查询词典 noise

Due to the fact that the intercarrier spacing in OFDM is relatively small, OFDM transceivers are somewhat more sensitive to phase noise compared to single carrier transceivers. Thus this problem must be carefully considered in designing an OFDMbased system since an accurate prediction of the tolerable phase noise can allow designer to relax system specifications. According to spectrum theorem, two components of phase noise were analyzed: common phase error and intercarrier interference. On the basis of the analysis, the performance of OFDM was given for the case where phase noise has been added to the signal, and an optimal design criterion for OFDM parameters was proposed that allows to improve the phase noise error correcting capabilities in OFDM receiver.

由于采用子载波间相互正交的结构，OFDM系统对于由本地振荡器不稳定性所导致的相位噪声影响非常敏感，针对公共相位误差CPE和载波间干扰ICI两种影响表现形式不同的干扰项，从功率谱密度函数这一独特角度分析了相位噪声对OFDM系统性能的影响，提出了旨在提高接收机抵抗相位噪声能力的OFDM系统关键参数优化与设计准则，可在对所设计OFDM系统性能加以提高的同时，有效降低对接收机前端模拟振荡器件和相位噪声抑制单元的性能指标要求，从而降低接收机硬件实现成本。

Methods : The noise intensity and spect ral analysis were monitored with HS6288 noise inspector.Cumulative noise exposure was calculated according to noise intensity and working age. Testof Audio acuity was carried out for 931 noise exposure workers,who are with non - otopathy.

用HS6288 系列噪声分析仪监测作业场所噪声强度，并进行频谱分析，计算累积噪声暴露量；对某纺织厂接触噪声作业的无耳疾患的931人进行听力检测；用EpiData 建立数据库，SAS 软件8.0 统计包进行统计分析。

This method can make sure the structure radiant sound status in total noise and the detail phonate part quickly and correctly.(3) Study on the control mechanism of structure noise radiated from rotary machines, we build a common model of rotary machine structure noise analysis relied on the general characters of rotary machines. Based on this model, we analyzed various influence factors to structure radiant noise using the union of revolution and numerical calculation method. We found that the joint stiffness between the rotor and the frame is the most sensitive parameter of structure radiant noise by calculating and analyzing.

根据本文对于旋转机械结构噪声控制技术的研究结果和惯性振动筛工作的特殊要求，对有关参数的选择进行了讨论，并通过试验为降低惯性振动筛噪声找到了两个新的方法：即，在轴间相对运动要求不高的情况下，可以在激振器与筛体之间安装一组减振器，通过适当选取减振器参数，既可以使机体在工作频率附近获得稳定振幅，保证振动筛正常工作，又可以使机体的高频响应减小，降噪效果显著；反之，如果轴间相对运动精度要求(来源：1aABC论文网www.abclunwen.com)较高，可以采用空心滚动体轴承，在保证滚动体强度的条件下也可以获得较好的降噪效果。

At first, setting up the arith relation between the signal input and the signal output of the generalized multi-carrier system of the Discrete Fourier Test spread-spectrum; then setting equilibria parameters of the frequency field equilibria subcarrier of the generalized multi-carrier system of the DFT spread-spectrum according to channel frequency response, channel noise variance and equilibria method; then calculating average power of useful signal, interferential average power between signals as well as noise variance of the generalized multi-carrier system receiving terminal of the DFT spread-spectrum according to the arith relation as well as the frequency field equilibria parameter, and recomputing available signal information noise ratio, so as to calculate the available signal information noise ratio of the generalized multi-carrier transmission system accurately, the method for estimating the available signal information noise ratio can be used for link self-adapting transmission solution of the generalized multi-carrier system based on Discrete Fourier Test spread-spectrum and radio material management.

一种DFT扩频的广义多载波系统的SINR估计方法，其通过首先建立所述离散傅立叶变换扩频的广义多载波传输系统的信号输入输出之间的数学关系，然后根据信道频率响应、信道噪声方差和均衡方法，设定所述DFT扩频的广义多载波传输系统的频域均衡子载波的均衡系数，再根据所述数学关系及所述频域均衡系数分别计算所述DFT扩频的广义多载波传输系统接收端有用信号的平均功率、信号间干扰的平均功率以及噪声方差，再计算有效信干噪比，如此以实现对广义多载波传输系统的有效信干噪比的准确计算，该有效信干噪比估计方法可用于基于离散傅立叶变换扩频的广义多载波传输系统的链路自适应传输方案和无线资源管理方面。

This paper,through measuring and analyzing the noise sources in the hot-dip galvanization workshop of a steel tube plant,indicated that the operation of inner blowing tube is the major environmental source of noise pollution,studied the mechanism of air current noise for blow pipe,put forward comprehensive administer steps with sealing cap,pressure reduction,noise elimination and noise insulation.

