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     

The SIVA Demonstration Gallery for signal, image, and video processing education

The techniques of digital signal processing (DSP) and digital image processing (DIP) have found a myriad of applications in diverse fields of scientific, commercial, and technical endeavor. DSP and DIP education needs to cater to a wide spectrum of people from different educational backgrounds. This paper describes tools and techniques that facilitate a gentle introduction to fascinating concepts in signal and image processing. Novel LabVIEW- and MATLAB-based demonstrations are presented, which, when supplemented with Web-based class lectures, help to illustrate the power and beauty of signal and image-processing algorithms. Equipped with informative visualizations and a user-friendly interface, these modules are currently being used effectively in a classroom environment for teaching DSP and DIP at the University of Texas at Austin (UT-Austin). Most demonstrations use audio and image signals to give students a flavor of real-world applications of signal and image processing. This paper is also intended to provide a library of more than 50 visualization modules that accentuate the intuitive aspects of DSP algorithms as a free didactic tool to the broad signal and image-processing community.     

An in-circuit emulator for TMS320C25

An in-circuit emulator (ICE) is a piece of indispensable equipment in developing a microprocessor-based system. Digital signal processor (DSP) chips like the TMS320 family are VLSI processors with superior 16-bit microcomputer internal architecture, and are designed to support a wide range of computation-intensive and high-speed applications. Development tools, such as full-speed emulators and software simulators for DSP chips, are either too expensive or too complicated to be used in laboratory classes for teaching purposes. This paper describes the design and implementation of a low-cost in-circuit emulator for the TMS320C25 that has all the necessary facilities for debugging hardware and software. A window-based user interface has been incorporated to allow maximum user friendliness. The emulator is now widely used by engineering students in the Chinese University of Hong Kong for experimental work and project development employing TMS320C25 DSP chips in digital filtering, speech analysis, image compression, and other applications     

基于DSP的双路频率-电压转换器的实现

在安卓手机控制外设的应用中,如果有效运用音频输出的频率信息,则可以拓展手机的控制方式。为此,按应用场合,需要测量输出音频信号的频率,并将其转换为模拟电压信号。介绍测周法测量数字信号频率的原理,给出测量误差与时基频率的关系,并详细论述系统软硬件平台的设计思路及实现方法,使用TMS320F28335型DSP处理器测量双路数字信号的频率,并以数模转换器DAC7724相应线性输出双路模拟电压信号,最后给出该系统的转换误差、转换时间与输出更新率。     

核脉冲波形甄别

文中分析核脉冲波形堆积和传统的全硬件核脉冲信号处理电路,提出基于DSP和高速A/D的波形甄别系统方案,可有效地实现去脉冲堆积和脉冲幅度测量,减小系统的死时间,也简化模拟电路设计。在此基础上,可设计新型单道和多道幅度分析仪等核测量仪器。     

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.     

电子式电流互感器低压侧电路的多功能化实现

电子式电流互感器(ECT)低压侧电路是与继电保护设备接口的关键环节.文中对有源ECT的低压侧电路进行设计,实现了模拟量输出和基于数字信号处理器(DSP)的数字量输出,并利用DSP强大的数据处理能力,实现了ECT就地频率测量和谐波分析等功能;研究并实现了ECT快速校验算法,嵌入DSP的校验模块使得ECT能够完成就地校验;最后对设计的各功能模块进行了实测.低压侧电路的模块化、多功能实现将极大地拓展其应用范围.     

基于DSP、CPLD和单片机的高速数据采集装置设计

为满足数据采集过程中对频率和分辨率等技术指标方面上的更高要求,设计了一种高速数据采集装置。该装置利用2片A/D芯片将输入的电压、电流模拟信号转换为数字信号,送往复杂可编程逻辑器件(CPLD),并利用2组RAM进行实时存储数据。CPLD产生A/D芯片的控制时序,以及2组RAM的读写控制时序;数字信号处理芯片(DSP)输出控制A/D转换的原始信号,并通过CPLD读写RAM中的采样数据,然后传送给单片机,最后利用单片机的USB接口将采集数据传送给PC机。分析了高速DSP的引导装载过程,并利用单片机实现了DSP程序的引导装载功能。通过在模拟雷击实验和继电器实验中的应用,表明该装置能够提供高速的数据采集和数据传送功能,性能可靠。     

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     

A senior project course in digital signal processing with theTMS320

A senior project course on applications in digital signal processing (DSP) with the TMS320 digital signal processor is described. All experiments and projects are performed using Texas Instruments' TMS320 digital signal processor. The laboratory emphasis in the senior project course reinforces the concepts of DSP covered in the lecture course. Applications in DSP are in areas such as communications, controls, speech, graphics, etc. The DSP projects presented and demonstrated by the students in the spring of 1987 are discussed. These projects can provide a guide to individuals who may incorporate a hands-on approach to DSP in courses such as senior project, senior lab, or DSP lab using the versatile TMS 320 digital signal processor     

磁浮列车测速定位装置

随着数字信号处理理论和可编程数字信号处理器（DSP）芯片的发展,DSP的应用越来越广泛.本文介绍了用于磁浮列车测速的DSP数据采集和处理部件,该部件包括模拟信号采样单元、DSP处理单元、数据存储单元、逻辑控制单元.并介绍了该部件与其他部分的通信接口方法.实践证明该部件完全符合要求,有一定的实用价值.陈德林,男,上海同济大学控制科学与工程系硕士研究生.     

