查询词典 frequency modulation

Laser technique ; modulation-free laser frequency locking ; acousto-optic modulation ; molecular absorption line

激光技术；无调制锁频；声光调制；分子吸收线

But, in the natural and artificial signal, a lot of signal phases don\'tvary linearly with time, for example, we usually use chirp signal in the radar technology,frequency step signal, linear modulation component of the ground echo in the SARtechnology, linear modulation component of the moving target echo, linear modulationcomponent while the airborn radar detecting the moving target, etc.

在自然界和人工信号中，许多信号的相位变化并不是随时间一次方变化，如雷达技术中常用的线性调频信号，频率步进信号，另外，SAR 技术中，地面回波所含有的线性调频分量，ISAR技术中，运动目标的回波所含有的线性调频分量，机载雷达探测运动目标时的线性调频分量，等等；傅里叶变换对此类信号分析所得的结果是信号在不同频率点上的能量分布，即信号在基函数上的投影。

It is a combination of the pulse amplitude modulation and frequency modulation types.

该仪器系统是由脉冲幅度调制和频率调制两种遥测系统复合组成的。

Frequency modulation minimizes noise and provides greater fidelity than amplitude modulation, which is the older method of broadcasting.

调频最大程度的减小噪音，并且比调幅的保真度高，调幅是一种较老的传播方法。

Based on surveying the development of variable frequency power supply and analyzing its development tendency, and considering the practical features of the assignment, the conversion system is designed as follows: it selects the 3-phase Pulse Width Modulation Engine SA4828 as the PWM control signals generator; it chooses the single-chip-computer PIC16F877 as the microcontroller, which integrated the A/D modulation, which cuts down the complexity of the hardware system and strengthens the dependability of the system.

在论述和分析了变频电源及其控制技术发展的概况和趋势的基础上，结合本课题任务的实际要求，设计了一套中小功率的逆变电源。系统中PWM控制信号采用专用集成芯片SA4828生成，减轻了控制器的工作量也提高了系统的可靠性。控制器选用集成了A/D转换器的单片机，使得系统的硬件复杂性降低，提高了可靠性。

Simulation results show that our algorithm enforces the adaptability of differential space-frequency modulation to the time delay expansion.Finally, we give our work to reduce the complexity of multiple symbol differential sphere decoding in differential space-time modulation. Through the modification of the enumeration strategy of the search tree in sphere decoding, we significantly reduce the complexity of detection at the expense of little loss on performance.

理论分析和仿真结果都验证了这种检测算法对长信道时延的适应能力论文最后还对差分空时调制中的多符号检测算法进行了研究，提出了一种降低差分空时调制系统中多符号差分球形译码算法复杂度的方法，通过改进球形译码中搜索树的排序策略，使得系统在牺牲较少性能的基础上大大降低了算法实现的复杂度。

Theoretical analysis of and experiments on the fundamentals, efficiency, cross-modulation, inter-modulation and spectrum analysis of multiple-frequency acousto-optic Bragg diffraction are made and its application in laser high-speed printer illustrated.

本文对多频声光布喇格衍射的原理、效率、交叉调制、互调制、频谱分析等进行理论分析和实验研究，并阐明其在激光高速印字机中的应用。

By means of a linear array CCD lightintensity distribution measuring system, via the variation of the frequency and the power of ultrasonic wave, the direction control and the intensity modulation for the laser beam can be carried out. The relation curve between acoustooptic deflexion and modulation measurement is given.

在实验中，应用线阵CCD光强分布测量仪等，通过改变超声波的频率和功率，分别实现了对激光束方向的控制和强度的调制；定量给出了声光偏转量的关系曲线和声光调制测量的关系曲线。

I introduced in the paper one kind of VVVF elevator control system, I has used the closed loop velocity modulation regarding the elevator velocity modulation system, and has carried on the detailed design separately to the hardware electric circuit main part,including PLC control section,frequency changer,main circuit and gate and so on.

在论文中我介绍了一种VVVF的电梯控制系统，对于电梯的调速系统我采用了闭环调速，并对硬件电路的主要部分分别进行了详细设计，包括PLC控制部分，变频器，主电路和门电路等。

At last, as two key parameters, the modulation index and modulation frequency are optimized.

最后还对调制中的两个关键参数调制指数和调制频率进行了优化分析。

Liapunov—Schmidt method is one of the most important method in the bifurcation theory.

Liapunov—Schmidt方法是分叉理论的最重要方法之一。

Be courteous -- even when people are most discourteous to you .

要有礼貌──即使当別人对你最不礼貌的时候。