一种新的阶跃恢复二极管快沿的产生方法。利用肖特基二极管隔离直流偏置,采用电感阻止射频信号分流,串接电阻吸收反射改善快沿信号波形质量,而快沿标准化则决定于偏置电流与脉冲幅度的精度。设计了用于校准1GHz带宽示波器的快沿电路,获得80ps上升时间,验证了该方法的可行性。     

示波器上升时间计量的误差分析

上升时间是脉冲信号的一项重要参数,本文介绍了计量示波器上升时间测量误差产生的原因及解决方法。     

高电压脉冲校准装置研究

为解决高电压脉冲的校准问题,对高电压脉冲的校准方法进行研究,并建立了一套脉冲校准装置。校准装置将高电压脉冲信号进行电压转换,变为脉冲小电压,通过数据采集系统,在频带范围10Hz~1kHz、电压范围1~1600V内,对脉冲电压的关键参数进行测量,得到高电压脉冲的电压幅度、脉冲频率、脉冲宽度、上升时间和下降时间。通过实验室标准仪器设备对高电压脉冲校准装置进行测试,其中脉冲幅度的测量误差为 0.02%~0.4%。     

地方资讯

<正>市场监管总局批准建立脉冲波形参数副基准装置日前，市场监管总局批准建立脉冲波形参数副基准装置，该装置由北京无线电计量测试研究所建立，实现了3 ps上升时间的超快脉冲波形产生与测量，其关键核心部件完全自主可控。该装置的建立，为超高速通信、超宽带雷达探测、精密测量仪器研制等领域提供了具有国际先进水平的脉冲波形参数量值溯源源头。     

三角波信号波形参数的测量不确定度

通过使用波形测量手段和最小二乘直线拟合方法,对三角波信号的波峰、波谷、中值、幅度、频率、沿斜率、沿线性度、对称性等指标进行了精确评价,详细讨论了方法的实现过程以及有关技术问题,并对各项参数指标进行了不确定度分析。实验验证结果表明了该方法的有效性和实用性,该方法可应用到三角波信号源的性能指标评价中。     

High-Voltage Pulse Reflection-Type Attenuators with Subnanosecond Response

Significant advances have been achieved in high-voltage pulse attenuation and measurement fidelity by utilizing the principle of traveling-wave reflection at an abrupt impedance mismatch along a transmission line. Such "reflection-type" attenuators allow practically distortionless attenuation of the signal, independent of voltage level. Their rise-time response and attenuation factor can be known very accurately because they are free from voltage and temperature effects making them especially suited as high-voltage pulse calibration standards. The rise-time response for such attenuators can readily attain 100 ps or less, a practical limit being about 30 ps.     

不同应力波穿过多条非线性变形节理时的透射特性

基于节理非线性位移不连续模型,分析不同弹性纵波正向入射多条节理时的透射规律。利用半解析半数值解法得到透射初至波质点振动速度一维数值差分解,进而研究不同类型、不同振幅的入射纵波穿过多条节理时,初至波质点速度幅值、能量、频谱及时间延迟的变化特性。研究表明,透射能力由大到小的顺序为:矩形波、半正弦波、三角形波。速度透射系数、能量透射系数、透射波中高谐波频域幅值均随入射脉冲幅值增大而增大;延迟时间随入射波振幅的增大而减小,且三角波入射时的时间延迟大于半正弦波。随着节理条数的增加,速度和能量透射系数逐渐降低,且下降速度逐渐减慢;高谐波频域幅值先增大后下降,且下降速度逐渐减慢;时间延迟增大的速度逐渐加快。     

Shaping Fast Rise-Time Pulses with Tapered Transmission Lines

For the purpose of checking very fast time-domain reflectometer (TDR) systems it is desirable to have a fast rise-time pulse whose parameters are known. A means for obtaining pulses meeting these requirements has been achieved by suitably tapering the inner conductor of a rigid coaxial transmission line having air dielectric, commonly referred to as an air line. The air line is driven with a pulse that has a very fast rise time compared to the rise time of the expected output pulse. A reflected pulse will be generated whose shape is dependent upon the taper of the inner conductor. A procedure is outlined for determining the proper taper to shape the leading edge of the reflected pulse to match any continuous single-valued function. Air lines that were designed and built for producing a pulse whose leading edge is a linear ramp, a truncated Gaussian function, and the integral of a truncated Gaussian function are discussed and traces of these pulses are shown. The problem of re-reflections due to the multiple discontinuities along the air line was analyzed by means of a computer. This program is described. The effect of the driving-pulse parameters on the reflected pulse is analyzed on a theoretical basis. Rise time, pulse shape, and aberrations such as overshoot and ringing of the driving pulse are considered in this analysis.     