噪声治理工程初步实施结果表明，内吹管噪声瞬时峰值降低了10~15dB，厂界噪声瞬时峰值降低了20dB以上，收到了良好的工程效果。

In order to establish the complete dynamic simulation model for the heat recovery steam generator and develop an advanced drum level controller, the methods of probability and time series were used to analyze the field data on drum level sloshing noise. The mean value of the drum level was removed and the field data was de-trended to get the true sloshing noise. Meantime, the AR model was set up for the drum level sloshing noise, and simulation results show that the model realizes matching simulation of the drum level noise signals in the power spectrum. The model can also match the drum level noise successfully in the time domain.

为建立完整的余热锅炉系统动态仿真模型，并基于此模型开发先进水位控制器，采用概率统计和时间序列分析的方法，对现场采集的汽包水位晃荡噪声信号进行了分析，去除汽包水位均值和趋势以获得真实的汽包水位晃荡噪声，建立了相应的汽包水位晃荡噪声仿真AR模型；模型的仿真结果表明：AR模型从功率谱上对信号数据进行了匹配模拟，且使用该模型作为噪声模块在时域上对汽包水位晃荡噪声信号进行了成功匹配。

Removing different kinds of impulsive noise in image is systematically researched, and proposes three image removing noise filter based on fuzzy information processing technique, i e., fuzzy entropy-based filter for removing noise in multilevel image, histogram-based filter for removing salt and pepper noise in image, and histogram- based adaptive filter for removing image impulsive noise.

该章对图像中不同类型加性脉冲噪声的去噪问题进行了系统地研究和分析，提出了三种基于模糊信息处理的图像平滑去噪滤波器，分别为基于模糊熵的多值图像去噪滤波器、基于直方图的图像椒盐噪声滤波器、基于直方图和区域信息的自适应图像脉冲噪声滤波器。

With the obtained model of the power spectrum, we have theoretically analyzed the contribution of all the amplitude noise, timing jitter and pulse width jitter to the total noise power spectrum. The simulated results show that while the product of pulse width and angular frequency is larger than 1, the pulse width jitter will contribute an amount of noise to the total noise power.

利用得到的模型，理论分析了激光输出光脉冲各个噪声项对总噪声功率谱的贡献情况，并数值模拟了输出脉冲功率谱，结果表明在脉冲宽度角频率积大于1的情况下，脉冲宽度抖动对总噪声功率谱有很大的贡献。

The purposes of this study were to explore noise distribution, its timing, and sources of peak noise in the neonatal intensive care unit of a University Hospital in Southern Taiwan. Two surveys on noise distribution and peak noise of the warmer bed were conducted.

本研究之目的为探讨南部某一所大学附设医院中新生儿加护病房噪音之分布情形及其与时间的关系，以及发生突发性高度噪音之频率和相关来源。

Most of the frequency（1455.99 ± 187.09 Hz to 3534.13 ± 301.53 Hz）of songs in Chinese bulbul are overlapped with environment noise（under 3000Hz）. In order to study the impact of urban noise on the song performances of Chinese bulbul, this study was carried out at Taichung urban areas focusing on the difference of dialects between different environment noise habitats（Shu Yi Area, Chung Hsing University, Taichung Metropolitan Park） from March to November 2007. In addition to the 3 study sites, I sampled another 6 sites （Fengle Park, Taichung Park, Botanical Garden, Art Boulevard, Ren De Village, Tong Lin Village）to find out the differences of songs frequency resulted from different environment noise habitats.

为了探讨都市噪音对白头翁鸣唱的影响，本研究於2007年3至11月以微地理尺度，探讨台中市都会地区三个不同程度噪音干扰的栖地环境(树义地区、中兴大学、台中市都会公园)之间白头翁歌曲的方言差异；另加入六小样区（台中市丰乐公园、台中市台中公园、台中市国立自然科学博物馆植物园区、台中市国立美术馆绿园道、台中县乌日乡仁德村、台中县雾峰乡桐林村），探讨在不同的噪音值干扰下，有关白头翁歌曲音频的表现。

Article 144 The Government of the Hong Kong Special Administrative Region shall maintain the policy previously practised in Hong Kong in respect of subventions for non-governmental organizations in fields such as education, medicine and health, culture, art, recreation, sports, social welfare and social

第一百四十四条香港特别行政区政府保持原在香港实行的对教育、医疗卫生、文化、艺术、康乐、体育、社会福利、社会工作等方面的民间团体机构的资助政策。原在香港各资助机构任职的人员均可根据原有制度继续受聘。

Small wonder, then, that the Chinese spend more in the shop than any other group of foreign visitors do .

这样的小惊喜，使中国顾客比任何国家的人消费得更多。