数字递推滤波器在抗工频及倍频干扰信号上的应用

对高于香农频率的工频及倍频干扰信号，本文提出了利用程序查找其干扰频率的数字递推滤波方法进行滤波，并将它应用到ＷＹ－２型钢水测温定氧智能仪中，从而有效地解决了抗工频及倍频干扰信号的问题。     

带干扰雷达型目标模拟器校准方法

为解决雷达型目标模拟器中干扰信号参数的校准难题,提出一种基于软件无线电思想的校准方法,通过对目标模拟器输出的回波信号下变频,并进行数字化处理,匹配预设的干扰信号模型,解算出干扰信号参数,实现带干扰雷达型目标模拟器的校准。研建雷达型目标模拟器校准系统,对某型目标模拟器进行校准,并对校准结果进行不确定度评定。校准结果表明:干扰信号参数误差3%以内,拖引速度不确定度1 m/s,拖引加速度不确定度0.2 m/s~2,干扰信号捕获、拖引、保持与关机时间的不确定度为0.01 s,校准结果证明该方法可以应用于带干扰雷达型目标模拟器的校准。     

一种AFS接收机的设计

文中对AFS接收机主要技术指标进行较详细的分析,给出一种AFS接收机的设计方法:采用接收通道、频率控制电路、对数放大电路、干扰分析组件来分析和处理干扰信号,电路简捷,且具有动态大、快速捷变频等特点.该AFS接收机在阵列多波束雷达、机载相控阵雷达中得到广泛应用.     

自适应跟踪数字陷波滤波器的设计与应用

本文采用自适应跟踪数字陷波滤波器自动跟踪被测信号中干扰信号的频率 ,并利用该频率设计相应的数字陷波滤波器去除被测信号中的干扰信号。试验表明 ,该方法具有设计简单、应用方便、实时性强等特点 ,可以有效去除被测信号中频率缓慢变化的干扰信号     

数字式电脑多频涡流检测仪在电厂中的应用

目的 消除电站热交换管板信号干扰，提高检测信噪比。方法 采用4个独立频率的检测通道，混频处理后干扰信号，结果 在理论分析与实验室大量模拟试验基础上开发出国内第一台数字式电脑多频（四频）涡流检测仪，并在电厂中得到应用。结论 现场使用证明该仪器具有操作方便，检测速度快，抗干扰灵敏度高等特点。     

谐波干扰作用下柔性结构振动的增益调度H∞控制

针对柔性结构受到随系统运行工况的变化而改变频率的谐波干扰作用下的振动控制问题，提出了一种新的增益调度H∞控制器设计方案，首先，对谐波干扰信号建模，并将该模型与系统结构模型结合形成广义模型，然后，选取二次性能指标将谐波干扰作用下振动抑制问题转换为标准的H∞控制器设计问题，最后，采用增益调度技术对典型谐波频率所设计H∞控制器的输出进行模糊加权插值，从而获得随谐波干扰频率变化的控制器输出，通过与LQC和一般的H∞控制器进行数值的仿真比较，验证了方法的有效性。     

工频干扰振动信号的建模与分离处理

针对钻井泵振动测试过程中遇到的工频干扰，采用信号的基元分段方法进行测试信号的合理分段处理，结合最优频率匹配法实现分段后干扰信号的建模分析。在此基础上提出振动信号的匹配滤波法，实现干扰信号与钻井泵振动信号的匹配滤波分离。实践表明，最优频率匹配法可以实现各种信号的数学建模，是一种通用性的信号建模处理有效的新方法，而且建立在该方法基础上的匹配滤波法也可以较为完整、合理地分离各种时、频域混叠信号，是一种适应性强的信号滤波处理新方法。     

自适应跟踪数字带阻滤波器的设计及应用

采用自适应跟踪数字带阻滤波器自动跟踪被测信号中干扰信号的频率,并利用该频率设计相应的数字带阻滤波器去除被测信号中的干扰信号.结果表明,该方法具有设计简单、应用方便、实时性强等特点.     

