噪

On the contrary, in this frequence point the S/N ratio maybe lower.

由于地震数据不同频段有不同的信噪比，常规的去噪方法对信噪比低于一定程度的频率成分就起不到压制噪声的作用，相反，在这样的频率点可能还会降低信噪比。

In this case, the received carrier is modulated by unknown Doppler frequency and frequency rate. The estimation techniques as maximum likelihood estimator and extended Kalman filter are described and compared in our dissertation by tracking a common simulated highdynamic trajectory.

文中详细推导了任意信噪比情况下，时延和多普勒频率估计的方差下限表达式：在信噪比高于门限信噪比的情况下，具体推导了估计方差的Cramer-Rao限；在信噪比低于门限信噪比时，估计的方差下限还与失锁概率有关。

To estimate the high signal to noise ratio in every recorded trace using quantitative method and erase the recorded traces with low signal to noise ratio so as to form a standard trace with high signal to noise ratio.

在形成标准道时，利用定量估计信噪比的方法，对每个记录道分段进行信噪比估计，剔除信噪比低的记录段从而形成高信噪比的标准道。

The db4 wavelet was applied in signal de-noising and the translation invariant wavelet was used to eliminate the Gibbs phenomenon .

对电力系统接地短路电流信号的去噪进行了研究，针对小波去噪等信号处理方法中存在的 Gibbs现象，提出并研究了采用db4小波进行信号去噪，采用平移不变小波变换，并以新型阈值代替传统阈值，进一步改善了去噪效果。

Wheel/rail noise of the high-speed slab track on concrete bridge and that of the urban elevated supporting block track are predicted respectively. Noise of the slab track, compared with that of the ballasted track, is more severe. The noise of the slab track is about 6.2dBA higher than that of the ballasted track for the receiver nearby the rail, and about 3.5dBA higher than that of ballast track for the receiver

对降低高速铁路桥上板式无碴轨道及城市轨道交通桥上支承块式无碴轨道轮轨噪声的技术措施进行了研究，包括：(1)分别就板式轨道和支承块式轨道结构参数的低噪声设计原则进行了研究；(2)对几种典型的新型轨道用吸声材料的降噪效果进行了分析，结果表明降噪效果显著；(3)就声屏障高度、位置、形状以及声屏障内侧敷设吸声材料对降噪效果的影响进行了分析，结果表明：声屏障越高、越接近轨道，降噪效果越好；声屏障内侧敷设吸声材料，可降低钢轨近旁噪声2.0～3.0dBA，可降低近地面噪声约1.5～2.0dBA

The results show that both methods of wavelet and EMD are effective, while the method based on EMD, which filters signals and eliminates the noise selectively according to spectrum character of decomposition signal, is the optimal method that can sufficiently keep the non-stationary character inhered in signal and provide well auto-a-daptability, flexibility and affectivity and feasibility in filtering and denoising of rock blasting and impact fragmentation signals.

结果表明：采用小波与EMD 2种滤波、消噪的方法都能获得较好的效果，而基于EMD滤波、消噪法是依据信号分解结果的频谱特性进行选择性的滤波和消噪，更能充分保留信号本身所固有的非平稳特征，具有自适应强和灵活、有效的特点，是一种更好的爆破振动信号滤波、消噪法。

We also study on the coding performance of these wavelet. At last, we investigate the wavelet threshold denosing for image, and present a improved Bayes denosing for image. We also combine the wavelet image coding with image denosing based on wavelet threshold, the noising image is compressed, the noise is de-noised at the same time.

最后，在对小波阈值的图像降噪原理进行分析的基础上，提出了一种改进的贝叶斯图像降噪方法，并将小波图像压缩和图像降噪结合在一起，来实现对噪声图像进行压缩的同时对它进行降噪。

Firstly, the effects of vibration signal de-noising among Fourier transform, wavelet decomposition and wavelet packet decomposition were compared. Secondly, the singular value decomposition was applied to de noise vibration signals. Finally, a new de noising method integrated with wavelet packet and singular value was put forward.

首先对傅里叶滤波降噪、小波降噪和小波包降噪的效果进行了对比，然后将奇异值分解技术用于信号降噪，最后提出了一种将小波包和奇异值分解相结合的降噪方法。

In comparison with the current version, in which the signal-to-noise ratio accuracy of the noisy signal produced is heavily influenced by 'clean' signal itself, the proposed approach has removed this unfavorable impact by choosing another factor to rescale the signal.

在目前广泛使用的加噪信号方法中，产生的信噪比精度受无噪信号的影响很大，与之相比，新方法通过选择新的因子对信号进行归一化，剔除了无噪信号对产生的加噪信号的信噪比影响。

Audio denoising is the pre-step in the audio processing,and wavelet domain denoising has been a main research area.In order to give people a summary knowledge of wavelet domain audio denoising,based on many literatures,this paper attempts to make a survey of wavelet domain audio denoising.First,it introduces wavelet transformation and the characteristics,and gives the optimal selecting and dealing criterion of wavelet domain denoising,the basis wavelet selection.Second,describes five classical methods of audio denoising,for example,threshold,multi-wavelet,wavelet packet,modulus maximum and scale correlation,then introduces their development.Third,introduces a new algorithm based on modulus maximum and scale trading theory.At the end,the future trend of wavelet domain audio denoising is pointed out.

音频降噪是音频处理前期的必要步骤，小波域降噪是其中一个重要的研究方向，为了使人们对小波域音频降噪有概括了解，在对小波域音频降噪相关文献进行分析和理解的前提下，首先介绍了小波变换及其特性，同时阐述了小波降噪的最优选取和处理准则，及对音频进行小波变换时小波基的选取原则；然后评述了用于音频降噪的阈值，多小波、小波包、模极大值和尺度相关法等5类方法及各自的发展；接着介绍在前人基础上，提出新的基于模极大值和尺度理论的降噪算法；最后探讨了小波域音频降噪的发展方向。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。