查询词典 modulation

The results show that injection locking synchronization is realized when injection rate is large enough. In the injection locking regime, similarity index is larger for external modulation than that for direct modulation. If injection rate keeps unchanged, synchronization is little affected by modulation index, but it is affected by modulation frequency. Since outputs of the master laser are antiphase for direct modulation and external modulation, the fluctuations of similarity index with modulation frequency for the two lasers are contrary.

研究结果表明：当注入强度足够大时，系统实现注入锁定同步，外部调制的相似指数大于内部调制；注入强度恒定时，同步品质几乎不受调制指数的影响，而受调制频率的影响；由于内部、外部调制引起主激光器的输出反相，两种调制方式下同步品质随调制频率的变化趋势也相反。

The noise frequency modulation signal was particularly analyzed. The Fokker-Planck equation of noise frequency modulation was presented and the Motion-Group Fourier Transform was used by converting the partial differential equation into the variable coefficient homogenous linear differential equations. Then the solutions were given by using the peano-baker series. So the probability density function of noise frequency modulation in the filter was given. On the basis of the probability density function the stochastic resonance of noise frequency modulation signal is analyzed.

首先建立了噪声调频干扰信号通过脉冲压缩雷达中频滤波器后所满足的福克尔－普朗克方程，然后利用群移傅立叶变换（Motion-Group Fourier Transform，MGFT）将此偏微分方程化成了变系数齐次线性微分方程组，并利用Peano-Baker级数法给出了该方程组的解，最后得到了噪声调频干扰信号通过脉冲压缩雷达中频滤波器后的概率密度函数，在此基础上研究了噪声调频干扰信号造成的随机共振现象。

A design and implementation method of the high speed modulation system, which adopted the new techniques of the FPGA and DAC based communication system,is presented in this paper. The effect of the key techniques of this system, such as the high speed digital signal processing for modulation, high speed based-band signal conversion, wide-band modulation, carrier suppression, high frequency and high precision system clock generation, is analyzed, and the solutions and performance analysis is also given. Finally, a high speed modulation system for space applications is implemented, can be used for high speed data transmission with QPSK, 8PSK, QAM or other kinds of digital modulation.

本论文依据正交调制原理，采用基于FPGA和DAC的设计技术，提出了一种高速、灵活的调制系统的设计方法，重点分析了系统组成的调制编码映射、基带脉冲信号转换、信号滤波、调制、系统时钟产生等关键技术环节的影响，解决了高速调制信号处理、高速数据转换、宽带调制、载波抑制、高频率高精度系统时钟的产生等关键技术问题，完成了一种适用于空间应用的高传输速率、多进制数字调制方式和调制体制灵活的数据传输调制系统的设计与实现，可在硬件设计不变的情况下，实现QPSK、8PSK和16QAM等多种调制方式的高速数据传输，QPSK调制速率达到500Mbps。

modulation is the transmission of information to be loaded onto a high-frequency signal in the process.amplitude modulation using signal to control the rate of carrier,with its linear modulation signal changes,and maintain the same carrier frequency.in the amplitude modulation,in accordance with the strength of signals in the spectrum of different components,it is divided into ordinary am (amplitude modulation standard am),with inhibition of bilateral carrier am,the carrier single sideband suppression am.the main difference is the different methods and structure of the spectrum.

摘 要：调制是将要传送的信息装载到某一高频信号上去的过程。振幅调制是用调制信号去控制载波的幅度，使其随调制信号线性变化，而保持载波的频率不变。在幅度调制中，根据已调信号的频谱分量不同，分为普通调幅、抑制载波的双边带调幅、抑制载波的单边带调幅。它们的主要区别是产生的方法和频谱结构不同。

The article presents the developing condition of PWM and SVPWM first.Then the theory of SVPWM is discussed in detail.The SVPWM is based on the thought of magnetic chain tracking.It makes the ideal magnetic chain circle of three-phased sysmmetry electric motor supplied by three-phased sysmmetry sine wave voltage for basis,uses the practical magnetic chain vector formed by the different switch modes of three-phased inverter to track the basic magnetic chain circle.During the course of tracking,the inverter changes the switch modes properly to form the PWM waves.Then the modulation wave of SVPWM is analyzed in detail.The modulation wave of SVPWM is implicit,but the analogous modulation wave in A-B-C axis needs to be calculated in order to expose the internal relation of SVPWM and SPWM.That is to show the implicit modulation wave of SVPWM. SVPWM actually is a transformed SPWM ruly sampled by the modulation wave which is injected by the zero prefaces based on space vectors.

