查询词典 difference frequency

The model of the received power is established based on the basic principles of geometry optics and radiometry. This model provides the principle of receiver-transmitter design and performance evaluation. On the basis of the received power model and APD noise model, the response of measurement signal after passed through the frequency difference circuit and the corresponding change of its SNR are studied.

研究了非合作目标测距时，发射视场与接收视场的重叠情况，以及视场重叠区域内光的探测情况，并以此为基础，根据几何光学和光度学的基本理论，建立了非合作目标测距中接收光功率的数学模型，为接收/发射器的结构设计，以及测距性能的预测提供了理论依据。

Gabor-ring is often used in texture feature extraction, but it is based on the assumption that texture is narrowband signal and can not applied to most actual textured images that have more than one center frequency in power spectrum. To overcome the limitation of existing method, an improved method is proposed. According to this method, Gabor filters are constructed in accordance with the spectrum feature vector of texture, and a relaxation parameter is used to determine the effect of difference filters so as to integrate the frequencies and phases into the process of extraction.

Gabor环（即在频率域成环形分布的Gabor滤波器组）常被用于提取图像纹理特征，但它是以"纹理是窄带信号"为基础的，实际的纹理图像并不能很好地满足"窄带信号"的假设，用一个中心频率来描述一种纹理对能量集中在多个频率点的纹理图像往往不能取得理想的效果，而根据频谱特征值向量构造Gabor环的改进方法，通过松弛因子的加入改变不同滤波器的作用强度，综合考虑了多频率多相位对纹理特征提取的影响。

Because the portal frame is also used in the rig for bogie fatigue strength testing, in which the imposed load is harmonic, the modal analysis is necessary. The fundamental vibration mode shapes and corresponding frequencies are calculated to validating that the natural frequencies of the structure have enough difference comparing to the load frequency, so sympathetic vibration can be avoided.

由于龙门架还要在疲劳试验台中用来进行转向架的疲劳试验，因此对龙门架进行了模态分析，计算龙门架结构的固有频率和振型，确保龙门架的固有频率远离转向架疲劳试验的加载频率，避免在试验中发生共振。

Gas insulated switchgear ; partial discharge ; ultra high frequency method ; finite-difference time-domain ; high voltage insulation technology

气体绝缘组合电器；局部放电；超高频法；时域有限差分法；高电压绝缘技术

A new approach for pattern recognition of ultra-high frequency signals of transformer partial discharge based on multi-scale analysis of wavelet packet and grid dimensionality is proposed, in which the multi-scale transform of wavelet packet is used to extract wavelet coefficients of UHF PD signals and by means of improving difference box-counting method the grid dimensionality of multi-scale wavelet coefficients is calculated and the multi-scale grid dimensionality is taken as the characteristic quantity that is used in the recognition of UHF PD signals.

提出了一种基于小波包多尺度分析和网格维数的变压器局部放电超高频信号模式识别的新方法，采用小波包多尺度变换提取局部放电超高频信号在多尺度上的小波系数，通过改进差盒计数法计算多尺度小波系数的网格维数，并将多尺度网格维数作为特征量用于局部放电超高频信号的识别。

The correlation theory is proposed to calculate phase difference and designed in frequency tracking. A promoted method for the initial measurement of CMF's signal processing is based on the Chirp Z Transform application. The result of simulation has proved that the techniques above are feasible.

应用DFT方法处理科氏流量计的信号是DSP算法的基础，本文除了详细介绍其实现过程，还提出了利用相关函数计算相位差和解决频率跟踪算法中的关键技术以及利用线性调频Z变换实现频率初始化测量的新技术。

Objective to discover the difference of nutritional anemia occurring frequency as well as to emphasize the importance of the reasonable feeding and health education by investigating the diet habits, acceptant levels of hygiene knowledge ,areas and economic factors of the han people and minority people .

目的 通过调查汉族、少数民族在饮食上的习惯、卫生知识接受程度、地域及经济因素的差别，发现营养性贫血发生程度存在差异，强调合理喂养及促进健康教育的重要性。

In the patient group, when comparing patients subject to active infection of any virus with those under no active infection, no difference of statistic significance between them is found in terms of age, course,frequency, admitted temperature, differential leukocyte count (neutrophilic granulocyte,achroacyte and monocytes),applying glucocorticoids or not, and EDSS point value.

病例组中任一病毒近期活动性感染者和无活动性感染者相比，其年龄、病程、发作次数、入院体温、血白细胞分类计数（中性粒细胞、淋巴细胞和单核细胞）、糖皮质激素应用与否及EDSS分值间的差异均无统计学意义。

The difference of their frequency in children and adolesce...

结果DQA1*0301在APSⅢ型、T1DM、AITD中的频率(分别为73.3%、62.1%、57.5%)均明显高于对照组(29.6%)(P均。05)。

There was no significant difference in the allelic frequency

EH组与对照组 SNP位点基因型分布和等位基因频率比较差异

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。