有用信号

提出一种基于快速傅立叶变换（FFT）的算法来计算噪声环境中的有用信号相位，可用于无线通信中双传声器应用系统中的自适应定向。

This paper proposes a Fast Fourier transform ( FFT ) based algorithm to compute the desired signal phase in noisy environments for implementing adaptive directionality of dual microphone application systems such as wireless communications .

根据剩余均方误差随着有用信号功率增加而增加的思想，在S.Ikeda算法基础上提出改进的LMS算法，当输入信噪比越大，步长值应越小，这样可以更好地降低回响。

According to the reason that the excess mean-squared error increases linearly with desired signal power , the modified LMS algorithm is proposed on the basis of S.Ikeda algorithm .

射频干扰会严重影响GPS接收机的工作，导致接收机无法跟踪锁定有用信号，从而无法精确导航定位。而自适应天线是一种有效的抗干扰措施。

Radio-frequency interference will cause severe degradation of GPS receiver , and adaptive antenna is an effective anti-jamming measure for GPS receiver .

针对淹没在1／f分形噪声中的有用信号恢复问题，提出了一种基于小波变换与Kalman滤波的多尺度滤波算法。

A multiscale Kalman filter based on wavelet is proposed for signal restoration embedded in 1 / f fractal noise .

工频干扰是各类基于PC应用系统中最常见的一种干扰信号，对有用信号的检测起着极大的妨碍作用。

The interference by50-Hz noise arising from the power supply cables is common in PC-based application system , often considerably affecting the detection of useful signals .

实验结果表明，设计的CCD视频信号处理电路能够达到去除噪声、提取有用信号的目的。

Experiments show that the design of video signal process circuit can meet the request of getting rid of noise and extract the useful signal .

假设干扰信号和有用信号从不同方向入射到阵列天线上，这里选取PI算法加权对干扰信号产生零陷。

Suppose interference signal and useful signal inject on the array antenna in different directions , the PI algorithm is selected to weaken the interference signal .

然后在小波域内，利用Kalman滤波实现了噪声和有用信号的分离，估计出了各子带中的有用信号。

Some nonstationary properties of fractal signals are attenuated in each subband by wavelet multiresolution decomposition , so that the Kalman filter bank can be applied to estimate the multiscale input signals .

经验模式分解（Empiricalmodedecomposition，EMD）是一种新的信号处理技术，它是基于数据本身的，且能在空间域中将信号进行分解，从而可以区分噪声和有用信号。

Empirical Mode Decomposition ( EMD ) is a relatively new signal processing technique . It starts from the data itself to decompose the signals in spatial domain , so it can discriminate the signals from the noise .

接着本论文给出一种适用于CDMA系统的改进的非线性并行干扰抵消方案。它能够降低来自同信道其他用户对有用信号干扰的不良影响。

Then the paper introduces an improved nonlinear interference cancellation scheme for CDMA that significantly reduces the degrading effect on the desired user of interference from the other users that share the channel .

SVD用于信号的降噪，要重构相空间、进行SVD分解和逆变换，以达到提取有用信号的目的。

SVD is used to reduce signal noise , reconstruction phase space , singular value decomposition and inverse transform , in order to extract useful signal .

由于正交投影算法不利用GNSS信号的方向信息，在抑制干扰的同时，也会削弱有用信号。

Because of orthogonal projection algorithm does not use the DOA information of the GNSS signal , while the interference is suppressed , the useful signal also will be suppressed .

另外，考虑到CIC在通带频率内对有用信号的衰减比较大，设计了补偿滤波器进行补偿处理，并且实现了降采样2倍。

Moreover , after considering the large amplitude attenuation effect of CIC filter on useful signals in the passband frequency , a compensation filter was designed , and 2 times down-sampling was realized .

与传统方法相比，ICA这种空间滤波器不受信号频谱混迭的限制，消噪的同时能对有用信号的细节成分做到很好的保留，很大程度上弥补了时频域方法的不足。

Compared with the traditional methods of artifacts elimination , ICA , a kind of spatial filter , is not restricted by the case of spectrum overlapping , and it has a good reservation of useful detail signals .

在计算机上进行了单路、多路ANC的模拟试验。试验结果表明：利用多路ANC，可以在对信号和噪声具备极少先验知识的条件下，有效地提取在强噪声背景下的有用信号。

The results of the experiment 's indicate that a multiple channel adaptive canceller can effectively detect useful signal in a strongly noisy environment with only a little prior knowledge about signal and noise .

