脉冲宽度

The performance of 2-level pulse amplitude modulation and analogue pulse width modulation system based on self-error-correction code was analyzed.

基于自纠错码的二级脉冲幅度调制与脉冲宽度调制光纤传输技术，对系统中的接收机灵敏度进行了分析。

The principle is using thefast breakover of avalanche transistor drive the electron tube. The full time of 4200Vvoltage is about 20ns. The circuit can normally work under 100kHz frequencies.Design an extra fast Q-switch circuit by series arrangement of avalanche transistor.

本论文主要做了以下几方面工作：1、推导了重复率激光基本参数(脉冲能量、脉冲宽度和峰值功率)与周期的关系，并且分析了重复率激光系统运转的稳定性。2、设计了雪崩管-电子管退压电路，由雪崩管驱动电子管开关，4200V高压退压沿20ns左右，能够在100kHz频率下工作。

In this dissertation, some research on the contact reliability of relay has been made on the basis of a new measuring method for contact resistance that is the pulse current method. The thermal propagation has been analyzed so as to analyze the thermal effect of pulse current flowing over contact.

本文在提出一种新的测量接触电阻方法——脉冲电流法（脉冲宽度为300μS）的基础上，针对继电器接触可靠性进行了研究，并对触点热过程进行了分析，以便分析脉冲电流对触点产生的热效应。

In recent years, cold cathode thyratron KN-22 is widely used in circuit, but here KN-22 is replaced by MOSFET. The circuit with MOSFET has stable and credible performance, it can output a pulse of -6.6～-8kV and the pulse width can be adjusted from 5ns to 10ns.

应用冷阴极闸流管KN-22作为开关线路比较广泛，但近年来我们改用MOS场效应管线路代替KN-22，该线路性能稳定可靠，输出脉冲幅度为-6.6～-8kV，脉冲宽度5～10ns可调，触发晃动小于0.5ns，触发延时30～40ns，单脉冲选出率为100%。

The result indicate that: the electrodeposition of zinc on nickel and tungsten substrates involves instantaneous three-dimensional nucleation. The coating is the best when the current density is 4mA/cm2 and the temperature is 80 ℃. The coating by the method of the impulse electrodeposition is better than the direct current electrodeposition. Especially when f is 100Hz, ton/toff is 2/8 and J is 8mA/cm2, the coating is clean and uniformity. The crystal size is nearly 0.3μ m .

结果表明：阴极反应为准可逆反应，锌离子在镍电极和钨电极上形核是三维瞬时形核半球形扩散长大过程，直流电流密度为4mA/cm2，温度为80 ℃时，镀层质量最好；脉冲电沉积得到的镀层要优于直流电沉积得到的镀层，尤其在脉冲宽度为2ms，脉冲间隔为8ms，电流密度为8mA/cm2时，得到的镀层光滑而均匀，颗粒大小接近0.3μm。

Experiment result indicates that laser power density,welding speed,pulse frequency and pulse width are the key factors of pulse laser welding and that the polishment,close touch of butt joint faces have an important effect on the air vents number in welding line and the mechanical performance of welding line.

实验结果表明：对焊面的打磨、抛光和紧密接触对防止焊缝中产生过多的气孔和提高焊缝的机械性能有重要作用；激光功率密度、焊接速度、脉冲宽度和脉冲频率四个参数是实现脉冲激光焊接的关键因素。

First, the effects of magnetic RAM relaxation time and the rise-time of incident pulse signal on reflection signal are discussed, the relationship between the rise-time of incident pulse and relaxation time based on the energy of reflection signal is revealed. Then, the effects of magnetic hysteric, susceptibilities and saturation upon reflection signal are analyzed, the results reveal the reflection of RAM target and UWB signal design. In the meantime, dielectric relaxation time effect about dielectric RAM target is analyzed simply, and the effects of relaxation time and the width of incident pulse upon reflection signal are probed. Finally, a few RAM targets are measured in the chamber using the impulse radar experiment system which is developed by the team of anti-stealth impulse radar on Department of Electrical Engineering, National University of Defense Technology. The experimental results show the similarity of the rule of echos with the theory. From the compared results of different tagets, we concluded, compared with 15% wideband sinusoidal signal, the impulse signal has increased 10～12dB energy from the same loaded RAM target; this, in turn, shows the nonlinear effects of RAM to the echoes, and the potentiality of the impulse signal to RAM targets.

首先分析了磁性RAM的弛豫时间及入射脉冲信号的上升时间对反射信号的影响，从反射信号能量角度出发，给出了入射脉冲上升时间与弛豫时间的关系；接着分析了磁性RAM的磁滞特性、磁化率及磁化强度对反射信号的影响，给出了RAM目标辐射和有关UWB信号设计的一般性结论；其次，对介电RAM的弛豫时间效应作了简单的分析，探讨了介电弛豫时间及入射脉冲宽度对反射信号的影响；最后利用国防科技大学电子技术系&反隐身冲激雷达技术研究组&研制的冲激雷达实验系统，在微波暗室中对几种不同的RAM目标进行了测量，结果表明：其反射波形的基本规律与上述理论分析相一致；从各种不同目标回波的能量对比结果得出，涂覆RAM目标对冲激信号的吸收比15％带宽的正弦信号要小10～12dB，证实了RAM的非线性效应对回波的影响，也证实了冲激信号反隐身的潜力。

The most common form of UWB is Impulse Radio,which communicates using very short pulses,typically on the order of hundreds of picoseconds.

脉冲无线电是超宽带的最主要形式，它使用脉冲宽度级数为几百皮秒的短脉冲进行通信。

The transit time and gain characteristics of electrons which travel in the micro-channel plate gated by picoseconds high voltage pulse were simulated.

对皮秒高压脉冲驱动下微通道板中电子的渡越时间特性和增益特性进行了数值模拟，在电压脉冲波形分别为高斯形、三角形和梯形时，得到了电子渡越时间与电压脉冲宽度、幅度的关系曲线。

The transit time and gain characteristics of electrons which travel in the micro-channel plate gated by picoseconds high voltage pulse were simulated. The curves of the transit time versus the voltage pulse width and the voltage amplitude are obtained when the waveforms of the voltage pulse are Gauss, triangle and trapezoid.

对皮秒高压脉冲驱动下微通道板中电子的渡越时间特性和增益特性进行了数值模拟，在电压脉冲波形分别为高斯形、三角形和梯形时，得到了电子渡越时间与电压脉冲宽度、幅度的关系曲线。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。