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Proceedings of the 1997 Data Compression Conference, DCC'97

作者： Seemann, Torsten Tischer, Peter Monash Univ Clayton Australia

The generalized Differential pulse code modulation is a powerful technique for creating adaptive compound predictors. The method works well over a large range of image types and pixel depths, contains no image-dependent thresholds, and can be easily modified for domains other than greyscale image data. Possible applications include RGB color images, 3-D volume imaging, image sequences, and sound.

关键词： pulse code modulation

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Eight channel PCM data formatter

Eight channel PCM data formatter

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Proceedings of the 1997 International Telemetering Conference, ITC/USA

作者： Kirk, William S. Kirkpatrick, Shawn Mussemann, Evan Inter-Coastal Electronics Inc Mesa United States

Advancing technology continually generates larger quantities of data at increasingly high transfer rates which fuels the need for instrumentation to take up the challenge of efficiently managing the collection of data. This defines the driving force behind the desire for increased channel capacity of PCM data formatters. By incorporating state-of-the-art Digital Signal Processing (DSP) technology coupled with high-performance Field Programmable Gate Arrays (FPGA), Inter-Coastal Electronics has designed the IF-810, a PCM data formatter. The IF-810 allows eight channels of PCM data, one voice channel and an InterRange Instrumentation Group (IRIG)-B channel to be combined and formatted for recording onto the TEAC RX-800 series recorders using a Hi8 8 mm video cassette as the recording media. During playback, the IF-810 clocks the PCM data out using a reconstructed version of the input clock. With this unique design, the PCM data and clock outputs are input directly to a decommutator which eliminates the need for costly bit-synchronizers. This paper discusses the integration of the DSP, FPGA and buffering techniques into a low-cost and efficient multi-channel PCM data formatter that accommodates high data rate inputs, all without the need of a bit-synchronizer for decommutation.

关键词： pulse code modulation

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Complexity of PCM formatting

Complexity of PCM formatting

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Proceedings of the 1997 International Telemetering Conference, ITC/USA

作者： Jones, Charles H. Gardner, Lee S. 412th TW/TS Edwards AFB United States

How difficult is it to develop a pulse code modulation (PCM) stream data format? Specifically, given a size, in bits, and a set of parameter sample rates, how hard is it to find a mapping of the sample rates that fits into the frame size - if one even exists? Using telemetry trees this paper will show that the number of possible mappings for a given set of parameters and sample rates grows exponentially in terms of the number of parameters. The problem can thus be stated in terms of finding a specific instance, or showing that no such instance exists, among an exponentially large number of potential mappings. Although not proof, this provides strong evidence that the PCM format design problem is NP-complete (meaning it is a member of nondeterministic polynomial space but not a member of deterministic polynomial space). That is, that the problem can not be solved in polynomial time and would take a computer years or centuries to solve relatively small instances of the problem. However, if the problem requirements are relaxed slightly, telemetry trees can be used to reduce the PCM formatting problem to linear time in terms of the number of parameters. This paper describes a technique that can provide an optimal and fully packed PCM format.

关键词： pulse code modulation

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Barker code position modulation for high-rate communication in the ISM bands

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Bell Labs Technical Journal 1996年第2期1卷 21-40页

作者： Bar-David, Israel Krishnamoorthy, Rajeev Wireless Technol. Res. Department Bell Labs. Holmdel NJ United States

This paper describes a new modulation and transmission scheme known as Barker code position modulation (BCPM). It can be used either in frequency bands in which spectral spreading is obligatory (such as the industrial, scientific, and medical [ISM] bands) or in cases in which it might be desirable due to other considerations. The use of BCPM to communicate enables systems to increase the transmitted data rate considerably. In the example discussed in this paper, the data rate is quadrupled from 2 to 8 Mb/s. Algorithms to decode BCPM signals efficiently in the presence of inter-symbol interference are also described. These may be applied to decoding a class of orthogonal and quasi-orthogonal signals. They can also be used to construct optimal and suboptimal receiver structures for systems using such signals to communicate over dispersive channels.

