基于DSP的语音录放和数字回声的实现

数字信号处理是现代数字语音通信的核心技术之一,DSP技术的应用为实现语音信号的采集、处理和播放奠定了基础.设计基于DSP的语音信号处理系统,运用TMS320VC5416处理器和AIC23语音芯片构建出硬件平台.分析DSP处理器和Codec芯片性能特点,配置软件控制接口,实现数字音频数据通信传输.采用C语言和汇编语言混合方式编写系统主程序和模块子程序,调试实验语音处理系统的信号采集、数字回声和播放,实现语音处理系统设计功能.     

基于LabVIEW的数字信号处理虚拟实验室构建

本文首先简要介绍了当前数字信号处理教学的现状,并针对目前实验室的具体情况,分析了研究虚拟实验室的必要性及意义。并在此基础上使用LabVIEW构建了数字信号处理虚拟实验室。该系统界面友好,维护简单等优点。此外,用户可以根据需要对典型的数字信号处理实验参数进行设置。实验证明该系统具有很好的教学实验效果。     

Digital image processing-an object-oriented approach

This paper presents a class library dedicated to digital image processing which provides resources for essential digital image processing operations. Besides its practical value, the class library is used to teach both object-oriented software engineering methodology and digital image processing. The resulting module can be accessed from independent specialized applications through its public interface while its implementation details are perfectly encapsulated. First of all it is used as the inner part of an integrated environment designed for students and researchers in the field of digital image processing. This software component was built aiming for both portability and extendibility. It contains attributes and methods that allow for a wide range of digital image processing algorithms: point and geometric operations; filter, edge detection, segmentation and texture operations; and fast Fourier transforms, discrete cosine transforms, and wavelet and Gabor transformations. All these can be used for image enhancement, restoration, compression, analysis, and synthesis     

基于并行NCO的宽带数字下变频器

为了解决当前数字下变频器对硬件处理速度要求过高的问题,设计了一种基于并行NCO的宽带数字下变频器,将并行处理与多相滤波相结合,可以大大降低对处理速度的要求,有效解决数字信号处理的瓶颈问题。仿真结果表明,该宽带数字下变频器成功实现了对数字中频信号的下变频、滤波抽取等功能,输出结果正确,可实现宽带接收处理。     

A digital signal processing laboratory for undergraduates

An undergraduate level laboratory on digital signal processing (DSP) is described. The equipment used and samples of student experiments are described in detail. The lab is based on the TMS320 digital signal processor and is equipped with spectral analysis and audio signal processing capabilities. The primary purpose of the lab is to supplement a course on digital filter design and implementation. However, it can also be used for senior design projects involving DSP applications     

Meeting the analog world challenge. Nyquist-rate analog-to-digitalconverter architectures

To bring digital processing and its benefits to bear on real-world applications, the analog signal of interest must be translated into a format a digital computer can utilize. This is the function of the analog-to-digital converter (ADC). After processing by a digital computer or digital signal processor (DSP), the resulting digital stream of information must be returned to its analog form by a digital-to-analog converter (DAC). The methods by which a digital code is generated within the ADC are diverse. We introduce three popular Nyquist-rate ADC architectures used today: the counter ramp ADC, the successive approximation ADC and the flash ADC     

Digital signal processing with applications: a new and successfulapproach to undergraduate DSP education

The new approach to undergraduate digital signal processing education at Purdue is based on a simple idea: emphasize applications. Students are assumed to have a significant exposure to sampling and discrete-time signals, systems, and transforms at the junior level. In the senior course, the traditional digital signal processing topics of digital filter design, the discrete Fourier transform (DFT), radix-2 fast Fourier transforms (FFTs), and quantization are covered in the first five weeks of the semester. Coverage of these topics is augmented by treatment in the laboratory component of the course using diverse software tools and by Matlab-based homework assignments. The remainder of the course is devoted to treating the topics of speech processing and image processing in substantial depth and involves a design project. The course has been very successful in terms of increasing enrolment and outstanding student evaluations     

数字信号处理对电子测量与仪器的影响研究

数字信号处理(digital signal processing,DSP)和电子测量与仪器(electronic measurement and instrument,EMI)的关系密不可分,已是众人皆知的常识。以数字信号处理对电子测量仪器的影响为切入点,逐一探赜DSP与EMI的关系。首先说明测量的重要性,接着列举了DSP改善和提高了主要电子测量仪器的性能;最后论述了DSP突破了传统测量理论的限制,可使数字存储示波器的潜力发挥到极致。     

Benefits of digital hearing aids

The author examines the physiological and psychological characteristics of the impaired ear and attempts to develop an understanding that can be used as the basis for designing a hearing aid. In addition, the limitations of today's hearing aids are examined. Secondly, new technology, such as digital signal processing, are examined as to its potential in hearing aid applications. Is digital processing practical and what are the potential benefits? Lastly, future directions of hearing aid research and development are discussed     

基于DM642高速异纤图像检测处理系统的硬件设计

待加工原棉中往往混有难以分辨的异性纤维,能否有效地的去除这些杂质关系到棉纺产品的质量和企业的生存。本文设计了一种以FPGA为数据采集逻辑控制单元,以DSP为高端图像处理单元的数字图像处理。介绍了该系统的硬件组成、工作原理。从视频编码单元、图像处理单元和视频输出单元对整个系统的构成和设计进行了描述,分析了系统设计时的各个关键技术环节。     

Pulse-domain digital image processing for vision chips employing low-voltage operation in deep-submicrometer technologies

