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ERROR ANALYSIS OF A RAMP-TYPE PCM SOURCE ENcodeR FOR COLOR-TELEVISION SIGNALS

PROCEEDINGS OF THE INSTITUTION OF ELECTRICAL ENGINEERS-LONDON 1976年第7期123卷 662-666页

作者： WADE, JG PLYMOUTH POLYTECH SCH ELECT ENGNPLYMOUTH PL4 BAAENGLAND

The principle of an inherently simple 8-bit p.c.m. source encoder for video signals is briefly discussed, and a mathematical model of the encoder is developed. Parameters in the model are each assigned a normal probability law in order to simulate the inevitable, small random variations arising from component spreads and alignment error. Monte Carlo sampling of these parameters is then used to relate the degree of instrument error to the degree of chrominance nonlinearity suffered by a PAL colour television signal. The analysis indicates that voltage errors in the encoder should invariably fall within a half-quantum if chrominance nonlinearity is to be acceptable for broadcast quality signals.

关键词： Monte Carlo sampling ramp type PCM source encoder mathematical model colour television video signals Television and video equipment, systems and applications pulse-code modulation error analysis PAL colour television signals encoding

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6-BIT DPCM VIDEO SIGNAL-PROCESSING AND IMPLEMENTATION USING SYSTOLIC ARRAYS

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ELECTRONICS LETTERS 1990年第16期26卷 1225-1227页

作者： IBRAHIM, MK AGGOUN, A Department of Electrical and Electronic Engineering University of Nottingham Nottingham UK

A novel approach to increase the speed and reduce the hardware requirement of 2-D systolic convolvers for real-time video signal/image processing is proposed. This is achieved by coding video signals/images more efficiently using six-bit I-D DPCM coding. It is shown that using six-bit differential pulse-code modulation processing results in a 57% improvement in speed and a significant saving in the cost of 2-D systolic convolvers. The effect of quantisation errors on DPCM image convolution is also presented.

关键词： 6 bit modulation and coding methods two-dimensional digital filters Digital filters image processing systolic arrays DPCM image convolution cellular arrays pulse-code modulation encoding six-bit 1-D DPCM coding Optical information, image and video signal processing hardware requirement reduction quantisation errors computerised picture processing Computer vision and image processing techniques real-time processing six-bit differential pulse-code modulation processing DPCM video signal processing cost saving 2-D systolic convolvers improvement in speed

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STABILITY OF P.C.M.-OSCILLATOR SYNCHRONISATION SYSTEMS WITH SAMPLED ERROR SIGNALS

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ELECTRONICS LETTERS 1969年第9期5卷 183-&页

作者： MILLER, MR Institute of Engineering Control University of Warwick Coventry UK

Previous analyses of control-system stability have approximated the p.c.m. synchronisation system to a continuous linear model. The digital nature of the equipment indicates that a sampled model is more appropriate, and it is shown that, with this model, the system gains have to be reduced. A comparison between `continuous?? and `sampled?? stability criteria is made.

关键词： Control applications in telephony stability telephony oscillators pulse-code modulation modulation and coding methods Stability in control theory

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Delta-sigma waveguides for music synthesis

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COMPUTER MUSIC JOURNAL 1999年第4期23卷 33-47页

作者： Wallin, E Williams, RD Salinas, MH Lucent Technol Whippany NJ 07981 USA Univ Virginia Dept Elect Engn Charlottesville VA 22903 USA

Physical modeling of musical instruments has proven to be an interesting and useful technique for sound synthesis, because it provides the variability of real instruments. Natural dynamics can be captured in the model, yielding realistic emulation of traditional instruments. Model parameters can correspond to actual physical parameters so that parameter adjustment is intuitive, and these parameters can be adjusted to produce exotic new sounds. The digital waveguide (Smith 1992) is a computationally efficient method for the physical modeling of strings, drum heads, bores, and other resonant structures that appear in musical instruments. These waveguides can be implemented as a program running on a general-purpose computer which generates and stores sounds for later playback. Computers with sufficient capabilities can generate some of these sounds in real time for playing the sounds as they are produced. Alternately, special-purpose computer hardware can implement these waveguides to produce the sounds in real time. Recent work has introduced the possibility of digital hardware that can be reconfigured, and this alternative implementation may be particularly attractive for music synthesis. The reconfigurable hardware offers operating performance that approaches that of specialized, dedicated devices. However, the hardware can also be rearranged to implement different processing structures. The time required to rearrange the hardware is typically long with respect to the processing time while in any particular configuration, but this constraint appears to be consistent with typical music synthesis systems;that is, flexibility of synthesis is desired, but some delays can be tolerated to " patch" new sounds. The reconfigurable hardware does impose certain implementation constraints when compared with software emulations running on a general-purpose computer. These constraints are similar to those associated with any hardware implementation of physical models. This articl

