建筑施工有源振动噪声主动抑制系统设计

针对绿色建筑施工过程中的有源噪声问题,设计一种新的建筑施工有源振动噪声主动抑制系统,抑制建筑施工产生的高分贝噪声,避免影响当地居民生活、损害施工场地管理人员的听力。该系统通过传声器MIC1和MIC2采集建筑施工有源振动噪声信号后,采用LMS自适应滤波算法,去除噪声信号中干扰因子并通过数控放大器放大,将放大后的噪声信号传输至信号处理器中,先采用基于梯度下降的次级通道在线建模有源噪声控制方案,准确计算次级通道传递函数,再设定抑制噪声指令,叠加噪声控制信号与噪声信号,实现有源振动抑噪。经验证,某建筑施工场地降噪前噪声最大分贝高达79 dB,使用该系统后,噪声分贝数值降低到27～32 dB之间。实验不仅验证了该系统的有效性,还验证了系统具有较高的降噪量与降噪速度优势。     

A robust DL MU-MIMO algorithm and UE specific SINR compensation mechanism in LTE-A

针对多用户特征模式传输（MET）算法这种典型的多用户多入多出（MIMO）算法,现实系统中实现时有两个重要限制：其一要求发射端的和功率约束;其二假定噪声、邻区干扰功率项在基站侧已知且将其建模为加性高斯白噪声（AWGN）。在现实系统中,一方面最好遵循每天线发射最大功率的限制,另一方面需要考虑对噪声、邻区干扰功率项的建模,以期望在基站侧更好模拟用户设备（UE）端最终真实感受到的噪声与干扰功率。基于此,提出了一种鲁棒的针对LTE-A的下行多用户MIMO技术,即自适应的切换波束赋形权值归一化算法。同时,基于该归一化的波束赋形权值,提出一种UE级的信干噪比（SINR）补偿机制。使用该补偿的UE级的SINRs,一方面可基于如容量最大等准则,挑选获得给定调度资源上的最优多用户配对集;另一方面,针对该最终配对的多用户集,使用每UE的补偿SINRs做链路自适应,即MCS选择,从而期望获得系统整体和吞吐量的提升。最后,给定仿真参数,链路级仿真结果验证了所设计算法的有效性。     

基于虚拟传声的双通道有源噪声控制

以有源耳罩为对象研究了基于虚拟传声的双通道有源噪声控制问题。双通道即在传统单通道有源噪声控制系统的基础上增加一个次级通路。由于两个通道之间存在相互耦合,因此控制难度加大。使用基于虚拟传声器技术的自适应多通道FxLMS算法,应用一阶前向差分预测算法通过自适应变权值预测控制目标区域内的残余误差信号。仿真结果表明,通过该方法可以使目标静音区的噪声信号明显衰减。     

新的自适应盲噪声抑制在语音处理中的应用

传统的自适应滤波去噪的系统中需要一个参考信号,实际中一般事先并不知道噪声的特性,而且噪声也是时变的。因此提出一种新的基于盲噪声抑制方法,可降噪并跟踪噪声特性的变化,随时调节滤波器的系数,比传统的自适应噪声控制具有优势。     

一种新的自适应语音增强系统

针对自适应噪声对消(ANC)语音增强系统的性能高度依赖于参考信号的质量，任何原始语音信号泄漏到参考信号中，都会导致原始语音信号失真和噪声抵消性能恶化这一问题，本文提出一种对泄漏不敏感的附加随机噪声(ARN)自适应噪声对消语音增强系统。它通过在参考信号中加入一个低功率的宽带随机训练信号，然后用该训练信号作参考信号对噪声传输函数(NTF)进行自适应建模，并在使用自适应预测滤波器(APF)消除NTF自适应建模的语音信号干扰的同时，用补偿滤波器(CPF)来修正由APF引起的参考信号失真。计算机仿真表明，这种ARNANC语音增强系统在泄漏情况下能将原始语音信号从带噪语音信号中有效分离出来。     

有源抗噪声头戴耳机

有源噪声控制为抗噪声头戴耳机提供了一种新的方法。文章读者讨论了有源抗噪声头戴耳机的理论机制，说明它在降噪的同时可以保留有用的通讯信号，并通过对于一种反馈控制系统的分析展示了这种耳机的实验设计与效果。     

