频率

But, in the natural and artificial signal, a lot of signal phases don\'tvary linearly with time, for example, we usually use chirp signal in the radar technology,frequency step signal, linear modulation component of the ground echo in the SARtechnology, linear modulation component of the moving target echo, linear modulationcomponent while the airborn radar detecting the moving target, etc.

在自然界和人工信号中，许多信号的相位变化并不是随时间一次方变化，如雷达技术中常用的线性调频信号，频率步进信号，另外，SAR 技术中，地面回波所含有的线性调频分量，ISAR技术中，运动目标的回波所含有的线性调频分量，机载雷达探测运动目标时的线性调频分量，等等；傅里叶变换对此类信号分析所得的结果是信号在不同频率点上的能量分布，即信号在基函数上的投影。

The genotype and allele frequency of ALDH2 in alcoholic cardiomyopathy group and alcohol dependent group were no difference.

嗜酒组和酒精性心肌病组各种基因型频率及等位基因的频率无统计学差异。

The allele frequency of ALDH2*1 between alcoholic cardiomyopathy group and alcohol dependent group was significantly higher than that in controls and the allele frequency of ALDH2*2 between alcoholic cardiomyopathy group and alcohol dependent group was significantly lower than that in controls.

嗜酒组和酒精性心肌病组ALDH2*1等位基因的频率高於对照(P.01)，ALDH2*2等位基因的频率低於对照组(P.01)。

However, genotype and allele frequencies of this site showed no significant difference among different groups.

但该位点的基因型频率和等位基因频率在三组之间均没有统计学差异。

Results There was no significant difference among 3 groups in genotype frequencies and allele frequencies.

结果 各基因型频率和等位基因频率在3组之间均无显著性差异。

There was no statistical difference either in genotype or in allele frequency between patients with AD and control subjects.

基因型频率和等位基因频率在两组之间无统计学差异。

Frequency is the number of complete cycles per unit of time of any periodically varying quantity, such as alternating voltage or current. It is usually expressed as Hertz or CPS.

频率频率是指周期性变化的事物在单位时间内完成的周期数，常用单位是赫兹或周期/秒。

NTSC uses a quadrature amplitude modulation with a suppressed color carrier and works with amotion frequency of approximately 30 Hz. A picture consists of 525 lines.

NTSC的色彩载波使用接近4.9MHz或3.57MHz的频率，它使用颜色载波进行正交调幅，画面运动频率约为30Hz，每幅画面有525线。

This paper analyses the frequency characteristics of the gear meshing and the signals due to amplitude and frequency modulation.

本文分析了齿轮传动的频率特性和它所产生的频率和幅值调制信号。

Frequency Division Multiplexing is a method of sending multiple analog signals simultaneously over one channel by separating the channel into subchannels, or bands.

司多频率司多频率的方式发送了100多个频道的模拟信号的同时，把渠道变成阶。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