A new architecture for pixel-level parallel image processing in the pulse domain for CMOS vision chips has been developed. Image processing such as edge enhancement, edge detection, and blurring are realized based on suppression and promotion of digital pulses; the pixel value is represented by the frequency of digital pulses by use of a pulse-frequency modulation (PFM) photosensor or that with an in-pixel 1-bit analog-to-digital converter. The proposed architecture is suitable for low-voltage operation in deep-submicrometer technologies because the image processing is implemented by 1-bit fully digital circuits with a small number of logic gates. The principles of the image processing are addressed. We have fabricated a 16 /spl times/ 16-pixel prototype vision chip. The relationship between illumination and the output pulse frequency is characterized. Step responses of the prototype vision chip for fundamental image processing operations show good agreement with those expected by correlation-based spatial filtering. A simple image binarization method specific to our architecture is also presented. The histograms of the intervals of the output pulses after image processing show multiple peaks, which indicates that averaging of the intervals is required for longer periods to achieve higher image-processing quality. To improve the linearity of pulse frequency dependence on illumination, usage of random clocks is discussed.     

多路数字语音记录仪

本文介绍一种多路数字语音记录仪的结构及其关键技术。该仪器基于PC机结构并融合了高速DSP技术和语音数字处理的研究成果     

The role of lossless systems in modern digital signal processing: atutorial

A self-contained discussion of discrete-time lossless systems and their properties and relevance in digital signal processing is presented. The basic concept of losslessness is introduced, and several algebraic properties of lossless systems are studied. An understanding of these properties is crucial in order to exploit the rich usefulness of lossless systems in digital signal processing. Since lossless systems typically have many input and output terminals, a brief review of multiinput multioutput systems is included. The most general form of a rational lossless transfer matrix is presented along with synthesis procedures for the FIR (finite impulse response) case. Some applications of lossless systems in signal processing are presented     

基于MATLAB的高效自动化通信实验平台

伴随着通信技术的不断演进,数字通信实验平台在操作效率和处理速度上面临着挑战.为此,采用MATLAB作为中央控制平台,为实验仪器编写了各自的通信接口程序,实现了对于信号发射机、信号接收机和数字电源的软件控制,并利用MATLAB强大的信号处理能力,开发出一套软硬件结合的自动化数字通信实验平台.该平台利用软件指令调控可编程仪器,进行数据采集和过程监控,并完整实现了调制、发射、接收、解调等通信过程.在日常实验和教学中,该实验平台可有效提高通信实验系统的自动化程度和运行效率,其软件系统具有很高的开放性,使用者可以根据不同的实验方案进一步开发所需的软件功能.     

数字量输入式合并单元的白噪声处理

为了提高数字化采样的可靠性及精确度,白噪声问题一直是工业界和学术界的研究热点。首先,结合智能变电站的应用实例,给出了电子式互感器的输出波形,并对白噪声分量进行频谱分析。进而,考虑滤波效果、算法稳定性、延时时间等因素,设计了相应的数字滤波器,并给出了滤波参数及处理结果。最后,结合非周期分量衰减时间常数、最大峰值瞬时误差等指标,分析和评估了滤波算法对暂态性能的影响。分析结果表明,数字滤波算法可以使白噪声削弱一半以上,且不会影响暂态性能。     

电力线通信系统中的信道训练和信道估计方案

在对电力线信道进行估计的过程中采用信号处理方法，将通信数据与部分已知的训练数据相结合，通过在频域和时域进行信号变换和算法处理实现了电力线通信中的信道训练与数据通信的兼容性和实时性，节省了信道的带宽并提高了信道估计的准确性和稳定性。最后通过实验证明了所提出的信号处理算法的有效性。     

一种基于TMS320F2812的数字滤波器的快速设计方法

本文指出了数字滤波器是现代数字信号处理的重要基础,阐述了数字滤波器的基本原理。介绍了利用TI公司提供的数字滤波函数库filter tool进行数字滤波器设计的方法,并给出了在MATLAB软件中实现的滤波器设计效果波形和实验波形。实验表明,此方法方便实用,可以很好地在TMS320F2812上进行数字滤波。     

Development of distributed relaying processor with digitalfiltering of fast sampled data

In order to cope with advanced relaying techniques, a multimicroprocessor-based digital relay was developed. The main features are distributed processing among five processors, 32-b floating-point operations, digital filtering of fast sampled data, and a personal computer based testing tool. Performance tests of this digital relay showed the following characteristics: (1) the error of any relaying element (distance, overcurrent and undervoltage) was less than 1%; (2) operating time was less than 20 ms when the processing interval was 1.67 ms; and (3) a single relaying processor had a computational capacity of six-phase (ground, short×4 steps×3 phases) distance relays based on differential equations, accompanying elements, and a self-diagnosis function in every processing interval     

基于AD2S1200的旋变接口电路设计及信号处理

应用旋转变压器/数字转换器AD2S1200,将旋转变压器输出的模拟信号转化为数字信号,以便于DSP进行处理。介绍了旋转变压器的基本原理,设计了AD2S1200与旋转变压器及TMS320F2808型DSP的接口电路,并提出了一种容错性较强的位置信号数字处理方法。实验证明,该设计方法精度高,可靠性好,抗干扰能力强,完全能够满足高速电机控制系统的要求。     

电机微机测试的数字滤波方法

用微机测试三相异步电动机的性能参数时,由于某些不正常因素的干扰,使采样数据中含有“坏值”。本文给出了数字滤波的五种方法,供编制数字滤波处理程序时使用。