查询词典 difference frequency

As a parallel transmission technique with multi-carriers, Orthogonal Frequency Division Multiplexing is very suitable for high data rate transmission because it has the advantages of being robust to frequency selective fading, high spectrum efficiency and simple equalizer.

正交频分复用作为一种多载波并行传输技术，能够有效对抗多径信道的频率选择性衰落，同时具有较高的频谱利用率，接收端的均衡也很简单，非常适合于高速率数据传输。

An algorithm base on Pro-ESPRIT and MR-ESPRIT of simultaneous estimation of frequency and 2D AOA with spatial-temporal sub-Nyquist sampling is proposed. The frequency estimation algorithm is suit for arbitrary geometry of antenna array.

提出了基于时空欠采样条件、Pro-ESPRIT方法和多分辨意义下的宽频段入射信号频率和二维到达角估计方法，并指出，其中的频率估计算法适用于任意几何结构阵列。

This paper applies Fourier series to detach the fundamental waves phase, adopts the curve fitting to the frequency of the maximum spectrum amplitude, utilizes the sine wave parameters of law to the phase angle of this frequency, calculates δvalue and tanδvalue.

本文以傅立叶级数分离基波相位的方法为依据，通过曲线拟合求频谱幅值最大值处的频率，利用正弦波参数法求该频率处的相位角，从而计算出δ值和tanδ值。

Have originally designed of variable frequency sinusoidal wave generator 、 the frequency of measurements, and the interval between cycles of equipment.

本设计以单片机为核心设计了一种可变频率的方波、正弦波的发生器，并可测量频率、周期和时间间隔的仪器。

Utilize mathematical operation of the one-chip computer and control the function, combine the digital circuit of some scale of China, have realized the producing of variable frequency sinusoidal wave and the measurement of frequency , cycle , width of pulse to the signal ,etc.

利用单片机的数学运算和控制功能，结合部分中规模数字电路，实现了一些波形的输出，及对信号的频率、周期、脉冲宽度等的测量，使用单片机使整个系统具有极为灵活的可编程性，能方便地对系统进行功能扩展与改进。

The stealth warplane for the microwave radar usually have complicated structures with the coating of wave absorption. On the base of calculation and modeling of the geometrical structure of the warplane in real size, the HF RCS of the air crafts under two different polarizations in different direction have been calculated with the FDTD. The result shows that the above mentioned stealth warplane have the obvious characterstics of frequency resonance, polarization and the relatively large RCS in HF Band 10-30dBm2, which can be used as the theoretical reference for selection of working frequency for sky wave OTH Radar and it also means that the sky wave OTH radar has good capability of anti-stealth targets quantitatively.

对微波雷达具有隐身作用的飞机，其形体较为复杂且表面涂敷有强吸波材料在对一种具有隐身几何外形结构实际尺寸飞机进行计算建模的基础上，文中采用FDTD技术得到了两种极化状态下该飞机无涂敷时不同方向上的短波雷达截面RCS值其结果显示了这种隐身几何外形飞机在短波波段有明显的频率谐振特性、极化特性和较大的RCS10-30dBm2，可为天波超视距雷达在选择工作频率时提供理论参考，并定量地说明天波超视距雷达具有较优的反隐身目标能力

To implement policies and regulations of national radio management, to draft local laws and regulations of radio management; to be in charge of the assignment and management of radio frequency resources according to the national plans; to examine and endorse allocation of addresses and usage of radios, to assign frequency and call letters, to issue the licenses for radio stations, to be in charge of collecting fees that concern radio management; to organize and direct the construction of wireless monitoring net and the monitoring work for electromagnetic environment, to organize and implement the supervision towards radio in accordance with the law, to maintain the order of electric wave in the sky, to be in charge of administrative enforcement of Law of radio management; to guide and supervise agencies of radio management, to undertake the foreign affairs of radio management.

贯彻执行国家无线电管理的政策、法规，起草无线电管理地方性法规和规章；依据国家规划，负责无线电频率资源的指配与管理；审批无线电台的地址设置和使用，指配频率和呼号，核发电台执照，负责无线电管理有关收费工作；组织指导无线电监测网建设及电磁环境监测工作，依法组织实施无线电管制，维护空中电波秩序，负责无线电管理行政执法；对无线电管理派出机构进行业务指导和监督，承办无线电管理涉外事宜。

The metal magnetic material was adopted to satisfy EMI resistance equipment in GHz frequency, due to its higher saturation magnetic susceptibility than the ferrite material, lamella structure and higher frequency in Snoek limit than that of the ferrite material.

由于金属磁性材料的饱和磁感应强度高过于铁氧体，微波段的磁导率高，有利于实现薄层化， Snoek极限值所到达的频率高过于铁氧体材料，所以可以采用金属磁性材料来满足GHz频段抗干扰器件的要求。

In the last few years, researches the problem of the underwater sail machine's sound have been common, the content of the research is very extensive, including the modeling, method of its solution, frequency curve, the wave's property in spreading, the syntonic frequency and the damp material on such coupling system.

近几年，水下航行器的声振一直是国际上研究的热点，研究的内容非常广泛，其中涉及这类耦合系统的建模、求解方法、频散曲线与传播波性质、外激励下的共振频谱及阻尼材料降噪等。

Use the Frequency Spectrum display to measure the approximate value of the fundamental frequency of the wire on the Sonometer.

使用频谱显示测量振动频率计上金属丝基频的近似值。

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。