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Digital Signal Processing (digital + signal_processing)
Selected AbstractsReviews and New Releases: Digital Signal Processing of Signals: Theory and PracticeEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2000Maurice BellangerArticle first published online: 12 SEP 200 No abstract is available for this article. [source] Organizational evolution of digital signal processing software developmentJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 4 2006Susanna Pantsar-Syväniemi Abstract A base station, as a network element, has become an increasingly software-intensive system. Digital signal processing (DSP) software is hard real-time software that is a part of the software system needed in a base station. This article reports practical experiences related to organizing the development of embedded software in the telecommunication industry, at Nokia Networks. The article introduces the main factors influencing the development of DSP software and also compares the evolutionary process under study with both selected organizational models for a software product line and a multistage model for the software life cycle. We believe it is vitally important to formulate the organization according to the software architecture, and it is essential to have a dedicated development organization with long-term responsibility for the software. History shows that without long-term responsibility, there is no software reuse. In this paper we introduce a new organizational model for product line development. This new hybrid model clarifies long-term responsibilities in large software organizations with hundreds of staff members and formulates the organization according to the software architecture. Our case needs a couple more constraints to keep it in the evolution stage of the software life cycle. Thus, we extend the evolution phase in the multistage model to make it relevant for embedded, hard real-time software. Copyright © 2006 John Wiley & Sons, Ltd. [source] 8 Tb/s long haul transmission over low dispersion fibers using 100 Gb/s PDM-QPSK channels paired with coherent detectionBELL LABS TECHNICAL JOURNAL, Issue 4 2010Jérémie Renaudier 100Gb/s end-to-end broadband optical solutions are attractive to cope with the increasing demand for capacity. Polarization-division-multiplexed (PDM) quaternary-phase-shift-keying (QPSK) paired with coherent detection has been found to be promising for upgrading optical legacy systems based on 50GHz wavelength slots thanks to its high spectral efficiency (2bit/s/Hz) and its tolerance to linear effects. One of the major concerns for the deployment of such a solution is the transmission reach, mainly limited by nonlinear effects. This limitation can be exacerbated over non-zero dispersion shifted fiber (NZDSF) due to low local chromatic dispersion of the transmission fiber. The aim of this paper is first to report on the benefits brought by combining coherent detection techniques with advanced modulation formats as compared to conventional direct detection schemes for optical fiber communications. Digital signal processing paired with coherent detection is described to point out the efficiency of a coherent receiver to combat noise and to mitigate linear impairments. We then report on nonlinear tolerance of 100 Gb/s coherent PDM-QPSK through an 8 Tb/s transmission over a dispersion-managed link based on low dispersion fibers. © 2010 Alcatel-Lucent. [source] Intermediate frequency zero-crossing detection of filtered MSK based on irregular samplingEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 7 2007Tobias Scholand Short range communication systems such as Bluetooth and DECT (Digital Enhanced Cordless Telecommunications) deploy Gaussian frequency shift keying (GFSK), which is a continuous phase modulation (CPM) scheme derived from minimum shift keying (MSK). Since these short range communication systems require low-cost transceiver structures, the development of appropriate receiver techniques has been a major research topic. Particularly, analogue limiter--discriminator--integrator (LDI) dump filtering techniques have received considerable attention. With the availability of digital signal processing (DSP), the digital implementation of LDI techniques has become increasingly attractive. In order to make LDI receivers more accessible, zero-crossing detection was proposed. First, the authors shall focus on the establishment of an appropriate mathematical discrete-time system model, taking bandlimiting receiver filters into account explicitly. This system model serves as the basis for the development of a multitude of digital zero-crossing detection techniques. Starting from this mathematical discrete-time system model, the authors shall focus on a novel, yet promising, approach to digital zero-crossing detection in the intermediate frequency domain, using irregular sampling instead of the commonly employed regular sampling. The novel detectors shall be termed zero-crossing decorrelation detectors (ZXDDs), because a decorrelating approach will be used. The authors shall present three different variants of the ZXDD. The performance of these ZXDD schemes has been analysed in simulations by the authors and obtained results shall be presented and compared to the performance of known LDI and zero-crossing detection based techniques. Copyright © 2007 John Wiley & Sons, Ltd. [source] Hyperchaotic signal generation via DSP for efficient perturbations to liquid mixingINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2009Zhong Zhang Abstract This paper presents the design, simulation, hardware implementation and an application in liquid mixing of some hyperchaotic circuits, based on the digital signal processing (DSP) technology. The hyperchaotic Chen's system is used as an example to show the system discretization and variable renormalization in the design process. Numerical simulation is given to verify the hardware signal generator. The implemented hardware of Chen's system generates outputs in good agreement with the numerical simulation. The hyperchaotic signal output from the DSP is applied to generate complex perturbations in liquid mixing experiments. Dye dispersion experiments show that the induced hyperchaotic motion effectively helps enhance the mixing homogeneity in the stirred-tank-based mixer in our laboratory. Copyright © 2008 John Wiley & Sons, Ltd. [source] Speech Watermarking: An Approach for the Forensic Analysis of Digital Telephonic Recordings,JOURNAL OF FORENSIC SCIENCES, Issue 4 2010Marcos Faundez-Zanuy Ph.D Abstract:, In this article, the authors discuss the problem of forensic authentication of digital audio recordings. Although forensic audio has been addressed in several articles, the existing approaches are focused on analog magnetic recordings, which are less prevalent because of the large amount of digital recorders available on the market (optical, solid state, hard disks, etc.). An approach based on digital signal processing that consists of spread spectrum techniques for speech watermarking is presented. This approach presents the advantage that the authentication is based on the signal itself rather than the recording format. Thus, it is valid for usual recording devices in police-controlled telephone intercepts. In addition, our proposal allows for the introduction of relevant information such as the recording date and time and all the relevant data (this is not always possible with classical systems). Our experimental results reveal that the speech watermarking procedure does not interfere in a significant way with the posterior forensic speaker identification. [source] Coherent detection for spectral amplitude-coded optical label switching systemsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2010Alexey V. Osadchiy Abstract Coherent detection for spectrally encoded optical labels is proposed and experimentally demonstrated for three label tones spectrally spaced at 1 GHz. The proposed method utilizes a frequency swept local oscillator in a coherent receiver supported by digital signal processing for improved flexibility and upgradeability while reducing label detection subsystem complexity as compared with the conventional optical autocorrelation based approaches. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2732,2735, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25585 [source] | |||||||||||||