空间自适应有源噪声控制技术

应用有源噪声控制理论,在比较反馈控制结构和前控制结构后,提出采用模型参考自适应中的ＭＲＡＳ趋稳定性设计方法,构造一种反馈结构自适应降噪的实施方案。实验表明,消声效果明显。     

自适应有源噪声控制器的设计与实现

论述了自适应有源噪声控制器的设计原理及实现方法，给出了通用型自适应有源噪声控制器的硬件结构和软件流程，作为实例，设计了一台通用型自适应有源噪声控制器，并提供了该控制器用于有源噪声控制的实验结果。     

封闭空间内的多模型自适应有源前馈噪声控制

误差通道建模是实现自适应有源噪声控制算法的重要环节.由于次级通路建模误差对整个系统稳定性有重要影响,利用Modified FXLMS算法结合多模型自适应控制与封闭空间误差通道特性,提出一种针对封闭空间自适应有源控制的多模型算法,完成了该算法的性能分析和计算机仿真.     

基于DSP的自适应有源噪声控制系统

文章介绍了基于TITMS32 0F2 4 0DSP的自适应有源噪声控制系统 ,给出了系统的硬件结构及其工作原理 ,详细说明了有源噪声控制的自适应算法 ,并给出了程序流程图及实验结果。通过实验证明 ,该系统有较好的降噪效果。     

Multiantenna adaptive modulation with beamforming based on bandwidth-constrained feedback

Adaptive modulation has the potential to increase system throughput considerably by adapting transmission parameters to the time-varying channel characteristics. Crucial to adaptive systems is the requirement of a feedback channel, that is often capable of carrying only a limited number of bits. Under such a bandwidth-constrained feedback link, we aim to optimize a multiantenna system based on transmit beamforming and adaptive modulation, where the transmit power, the signal constellation, the beamforming direction, and the feedback strategy, are designed jointly. Our proposed nested iterative approach leads to an approximate, yet practical, solution. Simulation results demonstrate considerable improvement in transmission rate, as the number of feedback bits increases.     

基于DSP的自适应噪声消除系统

自适应噪声消除技术在信号处于噪声很强的环境中时,可以非常有效地将噪声去除掉。而DSP是一种高速、高性能的专业数字信号处理器,用DSP实现自适应噪声消除,其具有很好的实时性和处理精度。在此完成了基于DSP的自适应噪声消除系统,有效地消除了信号中的噪声。     

On the performance of adaptive modulation in cellular systems

Adaptive modulation techniques have the potential to substantially increase the spectrum efficiency and to provide different levels of service to users, both of which are considered important for third-generation cellular systems. In this work, we propose a general framework to quantify the potential gains of such techniques. Specifically, we study the throughput performance gain that may be achieved by combining adaptive modulation and power control. Our results show that: (1) using adaptive modulation even without any power control provides a significant throughput advantage over using signal-to-interference-plus-noise ratio (SINR) balancing power control and (2) combining adaptive modulation and a suitable power control scheme leads to a significantly higher throughput as compared to no power control or using SINR-balancing power control. The first observation is especially important from an implementation point of view. Adjusting the modulation level without changing the transmission power requires far fewer measurements and feedback as compared to the SINR-balancing power control or the optimal power control. Hence, it is significantly easier to implement. Although presented in the context of adaptive modulation, the results also apply to other variable rate transmission techniques, e.g., rate adaptive coding schemes, coded modulation schemes, etc. This work provides valuable insight into the performance of variable rate transmission techniques in multi-user environments     

Optimal feedback control of direct-current motors

A methodology for real-time speed control of a thyristor-driven DC motor in the presence of measurement noise and load torque disturbance is developed. An optimal state feedback controller using the Kalman-filter state estimation technique is derived. This is followed by an adaptive control algorithm to compensate for the effects of noise and disturbance. These two algorithms working together are capable of providing a very high-speed regulation and dynamic response over a wide range of operating conditions. Simulated responses using an i80386-based PC with a mathematics coprocessor are presented to highlight the effectiveness of the control strategy     

Joint optimization and threshold structure dynamic programming with enhanced priority scheme for adaptive VANET MAC