关键词： pulse code modulation

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Design of power control mechanisms with PCM realization for the uplink of a DS-CDMA cellular mobile radio system

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1996年第3期45卷 522-530页

作者： Chang, CJ Lee, JH Ren, FC NATL CHIAO TUNG UNIV CTR TELECOMMUN RESCOLL ELECT ENGN & COMP SCIHSINCHU 300TAIWAN

Power control (PC) is an important issue in a direct sequence-code division multiple access (DS-CDMA) cellular mobile radio system. Higher link performance and greater system capacity cannot be achieved unless an appropriate PC mechanism is employed. In previous research, a delta-modulation (DM) realization of strength-based and SIR-based PC mechanisms for uplink communication has been studied by simulation. In order to obtain higher PC trackability, in this paper we study a pulse-code-modulation (PCM) realization of the above two PC mechanisms for the uplink of a DS-CDMA cellular mobile radio system. The simulation results presented here indicate that PC mechanisms with PCM realization for the uplink can achieve a lower outage probability and thus higher link performance than PC mechanisms with DM realization. We also obtain optimal design parameters such as the stepsize and the control mode for the two PCM PC mechanisms. In addition, we compare the two PCM PC mechanisms in terms of their outage probability and stability and find that the strength-based mechanism has a higher outage probability but greater stability than the SIR-based mechanism.

关键词： cellular radio channel capacity code division multiple access power control probability pseudonoise codes pulse code modulation radio links spread spectrum communication telecommunication control telecommunication network reliability DS-CDMA cellular mob Channel capacity up link Radio systems Radio links pseudonoise codes pulse code modulation telecommunication network reliability Spread spectrum communication Personal computers Probability Power control code division multiple access Communication and control cellular radio mobile cellular radio

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Fidelity of phase-conjugated beams in a four-wave mixing set-up using Bi12TiO20-crystals

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JOURNAL OF MODERN OPTICS 1996年第7期43卷 1525-1533页

作者： Kiessling, A Baade, T Wenke, L Institute of Applied Optics Friedrich-Schiller-Universitat Jena Max-Wien-Platz 1 07743 Jena Germany

The quality of the aberration compensation provided by phase-conjugating mirrors (PCMs) is important for applications in lensless imaging or interferometry. In many cases an accuracy of a tenth of the wavelength for the phase reversal is sufficient. It will be shown that both the Fourier fringe evaluation method and a lensless image projection technique are useful to characterize the fidelity of phase conjugation with BaTiO3. A quantitative evaluation of the fidelity is given for four-wave mixing in Bi12TiO20 and self-pumped PCM with BaTiO3.

关键词： Four wave mixing phase conjugation Deci interferometry Fidelity BEAM pulse code modulation Bismuth titanate

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Thermal protection characteristics of a vertical rectangular cell filled with PCM air layer

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HEAT AND MASS TRANSFER 1996年第3期31卷 191-198页

作者： Ho, CJ Chu, CH Department of Mechanical Engineering National Cheng Kung University Tainan Taiwan 70101 Republic of China

The present paper presents a numerical analysis concerning thermal protection characteristics of a vertical rectangular composite cell filled with a solid-liquid phase change material (PCM) and air layer. Inside the composite cell the PCM layer is separated from air layer by a solid partition of negligible thickness. The buoyancy-induced flows developed in both the air-filled layer and the molten PCM zone inside the PCM layer were modeled as two-dimensional laminar Newtonian fluid flow adhering to the Boussinesq approximation. Meanwhile, two-dimensional conduction heat transfer was accounted for the unmelted solid PCM region. Delineation is made via a parametric simulation of the effects of the pertinent parameters: Ste (Stefan number), Sc (subcooling factor), Ra (Rayleigh number), aspect ratio of composite cell, A, and relative thickness ratio A(p)/A(a), on the transient thermal protection performance of the composite cell. Results demonstrate that by means of the latent-heat absorption inside the PCM layer, heat penetration across the composite cell can be greatly retarded over an effective duration until a critical instant until the melting front of PCM reaches the partition wall. Such an effective thermal protection duration is found to be a strong function of Ra, Ste, A(p)/A(a), and A. In addition, the results of the transient heat transfer rate penetrating through the composite cell are examined as a function of the pertinent parameters of the problem.

