频率调制

An expression for acoustic wave amplitude as a function of modulation frequency and relaxation time has been derived.

推导了光声信号振幅与入射光调制频率和样品分子振动－平动弛豫时间的函数关系。

The way the transmitter audio response is measured is to apply a fixed modulating signal level which produces 60% of rated system deviation (3 kHz in our case) at 1000 Hz.

要测量发射音频的频率响应，方法是加上一个固定调制信号电平，这个电平在1000HZ下产生系统设计频偏的60%（这里是3KHZ）。

A false signal in telecommunication links from beats between signal frequency and sampling frequency .

在脉冲编码调制中，信号频率和取样频率之间的差拍所引起的伪信号。

In addition,the modulation frequency has no effect on the dynamical characteristics,only changing the number of the evolution pattern.

另外，调制频率的改变不影响系统的动力学性质，只改变系统演化模式的出现频率。

In the third part of the paper, another novel technology, named as Mould Oscillation-less Electromagnetic Continuous Casting under AMMF was proposed in order to replace the huge mechanical mould oscillation system by AMMF imposing outside the mould in continuous casting.

进行了三种波形高频调幅磁场下的无结晶器振动电磁连铸初步实验研究，实验结果表明：在方波、三角波和正弦波调幅磁场作用下的无结晶器振动电磁连铸过程中，当调制波频率略低于系统固有频率时，弯月面与结晶器壁间断接触距离最大。

Fundamental frequency is either equal to the switching frequency of the inverter(square-wave and PWM inverter)or ist simple fraction(1/3,1/5,and so) such as in Multiple PWM or sine PWM inverters.

基本频率是逆变器在相等的开关频率，或者方波是简单的分数(1 / 3，因此，1 / 5)，如在多个PWM脉宽调制逆变器或正弦量。

Altera Corporation system to the Cyclone FPGA series of digital platform, microprocessor, bus, Digital Frequency Synthesizer, memory and I / O interface hardware concentrated in an FPGA, the use of direct digital frequency synthesis technology and digital modulation waveforms required to achieve the rise, Using FPGA ROM storage of the DDS waveform table, and make full use of on-chip resources, improve the system's accuracy, stability and robustness.

系统以 ALTERA公司的 Cyclone 系列 FPGA 为数字平台，将微处理器、总线、数字频率合成器、存储器和 I/O 接口等硬件设备集中在一片 FPGA 上，利用直接数字频率合成技术、数字调制技术实现所要求波形的产生，用 FPGA 中的 ROM 储存 DDS 所需的波形表，充分利用片上资源，提高了系统的精确度、稳定性和抗干扰性能。

Localization length of the system with twoincommensurable perturbing frequencies is much larger than that of the systemwith one perturbing frequency.

数值分析表明：如果对振幅和相位调制的两个频率是不可约的，那么这个系统的局域长度要比单个频率扰动时大得多。

The simulation results indicate that adjusting pump power properly can control transient effect, and increasing modulation frequency can weaken cross modulation, and decreasing frequency chirp of LD or enhancing the input power of signals can improve intermodulation distortion.

仿真结果表明，调整泵浦功率值可抑制瞬态效应，提高调制频率可使串话减弱，减小激光器的频率啁啾或增大EDFA的输入光功率都可改善IM2。

A carrier wave is the radio frequency wave generated at a transmitting station for the purpose of carrying the modulated frequency wave.

载波 载波是传输站为携带调制频率波而生成的一种无线频率波。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。