本文首先对脉宽调制技术的发展现状进行了综述，在此基础上分析了电压空间矢量脉宽调制技术的发展现状；接着对空间电压矢量脉宽调制技术的基本原理进行了详细的分析和推导，SVPWM是基于磁链追踪的思想，它以三相对称正弦波电压供电下三相对称电动机定子理想磁链圆为基准，由三相逆变器不同开关模式下所形成的实际磁链矢量来追踪基准磁链圆的，在追踪的过程中，逆变器的开关模式作适当的切换，从而形成PWM波；然后详细分析了电压空间矢量脉宽调制技术的调制波，虽然SVPWM法的调制波是隐含的，但是为了揭示SVPWM法与SPWM法的内在联系，需要求出SVPWM在A-B-C坐标系上的等效调制波，也就是将SVPWM的隐含调制波显化；SVPWM实质是一种基于空间矢量在三相正弦波中注入了零序分量的调制波进行规则采样的一种变形SPWM。

This paper discusses the pulse-width modulation switch sequence of arbitrary-number-level inverters, and proposes a switch sequence with loss balance of power electronic devices.

讨论任意电平逆变器脉宽调制(pulse-width modulation，PWM)序列，提出一种电力电子器件损耗均匀分配的序列方式。

Common AM, with bilateral, residual sideband and single sideband modulation, and so is the amplitude modulation of a few typical examples, and frequency modulation modulation in the point of view is widely used.

常见的调幅、双边带、残留边带和单边带等调制就是幅度调制的几个典型实例；而频率调制就是角度调制中被广泛采用的一种。

Modulation of the online system, the text will be AM, with bilateral and single sideband for that object, from the basic principles, and other aspects of analysis and simulation analysis on while in nonlinear Modulation, as commonly used FM and Phase Modulation for that target on its modulation principle, for example simulation and analysis.

在线性调制系统中，文中将以调幅、双边带和单边带为说明对象，从原理等方面进行分析阐述并进行仿真分析；而在非线性调制中，以常用的调频和调相为说明对象，说明其调制原理，并进行举例仿真分析。

It is pointed out that conventional trailing-edge modulation, leading-edge modulation and STT modulation are special cases of ATT modulation.

分析结果表明，传统的后缘调制、前缘调制以及STT调制都是ATT调制的特殊情况。

In order to bring about the spatial depth resolution of the image data obtained, the method according to the invention comprises the following steps: an electromagnetic wave is beamed onto the surface of a photonic mixed element comprising at least one pixel, the pixel having at least two light-sensitive modulation light gates Gam and Gbm and associated accumulation gates Ga and Gb; modulation light gate voltages Uam and Ubm, which are configured as Uam=Uo Um and Ubm=Uo-Um, are applied to the modulation light gates Gam and Gbm; a direct voltage, whose magnitude is at least the same as that of the total of Uo and the amplitude of the modulation voltage Um, is applied to the accumulation gates Ga and Gb; the charge carriers produced in the space charge region of the modulation light gates Gam and Gbm by the incident electromagnetic wave are subjected, as a function of the polarity of the modulation light gate voltages Uam and Ubm, to the potential gradient of a drift field and drift to the corresponding accumulation gate Ga or Gb; and the charges qa and qb which have drifted to the accumulation gates Ga and Gb, respectively, are diverted.

为了使得采用这样一种方法获得的图象数据具有空间深度分辨率，按照本发明的方法包含下述步骤：使电磁波成束在至少包含一个象素的光混合元件的表面上，该象素至少具有两个光敏调制光门G am 和G bm 以及相关的累积门G a 和G b ；将调制光门电压U am 和U bm 施加到调制光门G a 和G b 上，而调制光门电压的构成是U am=U o U m，U bm=U o -U m；将直流电压施加到累积门G a 和G b 上，而直流电压的幅度至少与U o 和调制电压U am的幅度的总和相同；使由入射电磁波在调制光门G am 和G bm 的空间电荷区中产生的载流子经受漂移场的电位梯度，并漂移到相应的累积门G a 或G b ，而电磁波是调制光门电压U am和U bm的极性的函数；已经分别漂移到累积门G a 和G b 的电荷的方向反向。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。