对于阵列系统，往往采用自适应数字波束形成（ADBF）技术，来抑制强干扰和方向性干扰对有用信号的影响。

For array systems , the technique of adaptive digital beam forming ( ADBF ) is adopted to restrain the strong interference and directional jamming .

该方法不但考虑chirp干扰信号chirp率与有用信号chirp率不同的一般情况，还针对干扰信号chirp率与有用信号chirp率相同的特殊情况提出了针对性解决方案。

This method not only considers general case where the chirp rate of chirp interference signal is different from the useful one , but also provides solution for the special case where the interference and the useful signals share the same chirp rate .

在CDMA系统中有用信号、背景噪声和多址干扰并存，多用户检测能够有效地抑制多址干扰，是保证系统容量和通信质量的关键技术。

In CDMA systems signals conveying desired information are received in the presence of ambient noise and multiple-access interference ( MAI ) . Therefore multiuser detection , which can effectively inhibit MAI , is the key technique to ensure the system capacity and the quality of wireless communication .

首先对噪声污染的量测序列用快速傅氏变换（FFT）方法作频谱分析，确定有用信号的截止频率，然后用哈明时窗函数确定滤波因子，即加权滤波的权序列。

By means of Fast Fourier Transformation ( FFT ) spectrum analyses of the series polluted by noises are carried out and the cutting frequency of effective signal is determined . Filtering factors , power series , are obtained by use of function of Hamming time window .

其主要特点是：FIR自适应滤波系数是用输入信号的四阶以上累积量进行更新的；FIR自适应滤波器是收敛于与有用信号类型匹配的滤波器。

The central characteristic of the approach shows that coefficients of the FIR adaptive filter are updated using a recursive algorithm based on a sum of cumulant of orders greater than four of input signal and that the FIR adaptive filter converges to a type of signal-matched filters .

本文就被幅值较高、频带很宽的不规则噪声信号所淹没的微弱有用信号的提取从理论上予以论证，并提出一个采用80C196KC单片机实现的方案。

The implication give evidence for picking up weak signal to be flooded by noise and set forth plan with the help of80C196KC .

其次，课题针对PCMA系统的特点建立了基带信号的传输模型，并从本地信号与有用信号的弱相关性入手，提出了基于相关函数拟合的PCMA系统参数估计算法。

Second , this paper built the base band transmission model of PCMA system , and a new parameter estimation algorithm was proposed on the basis of correlation function fitting .

方法根据剩余均方误差随着有用信号功率的增加而增加的思想，在S.Ikeda算法的基础上，采用改进的算法。

Method Since the excess mean squared error increases with desired signal power , a modified algorithm was proposed on the basis of S.Ikeda algorithm .

研究了加性白噪声环境下有用信号时频表示的估计问题，理论分析和仿真实验表明：有噪信号的STFT和小波变换都可以无偏地估计原信号的相应时频表示；

The theoretic analyses and the simulations show that it is the STFT and the wavelet transform , but the WVD and the pseudo WVD , of the noisy signal are non-biased estimators to the corresponding TFR of the clean signal .

结果对叠加有系统自抖动干扰的信号进行自适应处理，可提高信噪比（约40dB），提取出有用信号。

RESULTS The technology of adaptive processing improved the signal to noise ratio ( SNR ) up to 40 dB of mixed signal with self dithering interference of the system and helped to extract the useful signals .

仿真实验证明，在有用信号和干扰的不同频谱重叠系数下，BA-FRESH滤波器均能够提高输出信噪比，在一定程度上提高扩频系统干扰容限，有利于进一步的信号处理。

The simulation is showing that , under the different percentage of spectral overlap , BA-FRESH can improve the output SNR , elevate the jamming margin , to some degree , and facilitate further signal processing .

多余带宽内的信号对于有用信号来讲就是一种干扰。

The redundant signals actually are interferences for the desirable bands .

这与输入信号中的有用信号和参考信号有关，两者包含的频率成份不能相等；

The component frequencies of the two must not be equal .

混沌噪声中有用信号参数估计的一种新算法

A Novel Algorithm for Signal Parameter Estimation in Chaotic Noise

如何从复杂的谱图中提取有用信号，便是个值得探讨的问题。

How to extract useful information from the complicated spectra is an attractive problem .