查询词典 pulse amplitude modulation

Third, it has a discussion on the development of modern and traditional artificial neural network technology and their application in image processing. It summaries that the model of the Pulse-coupled neural network based on Elkhorn's model of the cat visual cortex was constructed according to the mammalian vision systems. The nonlinear modulation property, which is a generic and pervasive biological pulse-coupling mechanism, is used in the construction of PCNN. So, PCNN finds many applications in image processing, including segmentation, edge extraction et al. As all known, the performance of the image segmentation depends not only directly on the adjustment of PCNN parameters and the statistical properties of image but also on the cyclic iteration times N of PCNN. If the parameters have been properly set, it turns out to be essential to select a suitable criterion to determine N.

回顾了神经网络技术的现状，指出传统人工神经网络只利用了生物神经元有限的属性进行模型构建，而90年代产生的脉冲耦合神经网络充分利用了哺乳动物视神经网络特有属性，其神经元模型除了考虑生物神经元特有的线性相加、兴奋与抑制属性外，还考虑到生物神经元特有的非线性相乘调制耦合特性；考虑了哺乳动物视神经系统视野受到适当刺激时，相邻连接神经元同步激发产生35Hz～70Hz振荡脉冲串特性等，所以PCNN网络模型更靠近真实生物视觉特性，特别是哺乳动物视神经网络，特别适合计算机图像处理应用，尤其在生物细胞图像分割、图像平滑、降噪及图像中目标的分类、计数等方面的研究。

Single-phase Sinusoidal Pulse Width Modulation Inverter Power Supply in this paper belongs to AC power supply (AC-DC-AC convert). Control mode adopts feedback of voltage control. The methods of intermitting power flux and changing duty-cycle can change pulse width of drive voltage that adjust and rectify output voltage ultimately.

本文设计的单相脉宽调制逆变电源属于交流电源，采用电压反馈控制，通过中断功率通量和调节占空比的方法来改变驱动电压脉冲宽度来调整和稳定输出电压。

At first, this paper gives the brief introduction of the history and present status of accelerometer and its testing technology, the working principium and math model of the liquid floated pendu-lous accelerometer, and then, decides the binary width pulse force retrim loop as the design proposal of testing system, researches the transfer function of every part in the system emphasizly, analyses the stability of the whole accelerometer testing system from the angle of control theoretics by the open loop transfer function of system, and designed the correcting net, analyses the basal problems such as resolution, sampling restraint, precision and so on, designs the hardware testing circuits such as preamplification, band-pass filter, alternating amplifier, phase sensitive demodulatorn, pulse-width modulation, frequency scale circuit, moment current generator. Finally, using the graphics program language LabV-IEW which is designed for testing field especially by NI accomplishes the solfware design of testing system,realized the testing functions.

首先对加速度计及其测试技术的发展历史和现状，液浮摆式加速度计的工作原理和数学模型等作了简要的介绍，然后确定了以二元调宽脉冲再平衡测试回路为设计方案，并从控制理论的角度进行了分析，着重研究了系统中各部分的传递函数，利用系统开环传递函数分析了系统的稳定性，同时设计了系统的校正网络；分析了二元调宽脉冲再平衡测试回路的分辨率、采样约束以及测试精度等基本问题，并按照系统分析的结果设计了包括前置放大、带通滤波、交流放大、相敏解调、脉宽调制、频标电路以及力矩电流发生器等测试系统各部分硬件电路，验证了电路的正确性，最后按照测试系统的要求，采用了美国NI公司专为测试领域所开发的虚拟仪器工具——LabVIEW作为测试软件开发工具，利用该图形化编程语言完成了测试系统软件部分的设计，实现了测试功能。

The double～probe pulse echo method, combining the advantages of transmission technique and pulse reflection method, is used to optimize the ultrasonic echo signal amplitude in case of strong attenuation of energy when ultrasonic signal transmitting in solid rocket motor grain.

采用双探头脉冲反射法，综合了穿透法和脉冲反射法的优点，实现了超声信号在固体火箭发动机药柱中传播时能量强衰减的情况下超声回波信号幅值的最优化。

A bipolar pulse gener AT or with A valanche Transistor is introduced which uses two paralleled tubes to enhance the amplitude of the output pulse. Meanwhile the power supply voltage can be adjusted, so better synchronous triggering can be performed.

介绍了一种双极性雪崩三极管脉冲产生器电路；电路采用双管并联以增大输出脉冲的幅度，并采用调节电源电压的方法来达到良好的同步触发。

Using the combination of Gaussian monocycles pulse with different amplitude and different delay,a new ultra-wideband pulse design algorithm for Inband interference suppression is presented.

采用不同幅度和延迟的高斯函数脉冲组合来拟合抽样函数脉冲，利用拟合的抽样函数脉冲设计超宽带脉冲信号，实现美国联邦通信委员会制定的辐射掩蔽要求的高效逼近。

When the numbers of high - amplitude pulse were among 1-3 pulses, the relationship between the number of pulse and MPF of click song was approximately linear, otherwise was nonlinear.2、 The bandwidths of the song were nearly 2700 - 6700Hz when the songs were produced by a pair of tymbals.

本文进一步阐明：1、高幅值PT多含有11个脉冲，当含有1，2，3个时，脉冲个数与MPF成准线性关系超过三个为非线性关系。2、双发声膜发声的频带主要在2700Hz-6700Hz之间。

The third, fifth and seventh harmonics were selected to calculate the pulse width jitter, and the corresponding product of pulse width and angular frequency, 7W, were 1.305, 2.175 and 3.045, respectively. With 25 kHz～5 MHz integration limits, the pulse width jitter was obtained to be 3.08ps.

选择脉冲重复频率的三次、五次和七次谐波的功率谱进行分析，三个谐波级次对应的脉冲宽度角频率积Tω分别为1.305，2.175和3.045，在25 kHz～5 MHz偏移频率范围内，得到的脉冲宽度抖动为3.08ps。

The information of bore-hole inclination measured by the downhole apparatus is transferred to the pulse signal generator , and then sent to the pressure sensor on the stand in a form of pressure pulse and recorded by the electronic recorder finally the drift angle is indicated according to the pulse signal .

其工作原理为：通过精密的测量机构测量井斜，测得的井斜信息由控制机构传递给脉冲信号发生装置，该装置发出的信号通过钻井液以压力脉冲的形式传递给立管上的压力传感器，接收的信号由电子记录仪记录，由记录的脉冲信号读出井斜角。

It not only records the number of input clock pulse, but also realize frequency, timing, producing beats, such as pulse and pulse sequence.

它不仅能记录输入时钟脉冲的个数，还可以实现分频、定时、产生节拍脉冲和脉冲序列等。

Diabetes is a social disease that affects several million people worldwide.

糖尿病是一个社会性疾病，全世界有数百万人罹患此病。

I'll call you on Friday to see if we can reschedule our luncheon meeting at your convenience.

我星期五会给您打电话在您方便的时候我们重新安排我们的午餐约会。