基于ARM与DSP的声频数据采集系统设计

结合1个基于ARM与DSP双核架构的声频数据采集系统的开发,介绍了ARM和DSP之间基于HPI通信的接口设计以及A/D、D/A接口设计,说明了接口工作原理及相关配置.提出了一种声频数据采集方案,利用ARM实现控制与人机交互,用DSP做信号处理,给出了数据采集的系统框图和软件流程图.该方案可充分利用DSP的McASP接口实现高精度A/D、D/A转换,利用HPI主机并行接口实现ARM与DSP之间的快速数据传输,从而实现海量声频数据流的高效、实时传输.     

基于USB总线的线阵CCD数据采集系统

文中介绍线阵CCD的USB总线数据采集系统的设计和实现。该系统利用CPLD设计线阵CCD的A/D和二值化数据采集电路,利用专用USB接口芯片CY7C68013设计数据采集计算机接口电路,实现了对线阵CCD输出信号的数据采集和快速处理。该数据采集系统可广泛应用于线阵CCD检测领域。     

I^2C彩电构成特点与检修调试（二）

I^2C总线接口及地址电路大都是模拟电路，而I^2C总线上所传输的数字都是数字信号，为了便于通信，在各被控电路中增加一个I^2C总线接口电路，这就是通常讲的具有I^2C总线控制条件的电路。总线接口由地址发生器、总线解码器、控制开关、锁存器及D／A转换器构成。     

AVR单片机与串行A/D的SPI接口设计

为了解决信号采集系统的同步串行通讯问题,在理解AVR单片机SPI接口的通讯原理和方法的基础上,分析了AVR单片机SPI接口的工作过程,设计了AVR单片机和串行A/D转换器的同步串行通讯接口,并用程序描述了SPI接口通讯的过程,实现了AVR单片机通过SPI接口与串行A/D转换器之间的数据通讯.最后,用实验和数据分析验证了设计方案的可行性.     

一种脉冲噪声下的鲁棒性自适应回波抵消方法

实际通信线路中脉冲性噪声常使得基于高斯噪声模型的经典自适应回波抵消方法的效果变差。针对该问题,提出了一种基于α稳定分布模型的鲁棒性自适应回波抵消方法（RAEC）。该方法采用p稳定分布建模脉冲噪声,在最小平均p范数准则下,利用自适应时间延迟估计器来抵消回波,不仅可以有效地抵消通信线路中含有高斯噪声的回波,而且对含有脉冲噪声的回波也有良好的抵消效果。理论分析和计算机仿真实验表明,RAEC是一种对脉冲噪声具有鲁棒性的自适应回波抵消方法。     

基于FPGA的有源配电网实时仿真器I/O接口设计

分布式电源、电动汽车及需求侧响应资源的广泛接入使有源配电网动态特性变得更加复杂。对基于实时仿真的有源配电网硬件在环仿真提出了新的需求和挑战。基于FPGA(field programmable gate array)的有源配电网实时仿真器具有仿真步长小、仿真精度高、I/O接口丰富、易于扩展、成本低等优点。面向基于FPGA的有源配电网实时仿真器的多种通信需求,以FPGA自身硬件结构为基础,提出了基于FPGA的有源配电网实时仿真I/O接口的设计框架,并设计了用于接收外部设备模拟信号、具有数字滤波功能的高精度通用A/D接口,用于仿真结果输出的通用D/A接口以及用于实现多FPGA全双工通信的高速光模块接口。同时,针对含光伏发电的有源配电网实现了3μs步长的实时仿真测试,其光照强度信号由光照采集器通过A/D接口输入到仿真器中,仿真结果经由D/A接口输出到示波器显示,通过与PSCAD/EMTDC软件仿真结果的对比,充分验证了I/O接口设计的有效性和正确性。     

无线智能家居通信系统抗干扰编解码器的实现

无线智能家居通信系统数据传输过程中,不可避免地会受到室内障碍物、窜内同频率通信设备等干扰因素的影响,造成数据通信可靠性下降.根据无线智能家居通信系统及MCU接口特点,设计了一套基于16 bit MCU接口的(15,11)循环汉明码编解码硬件实现方案,对有效降低误码率、提高系统通信效率具有积极意义.     

用7109A／D实现智能仪表的自动量程转换

由7109A/D芯片构成单片机A/D接口电路,该电路通过改变A/D转换器的基准电压与积分电阻的取值实现自动量程转换功能。     

基于PCI总线的新型脑电信号采集卡的设计与实现

本文介绍了一种基于PCI总线和DSF处理器的新型脑电信号采集卡的设计与实现。利用ADSP2106x卓越的片上处理能力和接口通信能力,设计了DSF与A／D转换器间的链路口接口,以及与PCI接口芯片间的外总线接口,实现了多端口并行数据传输,保证了脑电信号采集处理的实时性、高效性。最后给出了具体的性能参数及与国外同类型产品的比较。     

基于CAN总线的楼宇自控系统设计

提出了一种采用CAN总线的楼宇自控系统的实现方案,完成了主控模块、A/D采样模块、通信模块的硬件和软件设计。依据CAN协议技术规范,制定了信号采集部分的应用层协议。系统采用29bit标识符的扩展帧,定义了具有4部分功能的标识符ID,规定了数据格式,提高了系统的可靠性和数据的传输速率。     

An efficient method for combining adaptive echo and noise canceller in hands‐free systems

Acoustic interferences severely degrade the quality and the intelligibility of the desired speech signal, thus posing a severe problem for many speech applications. Several acoustic echo cancellation (AEC) techniques have been proposed with a view to solving this problem. There are, however, few reports of AEC methods working under real noisy conditions. In this paper, we investigate the maximum positive synergies of the combination of acoustic echo canceller with a new adaptive beamformer. The proposed system achieves both the AEC and noise reduction of speech in an actual environment with real noise sources. Since the AEC is located behind the fixed beamformer of the new adaptive beamformer only one AEC is required for an arbitrary number of array elements, and the AEC does not feel any repercussions from the new adaptive beamformer. The proposed system was implemented in a real environment using National Instruments NI‐PXI‐1042Q controller system and data acquisition card PXI‐4472. Experimental results show that the proposed system has successfully improved the performance of hands‐free systems. Copyright © 2008 John Wiley & Sons, Ltd.     