Nodes in vehicular ad-hoc network (VANET) are highly mobile, traversing in unpredictable and varying environment. Therefore, contention window size and transmission power should adapt according to the high mobility transmission environment. In this paper, we propose an adaptive VANET medium access control (MAC) layer with joint optimization for VANET (MACVS) which aims at minimizing average delay and maximizing packet success rate. An adaptive joint optimization with proposed threshold structure dynamic programming, with closed loop feedback control system, is designed to optimize contention window size and transmission power. Adaptive optimization is done based on road traffic conditions and transmission reliable distance range (depicted by interference and noise), by monitoring the continuous change and threshold of received signal strength to interference and noise ratio. Mathematical expressions have been developed for the MACVS optimization framework, and the produced analytical results show good agreement with the simulation results. Simulations with different arrival rates and urban map of city center show that the proposed MACVS with low complexity joint optimization effectively reduces end-to-end delay while achieving high packet success rate under various network traffic condition.     

基于MATLAB的自适应噪声抵消器的设计与实现

阐述了自适应噪声抵消（ANC）技术的基本原理,基于自适应滤波器的原理,设计了自适应噪声抵消器;在对自适应滤波器相关理论研究的基础上,重点研究了自适应噪声抵消器的核心——LMS自适应滤波算法。在MATLAB中的Simulink下,建立了自适应噪声抵消器的模型,并通过设置不同的参数进行仿真,结果表明系统能够有效地从噪声中恢复出原始信号。最后对系统进行了性能分析,给出了自适应噪声抵消系统在实际应用中选取参考信号的要求。     

自适应抵消技术在随钻测井信号处理中的应用

随钻测井中,井场上的机电干扰和工业干扰对信号有明显的影响,为此提出了利用自适应噪声干扰抵消技术滤除噪声,提高信噪比。自适应噪声抵消器是自适应滤波的一种重要应用,它利用对消的方法抑制干扰,而把被污染的信号提取出来,因此可以将一路以有用信号为主同时含有部分噪声干扰和另一路主要是噪声信号的两路信号分别作为自适应噪声干扰抵消器的原始输入和参考输入进行自适应滤波。实验结果表明,自适应噪声抵消器能够有效滤除井场噪声,提高信号的信噪比。     

Scheduling strategy for networked control system based on variable sampling period and deadband feedback

A scheduling strategy of variable sampling period combined with deadband feedback for networked control system is proposed. Variable sampling period algorithm can allocate a reasonable sampling period to each controlled loop according to the network utilization and packet transmission time. Deadband feedback algorithm can alleviate network congestion by appropriately adjusting the packets in the network when the networked control system cannot be scheduled. According to the actual overload and utilization of the network, the designed scheduling strategy dynamically adjusts the sampling period and priority, and improves the performance of the system combined with deadband feedback. Based on the TrueTime platform, the proposed scheduling strategy is verified on a three controlled loops networked control system with interference nodes and limited network resources. The simulation results demonstrate that the designed scheduling strategy can overcome the uncertainty of the upper bound of network resources, improve output control performance, reduce integral absolute error value of the controlled loop, and shorten the packet transmission time. The overall control performance of the system is improved. The designed scheduling strategy is effective.     

下行信道质量受控反馈算法与调度算法的研究

该文先介绍了在第三代移动通信技术体制cdma2000 1xEV-DO/DV中的下行信道质量反馈机制;然后提出了一种新的反馈控制算法,并结合一种综合考虑吞吐量和公平度的调度算法(正比公平调度算法)进行了分析与仿真。通过与未采用该策略的调度算法结果相比较,显示了新的算法在保持公平度的条件下能够提高系统吞吐量,同时减少了移动台的功耗,这种新的算法应用灵活,其策略对其它需要对共享资源调度的领域也有意义。     

一种适用于宽带无线IP网络的分组调度算法

自适应调制技术在许多新型的无线分组网络如WCDMA HSDPA、HiperLAN/2中得到广泛采用.本文在充分考虑自适应调制系统链路带宽随时隙呈不平均分布特点的基础上,提出一种全新的调度算法,自适应区分补偿公平队列(ADCFQ).该算法采用了基于工作量的分析方法,设计了不同功能的多个子队列,可以为系统所有待发流提供基本的QoS保证,为各个流公平共享剩余带宽,并能够通过合理的补偿机制克服无线环境中突发错误影响.分析和仿真结果表明,这一算法可以满足目标要求.此外,仿真中,针对自适应链路的特点,本文还提出了一种基于多状态Markov链的信道建模方法.