查询词典 frequency modulation

By a voltage-traced SPWM technology, the sine pulse width modulation wave was derived and the project of voltage output was designed. Resultantly, the microcontroller was fully used in the variable-frequency power system.

讨论了系统的硬件、软件设计和正弦脉宽调制波的生成和输出稳压方案的设计，采用了实时电压跟踪SPWM技术，使单片机在变频电源系统中得到了有效的应用。

At first, this paper gives the brief introduction of the history and present status of accelerometer and its testing technology, the working principium and math model of the liquid floated pendu-lous accelerometer, and then, decides the binary width pulse force retrim loop as the design proposal of testing system, researches the transfer function of every part in the system emphasizly, analyses the stability of the whole accelerometer testing system from the angle of control theoretics by the open loop transfer function of system, and designed the correcting net, analyses the basal problems such as resolution, sampling restraint, precision and so on, designs the hardware testing circuits such as preamplification, band-pass filter, alternating amplifier, phase sensitive demodulatorn, pulse-width modulation, frequency scale circuit, moment current generator. Finally, using the graphics program language LabV-IEW which is designed for testing field especially by NI accomplishes the solfware design of testing system,realized the testing functions.

首先对加速度计及其测试技术的发展历史和现状，液浮摆式加速度计的工作原理和数学模型等作了简要的介绍，然后确定了以二元调宽脉冲再平衡测试回路为设计方案，并从控制理论的角度进行了分析，着重研究了系统中各部分的传递函数，利用系统开环传递函数分析了系统的稳定性，同时设计了系统的校正网络；分析了二元调宽脉冲再平衡测试回路的分辨率、采样约束以及测试精度等基本问题，并按照系统分析的结果设计了包括前置放大、带通滤波、交流放大、相敏解调、脉宽调制、频标电路以及力矩电流发生器等测试系统各部分硬件电路，验证了电路的正确性，最后按照测试系统的要求，采用了美国NI公司专为测试领域所开发的虚拟仪器工具——LabVIEW作为测试软件开发工具，利用该图形化编程语言完成了测试系统软件部分的设计，实现了测试功能。

It includes: Voice morpher to change singer voice in two dimensions, voice pitch and voice timbre, to be either man, woman, young, old, or characterized; Tempo morpher change tempo to faster or slower; Beat tracking with various preset beats, bongos and drum loops; Cher modulation to create cher effect; 31 realtime single effects which can be combined up to 4 layers; and other audio optimizing tools: advanced tune, beat tracking quality controller, frequency morpher, equalizer.

它包括：语音morpher改变歌手的声音在两个方面，语调和语音音色，无论是男人，女人，年轻的，年老，或特徵；节奏morpher变化速度更快或更慢；禁毒跟踪各种预设的节拍，邦戈鼓鼓循环；雪儿调制创造谢尔的影响； 31实时单效应，可组合多达4层；和其他音频优化工具：先进的调，击败质量跟踪控制，频率morpher，均衡器。

It includes: Voice morpher to change singer voice in two dimensions, voice pitch and voice timbre, to be either man, woman, young, old, or characterized; Tempo morpher change tempo to faster or slower; Beat tracking with various preset beats, bongos and drum loops; Cher modulation to create cher effect; 31 realtime single effects which can be combined up to 4 layers; and other audio optimizing tools: advanced tune, beat tracking quality controller, frequency morpher, equalizer.

它包括：语音morpher改变歌手的声音在两个方面，语音音调和音色的声音，不是男人，妇女，青年，老人，或特点；节奏morpher变化的节奏更快或更慢；巡逻跟踪与各预设节拍， bongos和鼓声循环；谢尔调制创造谢尔效应； 31实时单一的影响，可以结合多达4层；和其他音频优化工具：先进的调重弹，击败跟踪质量控制器，频率morpher ，均衡。

The method includes following steps:(1) initial frequency selection;(2) based on modulation mode adopted, the sending end carries out symbol mapping, changes signal spectrum based on label information of sub channel, and sends signal in time domain;(3) based on label information of sub channel, the receiving end carries out equalization for received signal, demodulates signal and accomplishes judgment;(4) carrying out channel estimation or prediction, the receiving end obtains updated information of signal state, and determines whether label information of sub channel is needed to update based on self-adapting judgment rule.

本发明提供了一种移动宽带信道中的自适应选频分块传输方法，该方法包括以下步骤：(1)初始选频；(2)发端根据所采用的调制方式进行符号映射，根据子信道标记信息改变信号频谱，并发送时域信号；(3)收端根据子信道标记信息对接收信号进行均衡，解调信号并完成判决；(4)收端进行信道估计或预测得到更新的信道状态信息，根据自适应判断规则，判断是否需要更新子信道标记信息。

Uses the automated control not only on the galvanization production line to be possible to raise the product manufacturing efficiency and to reduce worker's labor intensity, and has the very good economic efficiency and the social efficiency, galvanizes on the production line to be possible to realize the automated control using PLC, PLC has the reliability to be high, the compatibility is broad, has the correspondence function, the structure modulation characteristic, therefore how to use good PLC to become the galvanization production line automation control key, auxiliary to galvanized the automatic production line driving with PLC by the frequency changer to carry on the automatic control, had the structure to be simple, the programming was convenient, the operation was flexible, the use safe, worked stable, the perform reliably and the antijamming ability strong characteristic, was one kind of very effective automatic controlThe way, is galvanizes the production to realize, the low cost, the high grade automated production development direction highly effective.

在电镀生产线上采用自动化控制不但可以提高产品生产效率和减轻工人的劳动强度，而且有着非常好的经济效益和社会效益，电镀生产线上运用PLC则可以实现自动化控制，PLC具有可靠性高，适应性广，具有通信功能，结构模块化的特点，因此如何使用好PLC成了电镀生产线自动化控制的关键，用PLC辅以变频器对电镀自动生产线行车进行自动控制，具有结构简单、编程方便、操作灵活、使用安全、工作稳定、性能可靠和抗干扰能力强的特点，是一种很有效的自动控制方式，是电镀生产实现高效、低成本、高质量自动化生产的发展方向。

Frequency Shift Keying is a data communication most commonly used as a modulation mode.

移频键控是数据通信中最常用的一种调制方式。

The motion dynamics and echo models of the precessing warhead in single frequency are set up. Based on a quantitative analysis on echo spectrum and micro-Doppler modulation of precessing cone, a precession parameter estimation method by echo correlation and spectrum width is proposed. The experiments on data by simulation and darkroom measurement verify the method.

建立了单频信号下雷达观测弹头的进动模型和回波模型，通过对进动弹头回波频谱与微多普勒调制特性的定量分析，提出了利用回波相关方法和频谱展宽估计进动参数的方法，并利用暗室测量数据对该方法的性能进行了实验验证。

The compressor works with 70% shoulder undulates in 97% time, in order to guarantee a high operating efficiency, the frequency conversion velocity modulation has taken an adjustment way.

压缩机97%的时间在70%负荷以下波动运行，为了确保较高的运行效率，采用变频调速进行控制。

This paper introduces the application of the programmable controller,the direct current velocity modulation system,the frequency inverter and the electronic cam switch in chamfering machine.

介绍可编程控制器、直流调速系统、变频器、电子凸轮开关在倒棱机中的应用。

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％。