在线自动检测系统干扰信号的排除与抑制

排除和抑制干扰信号和噪声往往是在线、自动检测系统成败的关键。由于通常检测的是非电量，其干扰信号不仅仅包括电磁干扰和热噪声，而且包含非电干扰，若只采用通常电气系统抑制干扰和噪声的手段往往不能完全奏效。本文总结了排除或抑制上述干扰信号的若干途径，供设计、建立或分析在线、自动检测系统时参考。     

论地对空雷达干扰系统在局部战争中的作用及其发展

文章介绍了从地对空干扰机的发展概况,从单一干扰轰炸瞄准雷达,发展成地对空干扰系统和系列,可以干扰空载作战飞机雷达、导弹制导雷达、精密制导雷达、预警机雷达、星载探测雷达等,分析了这些雷达的干扰原理、干扰方法和干扰机的布局。文章对新体制雷达的干扰压制系数进行了分析,导出各类新体制雷达的干扰压制系数表达式,并提供了计算机仿真和实际试验的结果。文章分析了90年代以来两次现代化局部战争,地对空干扰系统若能发挥作用,将使被入侵国家的损失率下降,使入侵者的损失率升高。地对空干扰系统具有攻防兼备的立体干扰系列功能,需要经费较低,很适合于第三世界国家的需求,具有广泛的发展前景。     

采用数字相关法测量相位差

本提出了一种用数字相关法测量相关位的方法,并加以详细讨论了和误差分析。本方法具有精度高,抗干扰能力强,硬件少,适用于低频测量等特点。     

基于数字相关原理的相位差测量新方法

提出了一种基于数字相关原理的相位差测量新方法，该方法直接对两被测信号作互相关运算，并利用相关和正弦函数的一些性质，使部分噪声分量被有效地与有用信号相分离，从而提高了抗随机干扰能力和测量的准确度。理论分析和数字仿真结果表明：该方法具有不必预先知识正弦信号频率、抗随机干扰能力强等特点；其测量准确度和信号的信噪比和数据采集卡的位数有关，可通过调节总采样样本点数减小它们的影响。     

Noise,anti-noise and fluid flow control

This paper celebrates Thomas Young's discovery that wave interference was responsible for much that is known about light and colour. A substantial programme of work has been aimed at controlling the noise of aerodynamic flows. Much of that field can be explained in terms of interference and it is argued in this paper that the theoretical techniques for analysing noise can also be seen to rest on interference effects. Interference can change the character of wave fields to produce, out of well-ordered fields, wave systems quite different from the interfering wave elements. Lighthill's acoustic analogy is described as an example of this effect, an example in which the exact model of turbulence-generated noise is seen to consist of elementary interfering sound waves; waves that are sometimes heard in advance of their sources. The paper goes on to describe an emerging field of technology where sound is suppressed by superimposing on it a destructively interfering secondary sound; one designed and manufactured specifically for interference. That sound is known as anti-sound, or anti-noise when the sound is chaotic enough. Examples are then referred to where the noisy effect to be controlled is actually a disturbance of a linearly unstable system; a disturbance that is destroyed by destructive interference with a deliberately constructed antidote. The practical benefits of this kind of instability control are much greater and can even change the whole character of flows. It is argued that completely unnatural unstable conditions can be held with active controllers generating destructively interfering elements. Examples are given in which gravitational instability of stratified fluids can be prevented. The Kelvin-Helmholtz instability of shear flows can also be avoided by simple controls. Those are speculative examples of what might be possible in future developments of an interference effect, which has made anti-noise a useful technology.     

Time-frequency-based non-stationary interference suppression for noise radar systems

The problem addressed here is non-stationary interference suppression in noise radar systems. Towards this aim, two linear time ?frequency (TF) transforms, short-time Fourier transform and local polynomial Fourier transform are used as a means of signal representation and filtering. The noise radar return signal is a wideband random signal occupying the whole TF plane, whereas the interference signal is well concentrated in the TF plane. This implies that the filtering of the received signal can be performed by using a binary mask to excise only a portion of the TF plane corrupted by the interference. Simulations carried out on the radar return signal corrupted by extremely strong non-stationary interferences confirm the effectiveness of the proposed method.     

