查询词典 difference frequency

The key problems of software radio and direct sequence spread spectrum range used in high range radio fuze are discussed. The effects of doppler frequency and carrier's initial random phase are analyzed. A new direct sequence spread spectrum algorithm based on software radio is proposed, by using differential encoding and quadrature demodulating, the effects of doppler frequency and carrier's initial phase on the output of inference filter are eliminated successfully.

研究了软件无线电和直接扩频测距技术在大炸高无线电引信应用中的关键技术问题，分析了由于多普勒效应引起的载波频偏以及载波随机相位对测距的影响，提出了一种基于软件无线电的直接序列扩频解调算法，通过采用差分编码和正交解调的方法，消除了多普勒频偏和载波随机相位对测距的影响。

Quadric time-frequency distribution can reveal the characteristic of signals by means of the combination of the features of time and frequency domains.

二次型时频分布可以从时域与频域特征相结合的途径揭示信号构成的本质。

During these processes, the system needs to meet the Lamb-Dicke limit, and the Rabi oscillation frequency should be far smaller than the phonon frequency.

在此过程中，系统需满足Lamb-Dicke极限，并要求光场的Rabi振荡频率远远小于离子的振动频率。

By studying the system's dynamic Rabi frequency,it has been found out that trapped population doesn't consist in the magnitude of the Rabi frequency,but in th...

通过对该体系动态Rabi频率的分析，得出：实现布居数囚禁的关键不在于具体Rabi频率的大小，而在于实现Rabi频率的适时跳转。

Is the radian frequency deviation from the center frequency.

是角频率与中心频率的偏离值。

W is the radian frequency deviation from the center frequency.

W 是角频率与中心频率的偏离值。

Radio spectrometer is important method and main instrument of radio astronomy research, through which we can research radio astronomy phenomenon in wide frequency spectrum and continuous time with high frequency resolution and high temporal resolution.

射电频谱仪是通过高的频率分辨率和高的时间分辨率，在广泛的频谱范围内和连续的时间演化上进行射电天文观测的仪器，它是射电天文研究的重要方法和主要工具。

Accelerated scanning of TDMA cellular channels may be obtained by tuning the cellular radiotelephone to a succession of frequency channels within one TDMA time slot and measuring signal strength for each of the succession of frequency channels.

将蜂窝无线电话调谐到一个TDMA时隙中的一系列频率信道上并为该频率信道序列中的每一个信道测量信号强度，以此获得对TDMA蜂窝信道的加速扫描。

By projecting signals with different frequencies into the subspace I, the signal with the supply frequency has the maximum value. Consequently, in the spectrum of the reciprocal of the projecting value, the supply frequency component is cut off and the fault feature component emerges in the spectrum.

把不同频率的信号投影到子空间I，基频信号在该空间的投影将远大于其他的频率分量，因此在投影的倒数谱中，基频分量被抑制，凸显出了故障频率分量。

Often divided into two types:(1) sine wave oscillator, according to the network oscillation frequency of the different loop selected further divided into RC sinusoidal oscillator, LC sinusoidal oscillators, quartz crystal oscillators, voltage-controlled oscillator, voltage-controlled crystal oscillator and other forms;(2) non-sinusoidal oscillation device, also known as relaxation oscillator, is the use of capacitor charging and discharging and active device (transistor, FET, single-junction transistor, etc.) to generate the pulse-off square wave, rectangular wave, triangle wave, sawtooth wave, or these basic waveforms synthetic waveform and its frequency by the LC time constant charge and discharge circuits to decide.

常分两大类型：（1）正弦波振荡器，根据振荡环路中选频网络的不同，又分为RC正弦波振荡器、LC正弦波振荡器、石英晶体振荡器、压控振荡器、压控石英晶体振荡器等多种形式；（2）非正弦波振荡器，又称张弛振荡器，是利用电容充放电及有源器件（晶体管、场效应管、单结晶体管等）的通断来产生脉冲方波、矩形波、三角波、锯齿波或这些基本波形的合成波形，其工作频率由LC充放电电路的时间常数来决定。

For the head-teacher of the class said that I had seriously broken the school rules,which led me to a three-day suspend class.

为什么呢？因为我的班主任说我严重的违反了校规，于是让我停课三天。

Many of them believe that the conversion of thousands of working-class folk in England spared that nation from the mass carnage and the tyranny that came with the revolution in France.

他们之中有许多人相信，在英国数以千计的劳工阶级之悔改信主使英国免於遭受如法国大革命所造成的大屠杀和专制暴政。