查询词典 frequency modulation

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。

The sending end when the use of pulse modulation approach will be a binary digital signal into a frequency modulation of the pulse sequence, and driver fired infrared tube to the form of light pulses sent receiver will receive the pulse of light conversion to electrical signals , and then, after amplification, filtering and other treatment to the demodulation circuit after demodulation, reduced to a binary digital signal after the output.

发送端采用脉时调制方式，将二进制数字信号调制成某一频率的脉冲序列，并驱动红外发射管以光脉冲的形式发送出去；接收端将接收到的光脉转换成电信号，再经过放大、滤波等处理后送给解调电路进行解调，还原为二进制数字信号后输出。

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。

Differential modulation is also a widely used method to the case of no knowledge of the channels in the receiver. Here we propose noncoherent sequence detection for differential space-frequency modulation, which can be used to alleviate the error floor that occurs in a multipath channel with long time delay expansion.

在接收端不知道信道状态信息的情况下，差分调制也是一种被广泛采用的技术，论文提出了应用于差分空频调制的非相干序列检测方法，该方法通过积累多个符号上的信道信息来完成发送符号的检测，可以消除由于长的信道延迟扩展带来的误码平层。

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。

As thebiggest hydropower station of two-row placed units in the world, LijiaxiaHydropower Stationinstalled capacity 1600(4×400MWof Yellow River upstreamis the chief station for hump modulation and frequency modulation in northwest area.

李家峡水电站是目前世界上最大的双排机水电站，装机1600(4×400)MW，是西北电网中的骨干调频、调峰电厂。

Salt is good, but if the salt becomes flat and tasteless, with what do you season it?

14：33 盐本是好的，盐若失了味，可用什么叫它再咸呢？

He reiterated that the PLA is an army of the people under the leadership of the Communist Party of China.

他重申，人民解放军是在中国共产党领导下的人民军队。