多参考输入自适应噪声抵消器的算法与实现

针对单参考办入自适应噪声抵消器在多噪声源情况下除噪效果不理想的问题,根据多参考输入自适应噪声抵消器模型,推导了多参考输入最小均方算法,并给出其改进算法。以语音信号为例,给出了多参考输出自适应语音消噪算法及多参考输入自适应语音噪声抵消器的实现方案,并进行了计算机仿真,给出了仿真结果。     

A hybrid noise canceller with a real‐time adaptive Wiener filter and a geometric‐based voice–activity detector for an automotive application

In real‐time environments a speech recognition system in a car has to receive the driver's voice only while suppressing the background noise. This paper presents a hybrid real‐time adaptive filter that operates within a geometrical zone defined around the head of the desired speaker. Any sound outside of this zone is considered to be noise and is suppressed. As this defined geometrical zone is small, it is assumed that only driver's speech is incoming from this zone. The technique uses three microphones to define a geometric‐based voice–activity detector (VAD) to cancel the unwanted speech coming from outside of the zone. However, when unwanted speech and desired speech are incoming at the same time, the VAD fails to identify the unwanted speech or desired speech. In such a situation an adaptive Wiener filter is switched on for noise reduction. In the case of sole unwanted speech incoming from outside of a desired zone, this speech is muted at the output of the hybrid noise canceller. In the case of desired and unwanted speeches incoming together, the SNR is improved by as much as 20 dB. Copyright © 2009 John Wiley & Sons, Ltd.     

A study on adaptive noise canceller using linear phase filter

In this paper, we propose a new adaptive noise canceller using a linear phase filter. The linear model in which an arbitrary signal is defined by the output signal of a linear system at the white signal input is used. The noise is suppressed by the estimated linear system and the signal‐to‐noise ratio is improved. At this point, to minimize the distortion of the signal due to the nonlinearity of the phase shift, the linear phase filter has been newly introduced. The transfer function of the linear system is an arbitrary minimum phase rational transfer function that has poles and zeros. It has the feature of not being specified for all pole models. The adaptive algorithm is a gradient‐based algorithm with few computational complexities. The features of the proposed adaptive noise canceller are that the inverse filter of the adaptive filter is stable, the convergence of the algorithm is guaranteed, the distortion of the signal is minimal, and there is no restriction on the transfer function of the linear system. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(1): 50–55, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21116     

The Effect of Hard Limiters on Signal Detection in Harmonic Noise Using Adaptive Noise Cancellation

Adaptive digital f ilters have been shown to be useful in reducing the power of harmonic noise in distribution line communication systems. Many DLC systems currently in use employ hard limiters to reduce this type of noise prior to detection of the signal. This research shows that the adaptive noise cancellation filter can be used effectively in tandem with hard limiters. The optimal, limit of the limiter is determined in the cases of the presence and absence of the adaptive noise canceller.     

去除电磁辐射测量信号中同频背景噪声的研究

现实环境中由于存在大量的背景噪声,当背景噪声和被测辐射的频率相同时,将导致无法进行精确测量.提出了一种基于递归最小二乘(RLS)自适应对消的精确测量系统,利用接收信号的相关性来将被测信号中同频背景噪声去除掉.分析了实际测量中存在的通道噪声和串扰对测量系统性能的影响.理论分析和仿真结果表明,该技术可以去除同频背景噪声,从...     

同步采样A／D转换器MAX125的原理与应用

文章简要介绍了2×4通道同步采样14位A/D转换器芯片MAX125的功能特点、引脚含义、工作原理及工作时序,给出了MAX125与单片机的接口电路。     

输电线路绕击故障概率分析及雷电预警方法

给出了输电线路雷电绕击概率在线预警方法。通过统计、计算不同地区不同电压等级线路的历史雷电绕击跳闸信息、雷电流强度、侧面落雷距离,应用二维信息扩散理论和条件概率方法建立了输电线路绕击跳闸概率计算模型。在雷电预警过程中,利用气象雷达的回波强度、回波顶高和垂直积累液态水含量数据,建立了基于反向传播神经网络的雷电流幅值预测模型,并通过雷云中心点坐标到线路的水平距离近似计算落雷侧面距离,由此应用输电线路跳闸概率模型,计算线路雷击概率,进行雷电实时预警。算例分析表明了该预警建模方法的有效性。     

Echo canceler algorithm for adaptive Volterra filters in double talk states

In an acoustic echo canceler, it is necessary to consider the nonlinearity of an echo path in order to attenuate an echo signal conventionally, and various methods using adaptive Volterra filters have been proposed. Many of those methods have not resulted in a decisive solution about the double talk states in a nonlinear acoustic echo canceler. In this paper, we propose an echo canceler algorithm for adaptive Volterra filters using the idea of the OECLMS (Orthogonal Expanded Correlation Least Mean Squares) algorithm in consideration of the double talk problem. The convergence speed of the proposed method is improved by using Gram‐Schmidt orthogonalization for the input signal. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 42– 51, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20369