Application of Wavelet Packet De-noising in Time-Frequency Analysis of the Local Wave Method

The local wave method is a very good time-frequency method for nonstationary vibration signal analysis. But the interfering noise has a big influence on the accuracy of time-frequency analysis. The wavelet packet de-noising method can eliminate the interference of noise and improve the signal-noise-ratio. This paper uses the local wave method to decompose the de-noising signal and perform a time-frequency analysis. We can get better characteristics. Finally, an example of waveletpacket denoising and a local wave time-frequency spectrum application of diesel engine surface vibration signal is put forward.     

Mutual interference and low probability of interception capabilities of noise radar

Recently, there has been considerable interest in noise radar over a wide spectrum of applications, such as through-wall surveillance, tracking, Doppler estimation, polarimetry, interferometry, ground penetrating or subsurface profiling, detection, synthetic aperture radar (SAR) imaging, inverse SAR imaging, foliage penetration imaging etc. Major advantages of using noise in the transmit signal are its inherent immunity from radio frequency and electromagnetic interference, improved spectrum efficiency, and hostile jamming as well as being very difficult to detect. The basic theory of digital signal processing in noise radar design is treated. The theory supports the use of noise waveforms for radar detection and imaging in such applications as covert military surveillance and reconnaissance. It is shown that by using wideband noise waveforms, one can achieve high resolution and reduced range estimation ambiguity. Mutual interference and low probability of interception capabilities of noise radar are also evaluated. The simulation results show the usefulness of the noise radar technology to improve on conventional radars.     

锁定放大技术用于扫描隧道显微镜

介绍了锁定放大技术应用于扫描隧道显微镜(STM)中调制隧道间隙而获得物质表面原子的局域势垒分布的原理,并给出了高定向石墨的观测结果,与恒电流模式下STM图像相比较,具有分辨率高、针尖的影响小、抗干扰性能强的特点。另外,根据局域势垒分布还可区分不同的原子,给解释STM原子图像提供了一种手段。     

True-Power Measurement in Digital Communication Systems Affected by In-Channel Interference

A new cyclostationarity-based method for power measurement in digital communication systems in the presence of in-channel interference is proposed. The new method takes advantage of the signal-selective properties typical of algorithms based on cyclic spectral analysis. The true-power measure is achieved from the noisy data by estimating the cyclic spectrum of the desired signal at a cycle frequency not shared with noise and interference. The performance of the method is evaluated through several experiments on spread-spectrum and pulse-amplitude-modulated signals and with reference to different types of interfering signals. The method exhibits very good performance even when the desired and interfering signals completely overlap in both temporal and spectral domains.      

变频调速器在张力控制系统中的应用

变频调速器的应用越来越广泛，本文简单介绍了用变频调速器在卷绕式镀膜机中实现两段张力控制的方法，对其中的控制原理及抗干扰方面进行了简单的说明。     

On scheduling models for the frequency interval assignment problem with cumulative interferences

In this article, models and methods for solving a real-life frequency assignment problem based on scheduling theory are investigated. A realistic frequency assignment problem involving cumulative interference constraints in which the aim is to maximize the number of assigned users is considered. If interferences are assumed to be binary, a multiple carrier frequency assignment problem can be treated as a disjunctive scheduling problem since a user requesting a number of contiguous frequencies can be considered as a non-preemptive task with a processing time, and two interfering users can be modelled through a disjunctive constraint on the corresponding tasks. A binary interference version of the problem is constructed and a disjunctive scheduling model is derived. Based on the binary representation, two models are proposed. The first one relies on an interference matrix and the second one considers maximal cliques. A third, cumulative, model that yields a new class of scheduling problems is also proposed. Computational experiments show that the case-study frequency assignment problem can be solved efficiently with disjunctive scheduling techniques.