Measurements and calculation for magnetically coated strip transmission lines

Measurement of the transmission parameters of magnetically coated strip conductors over a ground plane show that the series componentsRandLvary rapidly with frequency. If these components are resolved into an alternative configuration consisting of a parallel and series arrangement, this frequency variation is almost entirely absent. Calculation of the pulse transmission properties is then made much simpler. Comparison between calculated and measured waveforms is illustrated. The alternative circuit also suggests a line termination consisting of a resistance and capacitance which, both calculation and observation confirm, leads to good rise-time and pulse amplitude maintenance.     

光电脉搏波信号处理中呼吸干扰的抑制

动态光谱的检测精度与光电脉搏波的幅值检测精度直接相关．为了获取较高的幅值检测精度,抑制光电脉搏波中的呼吸干扰,采用基于相干平均的脉搏波特征参数重构滤波和小波变换相结合的方法对光电脉搏波原始测量信号进行处理．首先用相干平均法获取脉搏波特征参数并重构光电脉搏波信号;然后对原始信号减去光电脉搏波后的剩余部分进行小波频率分析,并提取呼吸干扰,处理结果表明,本文的方法可以提取到高精度的光电脉搏波幅值信息,抑制大部分的呼吸干扰,从而改善动态光谱的检测精度．     

A Gigawatt High-Voltage Generator for Coherent Soft X-Ray Generation

A fast gigawatt high-voltage generator was developed to drive an argon-filled capillary for the generation of pulses of coherent short wavelength radiation in the extreme ultraviolet and soft X-ray region. A four-stage double Marx bank that is capable of delivering voltage pulses of 150 to 350 kV at 290-ns transition duration was used to pulse charge a 5-Omega-impedance water-filled pulse-forming line. A fast current pulse with amplitude ranging from 9 to 21 kA and 35-ns transition duration was generated through a 20-cm-long and 3-mm-diameter alumina channel filled with argon. Laser emissions in the Ne-like Ar at 46.9 nm have been observed in the pressure range of 0.14-0.38 mbar. It was also observed that over the spectral range from 20 to 70 nm, no other transitions, except the 46.9-nm line, experienced high gain and strong amplification.     

宽带信号检测中自适应门限设定方法

在水声定位中,常常需要估计声波从发射端到接收端的传输时间。但由于传输距离的影响,接收到的声波信号强度变化范围很大,给检测带来不便。基于线性调频脉冲信号相关检测,提出了一种自适应门限设定方法,可以在一定的条件下替代自动增益控制电路。这一方法根据发射信号、传输信道、发射系统和接收系统的参数,依据声信号到达接收端的时刻,自动调整相关峰检测时的门限值,简便易行。仿真和湖上试验结果表明,这一方法可以有效地保证计算信号到达时刻的准确性。     

Force sensors based on distortion in delay lines

The principle of operation of force sensors based on distortion in delay lines type of sensor is the distortion of an acoustic signal, in a pulse-excited magnetostrictive delay line due to a force applied at any point between the point where the pulse is generated and the receiving coil. A conductor orthogonal to the delay line is used for pulsed current transmission and its distance is fixed with respect to the delay line. The input and the output of the system are the applied force on the delay line support and the amplitude of the detected output V _o, respectively. Under fixed amplitude of the pulsed current, V_o has a maximum value under zero input and decreases as the applied force increases. Experimental results show that the response of the sensor is a monotonic, exponential function of the applied force. A method is also proposed, according to which an integrated sensor array could be made based on this principle     

Resonance S-band relativistic backward wave oscillator based on a submicrosecond pulsed high-voltage generator

We present the results of investigations of a resonance S-band relativistic backward wave oscillator (RBWO) that employs a submicrosecond pulsed high-voltage source based on a Marx generator scheme with a water-filled pulse-forming line. It is shown that the spontaneous limitation of the microwave pulse duration in the RBWO is caused by the emission of charged particles from plasma generated at the surface of a slow-wave system under the action of intense high-frequency fields. An increase in the electric strength of the electrodynamic system of the resonance RBWO, which was achieved by processing the surface with a high-current low-energy electron beam, allowed the pulse energy to be increased to 250 J at a peak output radiation power of about 3 GW.