The use of pulse code modulation (PCM) in the junction and trunk areas of telephone and data transmission is discussed. The principal parameters of the basic junction system upon which international standardization is...
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The use of pulse code modulation (PCM) in the junction and trunk areas of telephone and data transmission is discussed. The principal parameters of the basic junction system upon which international standardization is now proceeding are reviewed. In addition, the error noise performance of the system is examined, and it is shown how this differs markedly from Frequency Division Multiplex systems.
In this paper a self-compensating pulse code modulation compound flow control valve and its self-compensating algorithm are introduced. After adopting a self-compensating method, the compound valve can maintain good c...
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In this paper a self-compensating pulse code modulation compound flow control valve and its self-compensating algorithm are introduced. After adopting a self-compensating method, the compound valve can maintain good control quality when one or more turn on/off valves (TOVs) fail by adjusting the activities of unfailed TOVs. A stochastic fault model for the compound valve is established and a Monte Carlo approach is used to calculate its life distribution. The results indicate that there is about 20-50% increase of mean controllable life. This might be of great importance when immediate emergency shutdown is not allowable or too costly, such as in the case of aircraft control and in the control of continuous processes. The extra life can leave a large enough time margin to plan a more graceful shutdown and maintenance. Copyright (C) 2006 John Wiley & Sons, Ltd.
The great impetus to the invention of pulse code modulation was the collateral development of microwave radio. However, by the time that pulse code modulation became a practical system for telephony, microwave radio h...
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The great impetus to the invention of pulse code modulation was the collateral development of microwave radio. However, by the time that pulse code modulation became a practical system for telephony, microwave radio has for good reasons developed along analog lines. There was however an obvious application for pulse code modulation on cable, which led to near-universal implementation on transmission routes and ultimately to the digital integrated network. Digital techniques spread back into radio systems only after widespread usage elsewhere, and much technical development to adapt them to the medium.
Characteristic features of pulse code modulation due to coding methods have been investigated, and a modulator with counting coder and a demodulator with feedback decoder were developed fluidically. A 3 bit equipment ...
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ISBN:
(纸本)0080316816
Characteristic features of pulse code modulation due to coding methods have been investigated, and a modulator with counting coder and a demodulator with feedback decoder were developed fluidically. A 3 bit equipment by commercially available devices proved that coding and decoding could be realized approximately less than 10 Hz of pneumatic signal. Characteristics of interpolation filter exert a considerable influence upon demodulation processes.
The paper describes the factors leading to the invention of p.c.m., and the form first devised by A.H. Reeves. It outlines the development of early p.c.m. telephone systems up to about 1960, with emphasis on developme...
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The paper describes the factors leading to the invention of p.c.m., and the form first devised by A.H. Reeves. It outlines the development of early p.c.m. telephone systems up to about 1960, with emphasis on developments of which the author has personal experience. It surveys the life and work of the inventor, including his later ideas on encoding. Finally, it brings to light a little-known precursor of p.c.m., a form of picture telegraph invented by P.M. Rainey in 1921.
This article proposes a space vector-based, pulse code modulation (PCM) scheme with reduced zero sequence voltage for an Open-End-Winding-Induction-Motor (OEWIM) fed by two-level inverters on both sides. A multilevel ...
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This article proposes a space vector-based, pulse code modulation (PCM) scheme with reduced zero sequence voltage for an Open-End-Winding-Induction-Motor (OEWIM) fed by two-level inverters on both sides. A multilevel inverter fed induction motor drive using Space Vector Sigma Delta modulation (SVSDM) can be considered to be an analogy of a digital communication system. In the proposed scheme, the nearest three space vectors to the integrated error vector of the sigma delta modulator form the Thiessen region. In the Thiessen region, the reference vector gets quantized to its closest space vector in a sampling period. This reduces spurious switching. The quantized space vector is encoded to ones and zeros corresponding to the ON and OFF states of the inverter switches. In the proposed PCM, redundant switching vectors with reduced Zero Sequence Voltage (ZSV) are selected in the three-level operation. This results in reducing the ZSV without a reduction in the DC bus utilization. The proposed PCM is verified on a 3 HP OEWIM that is supplied with power from 11.5 KVA two-level inverters on both ends. Results of comparing the performance of the proposed PCM with those of existing modulation schemes are presented.
This paper introduces a high-performance concealment algorithm for packetized PCM-coded speech as in ITU-T Recommendation G.711. The proposed prediction algorithm implements a combination of linear prediction model an...
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This paper introduces a high-performance concealment algorithm for packetized PCM-coded speech as in ITU-T Recommendation G.711. The proposed prediction algorithm implements a combination of linear prediction model and reverse-order replicated pitch period technique as implemented in the ITU-T G.711 Appendix A (ITUT Recommendation G. 117, November 2000). The new algorithm is compared to the ITU-T G.711 Appendix A standard and to the commercial tool of packet repetition. It is shown to produce better concealment quality in almost all cases. (C) 2003 Elsevier B.V. All rights reserved.
It has been shown that randomized Non-Return-to-Zero-Level code performs better than the other codes tested when the PCM data is bandpass-filtered and then summed with spectrally conditioned noise. These results apply...
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It has been shown that randomized Non-Return-to-Zero-Level code performs better than the other codes tested when the PCM data is bandpass-filtered and then summed with spectrally conditioned noise. These results apply to PCM bit synchronizers with ″good″ dc restorers. However, tests need to be run using several recorders to determine the effects under real-life conditions.
The appeal of PCM techniques is greatly enhanced by the availability of monolithic companders. The author reports on a recent development in this field.
The appeal of PCM techniques is greatly enhanced by the availability of monolithic companders. The author reports on a recent development in this field.
We report the implementation of a chemical neurostimulation technique using microfluidic devices. The microfluidic chip in this research is used for the in vitro study of the nervous system of Aplysia californica unde...
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We report the implementation of a chemical neurostimulation technique using microfluidic devices. The microfluidic chip in this research is used for the in vitro study of the nervous system of Aplysia californica under localized chemical stimulation. The polydimethylsiloxane (PDMS) device is a one-bit pulsecode modulator that digitally controls the concentration of the non-hydrolysable cholinergic agonist carbachol injected directly above a ganglion. The chip was successful in repeatedly and controllably inducing bursts of ingestive-like patterns. The ability of the chip to induce rhythmic activity through the sheath of the ganglion suggests that it could serve as the basis for an implantable, in vivo device to control neural activity and motor behavior using chemical stimulation. (C) 2010 Elsevier B.V. All rights reserved.
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