基于并行数据处理结构的电能质量在线监测

提出了基于现场可编程门阵列器件FPGA与数字信号处理器DSP并行结构的在线电能质量监测与分析。由FPGA同步产生系统控制时序,并充分利用FPGA与DSP各自在数字信号处理领域中的特点,在FP GA内设计了16位浮点FFT运算模块用于谐波分析,应用DSP实现电压波动与闪变等电能质量指标数据的计算,采用FPGA与DSP并行数据处理的方式,达到采样与数据处理的同步进行的目的,从而完成对多路信号的无缝采样与分析。     

基于DSP的多通道高精度数据采集系统

本文研究一种多通道高精度数据采集系统,解决现代电子测量仪器高精度和高速度之间的矛盾.4路模拟信号分别经过低通滤波和程控放大后,由4路模/数转换器同时转换成数字信号,并由高速DSP芯片进行数字滤波、时域/频域变换等数字信号处理.主机接口采用高速PCI接口,大大提高了主CPU数据处理速度.本设计已经成功应用于国内最新开发的多款高性能高精度电子测量仪器中,数据采集的精度和速度指标完全满足设计要求.     

A −40-dB EVM 20-MHz subsampling multistandard receiver architecture with dynamic carrier detection,bandwidth estimation,and EVM optimization

In this work, a reconfigurable multistandard subsampling receiver with dynamic carrier frequency detection and system-level EVM optimizations is proposed. Ideal software defined radio (SDR) receivers promise complete flexibility at the expense of high-performance analog-to-digital converters (ADCs) that are challenging to implement in current technologies for low-power applications. This scenario leads to the research of digital intensive sampling receivers with discrete-time signal processing (DTSP) implemented in analog domain. This approach makes it feasible to move channel selection filtering and dynamic gain adaptability from analog to digital domain. The proposed receiver employs subsampling down-conversion along with subband filters to dynamically detect the carrier frequency of the incoming signal, estimate its bandwidth, and identify if the signal is present in one of the target standard bands. This carrier detection provides a unique capability to reconfigure the receiver dynamically. Additionally, in this work, system-level EVM optimization is proposed considering frequency synthesizer phase noise, IQ mismatch, sampling frequency selection and block-level gain, noise, and nonlinearity. The RF front end of the proposed receiver is modeled in Verilog-AMS whereas the digital signal processing is implemented in Simulink-Matlab. The complete receiver has been verified to detect and process three different bands belonging to three different standards (GSM, UMTS, and WLAN) with the carrier frequency ranging from 0.9 to 2.5 GHz. Test signals with 4-QAM modulation, maximum bandwidth of 20 MHz, and input-dynamic range from –109 to –20 dBm is utilized to demonstrate the receiver performance including an EVM of –40 dB.     

Moving forward in retrodirective antenna arrays

Antenna arrays are individual radiating elements combined so that they function and perform like a single large antenna. Besides high radiating beam directionality, antenna arrays offer the capability to scan the main beam and control sidelobe radiation electronically. Retrodirective antenna arrays, as the name suggests, have a special feature. When receiving a signal from an unspecified direction, the array can automatically transmit a signal response to that same direction without any previous knowledge of the source direction. This function is performed automatically without the use of phase-shifters or digital circuitry. Compared to other array antennas that rely on digital signal processing (DSP) for beam direction control, this approach is much simpler and potentially faster because digital calculation is not needed. The automatic beam control nature of retrodirective arrays is well suited for RFID (radio frequency identification) and microwave tracking beacon applications. The article discusses the basic functionality as well as the ongoing research efforts and developments in retrodirective array architectures. Self-phasing attributes of different arrays are presented, as well as their applicability in practical communication systems.     

逆变系统中非线性负载谐波失真消除的DSP控制

对于非线性负载所引起的谐波失真，传统的逆变系统通常采用复杂的大规模无源元件滤波方案来滤除。本文介绍了一种采用DSP控制的逆变器和谐波调节系统的滤波方案，并分析了逆变系统中使用实时数字信号处理控制方法的优点。     

基于OMAP-L138平台SPI总线的嵌入式应用

数据的采集和控制是嵌入式应用领域的重点课题,随着数字转模拟器件精度的扩展和转换速率的提升,需要更加高效的运算平台和方法。PCM1702是一款高达20位分辨率的精密数字模拟转换器,其还具备超低失真、低噪声和快速电流输出等特性。SPI总线接口是嵌入式Linux系统中的典型应用,在高性能达芬奇平台OMAP L138处理器ARM+DSP双核环境下,通过GPIO实现SPI总线驱动,在高精度DA芯片PCM1702控制中得到应用。实验结果表明该驱动实现方法高效、稳定,具备针对精密器件的高速处理能力。     

High-precision voltage-measuring method using fast sampled data for electric power systems

Control and protection equipment in power systems requires higher sensitivity and operational reliability to meet today's changing power system requirements. The voltage-measuring deviation requirement for advanced voltage and var control equipment is less than 0.1 percent under conditions of harmonic distortion in the voltage waveform and power-system frequency variation. Studies on digital signal processing suitable for electric power systems showed that these requirements are satisfied using fast sampling and very fast 32-bit floating point operations by a Digital Signal Processor (DSP). This paper describes the design philosophy of a high-precision power system voltage-measuring method using fast sampled data. In addition, total voltage-measuring deviation characteristics under a combination of the techniques are described along with digital filter characteristics, frequency-measuring deviation characteristics, frequency variation versus gain-compensation characteristics of a digital filter, and peak value operating principles.