查询词典 frequency modulation

Then three candidate modulation schemes exploiting spatial dimensions are proposed. At last, the three modulation schemes are compared by power efficiency and bandwidth efficiency. It shows that spatial quadrature amplitude modulation scheme is appropriate for long distance wireless optical communications for its high bandwidth efficiency and spatial circular symmetry.

参照传统时域信号设计方案，提出了三种空间调制信号具体设计方案，并从带宽效率和功率效率两性能上进行了比较，结果表明正交幅度调制具有带宽效率高、功率效率低的特点，而且采用的信号点越多其带宽效率就越高，另外其空间信号图案还具有圆对称性，因此非常适合在空间带宽有限的远距离无线光通信中使用。

The modulation function can be calculated by Fourier transform, filtering and inverse Fourier transform. The value of modulation function in areas of local shadow and abrupt discontinuities is lower than that in other parts. So modulation is a useful threshold to determine the quality of carrier stripe.

针对这种情况，本论文提出了通过傅立叶变换得到变形条纹图像的调制度函数，设置调制度函数阈值判断条纹质量的优劣，低于阈值的部分认为是不连续、阴影或陡峭区域，使用模板覆盖。

In the thesis, the space vector modulation of MC can be synthesized by fictitious rectifier and fictitious inverter. Two space vector control strategies of MC, which combines output line voltage space vector modulation and input phase current space vector modulation, is adopted.

本文采用输出线电压空间矢量调制和输入相电流空间矢量调制相结合的双空间矢量调制策略，对虚拟整流器和虚拟逆变器的空间矢量分别进行了分析，然后将二者综合得到矩阵变换器的调制方法。

"There are two different modulation methods commonly used to do this: pulse-code modulation, which is widely used for transmission in common-carrier communications; and delta modulation, which is finding broad application in military communications."

完成这一转换通常有两种调制方法：脉码调制，这种调制方法广泛用于普通通信传输中；增量调制，这种调制方法在军事通信中使用较多。

Multicarrier modulation in data transmission is discussed in the fourth chapter. The performance of MCM and single tone modulation over twisted pairs is compared. Discrete multitone modulation is used in ADSL system. A new variable constellation TCM method is proposed, It can adapt to the subchannel capacity automatically. The simulation results prove that this method is quite effective.

第四章讨论了多载波调制技术在数据传输中的应用，针对市话信道的具体传输环境，比较了单载波调制与多载波调制的性能；针对ADSL传输的目标，采用离散多频音DMT技术，独立提出一种新的星座图变化的格状码方案VCTCM，能动态地适应不同子信道的传输能力，给出的计算机仿真结果表明该方案有较好的效果。

The amount of pulse width modulation pulse generators of the proposed modulation strategy is only the half of that of the traditional modulation strategy, which is of significant theoretical and practical value for the digital implementation of cascade multilevel converter.

该策略较传统的载波相移SPWM可以节省一半的脉宽调制(pulse width modulation，PWM)脉冲发生器，对级联型多电平逆变器的数字化实现有重要的理论和实用价值。

The modulation that function of modulation of in-house AM, FM, PM, FSK makes the instrument can go to the lavatory is undee, and need not sole modulation source.

内部AM、FM、PM、FSK调制性能使仪器能够便利的调制波形，而无需零丁的调制源。

Simulation results show that, for the fixed sampling frequency, the error rises with the frequency increasing of periodic signal, and decreases with the attenuation time constant increasing of non-periodic signal. The sampling frequency determines the upper limit of appropriate frequency band directly. The research provides the basis for the selection of cutoff frequency in filter design.

仿真结果表明，在采样频率确定时，对于周期信号，计算误差随频率的增加而增大，而对于非周期信号，计算误差随衰减时间常数的增大而减小，采样频率大小决定了插值法用于分布参数模型的适用频带上限，该研究为滤波器设计中截止频率的选择提供了依据。

This experiment is in frequency adjustment X-mitter about that miniwatt frequency adjustment X-mitter operating principle, analyses the debugging making method and their installation, the microphone changes implication into an audible signal, wave an audible signal being modulated as a result of enlarging the day afer tomorrow being in progress to the carrier wave , producing frequency adjustment, by the fact that air wire launching the frequency adjustment electromagnetic wave to the outside , the radio set just can with frequency adjustment meet hear clear implication.

本毕业设计是关于小功率调频发射机工作原理、分析制作方法及其安装调试，在调频发射机中，话筒将话音转化为音频信号，音频信号经放大后对载波进行调制，产生调频波，通过天线向外发射调频电磁波，用调频收音机便可以接听到清楚的话音。

Two common methods of GPS signal coarse acquisition are analyzed and compared in this paper, and an optimized method is adopted. Two common algorithms of calculating fine frequency are analyzed and compared and the conics fitting is designed to calculate the fine frequency. Based on the distributing character of Doppler frequency shift, swing frequency style of Doppler frequency shift search is employed.

对比分析了两种常用的GPS信号粗捕获实现方法，设计了一种优化的实现方法；同时对常用的两种精细载波频率算法进行了比较分析，设计了一种二次曲线拟合的方法计算精细载波频率；基于多普勒频移的分布特点，改变以往顺序搜索的方式，采用跳频搜索的方法。

The production moved off-Broadway to New York City, where she won the Joseph E. Calloway award for her performance, and was profiled in American Theater Magazine as one of ten young theater artists to watch.

生产提出过百老汇的新的纽约市，在那里她赢得了约瑟夫calloway奖，她的表现，并于异型在美国的战区杂志之一， 10战区的青年艺术家观赏。

It's a risk tradeoff, and I believe that adding test support code usually wins.

这是一个风险的权衡，我相信添加测试代码通常会占上风。