关键词： air layering pulse code modulation rectangular cell Composites thermal protection

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Bit-stream-arranged weighted modulation scheme for frequency selective fading channels.

Bit-stream-arranged weighted modulation scheme for frequency...

引用

IEEE GLOBECOM 1996 - Communications: The Key to Global Prosperity

作者： Kobayashi, K Kubota, S NTT Wireless Systems Lab Kanagawa-ken Japan

ISBN: (纸本)0780333365;0780333373

This paper proposes a bit-stream-arranged weighted modulation scheme to improve voice quality in frequency selective fading channels. The proposed modulation scheme employs an input bit stream arrangement method which changes the bit stream order for important bits so that they do not adjoin each other over time and a mapping method which controls the amplitude of modulation signals according to the importance of the bits, Computer simulations clarify that the proposed bit-stream-arranged weighted modulation scheme shows a noise reduction of 7 dB in voice signal compared with the conventional pi/4-shift DQPSK modulation scheme.

关键词： pulse code modulation

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DIGITAL AUDIO DATA-COMPRESSION

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ELECTRONICS & COMMUNICATION ENGINEERING JOURNAL 1995年第1期7卷 5-10页

作者： WYLIE, F

Conventional digital audio, as used for instance on compact discs, requires a large bandwidth for transmission and enormous amounts of storage space. Developments in high-speed digital signal processing chips have made it practical to reduce these requirements by employing sophisticated data compression techniques which reduce redundant and irrelevant information in the source signal. The paper reviews the types of digital audio data compression coders that are now available, their applications and the principles involved.

关键词： audio coding source signal data compression digital signals audio coders storage space high-speed digital signal processing chips codes Audio equipment and systems bandwidth Signal processing and detection pulse code modulation compact discs digital audio data compression

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PRIORITIZED STATISTICAL MULTIPLEXING OF PCM SOURCES

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IEEE-ACM TRANSACTIONS ON NETWORKING 1995年第5期3卷 549-559页

作者： CHAN, MH PRINCEN, JP THOMSON CONSUMER ELECTR R&D LABS CULVER CITYCA SILICON GRAPH MT VIEWCA 94043

Using simple multiplexer models, the performances of two prioritization mechanisms for the transmission of PCM coded signals modeled as exponential on/off sources are investigated and compared with nonprioritized transmission using statistical multiplexing and peak allocation, In both mechanisms the source traffic is partitioned into a low-priority stream and a high-priority stream, In the first approach independent channels of different quality of service are used to transport the two-priority streams. In the second approach a single channel is used in conjunction with a selective packet discarding procedure which attempts to restrict loss to the low-priority traffic, For a given source partitioning, new formulae are given to describe the average loss ratio for the low- and high-priority traffic. The effect of loss on quality for PCM coded signal is quantified by a new formula which relates signal-to reconstruction-noise ratio to low- and high priority loss. The results of the investigation show that both methods of prioritized transmission can provide significant improvements in overall service quality when the channel utilization is high.

关键词： Multiplexing Packet Switching pulse code modulation modulation Coding Telecommunication Traffic Losses Multi Access Systems Telecommunication Channels Prioritized Statistical Multiplexing PCM Sources Multiplexer Models Performances Prioritization Mechanism PCM coded Signals Exponential On Off Sources Peak Allocation Source Traffic Low Priority Stream High Priority Stream Two Priority Streams Packet Discarding Procedure Loss Signal To Reconstruction Noise Ratio Service Quality Channel Utilization Phase Change Materials Bit Rate Quality Of Service Probability Capacity Planning Multiplexing Traffic Control Intserv Networks Asynchronous Transfer Mode Source Coding

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