查询词典 frequency modulation

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。

This article introduced the elevator velocity modulation is carries on the velocity modulation through the frequency conversion.

本文介绍的电梯的调速是通过变频来进行调速的。

Its output current can be continuously adjusted from zero to two hundred milliamperes and its stability reaches 1.5×10-5. The variation of the output current is less than 1μA when its operation time is longer than 12h. The modulation of frequency and intensity of optical wave in the laser interferometry can be achieved by the modulated current (100kHz～300kHz) input, whose modulation depth is continuously adjustable from zero to one hundred milliampere.

该电路的直流稳定度高达1.5×10-5，输出电流在0～200mA内连续可调，长时间工作（12h以上）电流变化小于1μA；在直流基础上注入100kHz～300kHz的调制电流，其调制深度为0～100mA连续可调，可实现在激光干涉测量中对光波频率和光波强度的调制。

Based on radar backscatter theory and scatter point model,aimed at the same frequency vibration scatter point of radar target,radar echo universal model is derived and the periodicity of amplitude modulation function and phase modulation function is researched at length.

基于雷达后向散射理论和散射点模型，针对雷达目标的同频振动散射点，详细推导并建立了雷达回波通用模型，对其幅度调制函数和相位调制函数的周期性进行了详细的讨论。

At last,simulation research is carried out on radar echo of two same frequency vibration scatter points.Theoretical annlysis and simulation result indicate that the model is effective and that the periodicity of amplitude modulation function and phase modulation function is invariable as the number of scatter points increased,but,their amplitudes are variational.

最后对两个同频振动散射点合成雷达回波进行了计算机仿真研究，理论分析和仿真结果表明，该模型是有效的，并且随着同频振动散射点数的增加，其幅度调制函数和相位调制函数的周期性不发生变化，只是它们的值会随着振动点数的增加而改变。

This article introduces the technology of the soft starter for belt conveyor,and compares the working principles,advantages and disadvantages of velocity modulated hydraulic coupler ,liquid sliminess soft starter,CST,frequency conversion velocity modulation soft starter,silicon-controlled velocity modulation soft starter.

介绍了带式输送机软起动技术现状，比较了调速型液力偶合器、液体粘性软起动、CST，可控硅调压调速、变频调速技术等软起动技术的工作原理及优、缺点，展望了其发展趋势，对带式输送机系统中软起动装置的选用有一定的参考价值。

Wavelet packet based multicarrier modulation is a technique combining wavelet analysis theory and multicarrier modulation perfectly. It provides high frequency efficiency, better performance against intersymbol interference, intercarrier interference, tone and impulse interference and can transmit multirate symbols easily.

小波包多载波调制技术是一种新兴的多载波调制技术，是小波分析理论和多载波通信的完美结合，具有频谱利用率高和良好的抗符号间串扰、信道间干扰、脉冲干扰和单频干扰的优良特性，并且易于多速率传输。

The numerical results of the dispersion relation show some nonlinear effects: for a fixed geometry of a waveguid, beam parameters and plasma density, the increment of the modulation parameter may lead to a slight increment of the operating frequency, However, as the modulation parameter increases further, saturation may occur and the dispersion relations are hard to be separated, it is due to the overmodulation of the microwave power, this phenomenon itself belongs to the nonlinear effects.

五。用严格的场匹配方法分析了填充等离子体的耦合腔链，研究了等离子体一腔模的形成以及&冷&带宽和&热&带宽的展宽效应。等离子体填周期性耦合腔(来源：Aae53d3BC论文网www.abclunwen.com)链后，形成周期性的截止频率为0的等离子体TG模式。如果填充的等离子体密度较低时，腔模和槽模的工作频率均有小幅上升，而带宽改善不明显。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。