关键词： WAVEGUIDES pulse-code modulation

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ZERO-CROSSING PRESERVATION IN LOW-BIT-RATE PSEUDORANDOMLY DITHERED QUANTIZATION OF SPEECH SIGNALS

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PROCEEDINGS OF THE INSTITUTION OF ELECTRICAL ENGINEERS-LONDON 1975年第2期122卷 119-123页

作者： CHEN, M TURNER, LF IMPERIAL COLL SCI & TECHNOL DEPT ELECT ENGNEXHIBITION RDLONDON SW7 2BTENGLAND

In earlier investigations, it has been found that, at low bit rates, the dithered quantisation of speech samples in pulse-code modulation (p.c.m.) is perceptually pleasing but is less intelligible than normal fixed-level quantised p.c.m. Also, it has been suggested that a possible cause of the reduced intelligibility of the dithered p.c.m. is the effect that the dithering has on the zero crossings of the speech signal. This paper reports on an investigation into this suggestion. A number of methods of dithered quantisation are considered in which the zero crossings of the speech signal are preserved, and the results of intelligibility tests carried out to compare the various methods of dithering are presented. The statistical analysis of the results shows that, for 3, 4 and 5 bits per sample quantisation, two of the methods of dithered quantisation are significantly more intelligible than normal, correspondingly low-bit-rate p.c.m., and the advantage is better than 1 bit per sample.

关键词： digital communication systems zero crossing preservation pseudorandomly dithered quantisation of speech signals low bit rate voice communication Speech and audio signal processing pulse-code modulation speech intelligibility pulse code modulation

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LINEAR pulse DISTORTION EFFECTS IN APPLICATIONS OF SEMICONDUCTOR OPTICAL AMPLIFIERS TO LOCAL-NETWORK

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ELECTRONICS LETTERS 1989年第9期25卷 618-619页

作者： ZENTENO, LA Polaroid Corp. Cambridge MA USA

It is shown that residual facet reflectivity in travelling-wave semiconductor optical amplifiers causes cumulative pulse broadening and distortion, hence limiting the maximum number of amplifiers that may be reliably used in a local network. For a TDM network, closed-form expressions are derived for this number in terms of bit rate and amplifier and pulse parameters.

关键词： LAN PCM TDM network bit rate closed-form expressions cumulative pulse broadening digital communication systems linear pulse distortion effects local area network local area networks local network optical communication optical communication optical links optical links pulse parameters pulse-code modulation residual facet reflectivity semiconductor junction lasers semiconductor lasers semiconductor optical amplifiers time division multiplexing travelling-wave

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PROGRAMMABLE SPLICE-FREE QUASI-MONOLITHIC 2 GBIT/S OPTICAL FIBER pulse code GENERATOR

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ELECTRONICS LETTERS 1990年第20期26卷 1673-1675页

作者： KIRKBY, CJG REID, DCJ JOU, DC PCO INC CHATSWORTHCA 91311

A mechanically programmable optical fibre lattice pulse code generator, implemented in a quasi-monolithic, splice-free polished coupler technology, has been designed, constructed and characterised. The prototype system permits the generation of reconfigurable four bit pulse sequences with a pulse repetition rate of 2 GHz, i.e. 500 ps interval within the pulses in the output train.

关键词： 1.3 micron 2 Gbit/s four bit pulse sequences optical communication equipment optical couplers optical fibres output train programmable optical fibre lattice pulse code generator prototype system pulse generators pulse repetition rate pulse-code modulation quasi-monolithic splice-free polished coupler technology

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pulse swallow frequency divider with idle DFFs automatically powered off

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ELECTRONICS LETTERS 2012年第11期48卷 636-638页

作者： Gao, Haijun Sun, Lingling Liu, Jun Hangzhou Dianzi Univ Minist Educ Key Lab RF Circuits & Syst Hangzhou 310038 Zhejiang Peoples R China

A pulse swallow frequency divider with ultra-low power consumption is presented. The D flip-flops (DFFs) in the prescaler and the swallow counter are controlled by the modulus control signal and are automatically powered off when they have no contribution to the operation of the divider. Implemented in SMIC 65nm CMOS process, the proposed divider can operate from 0.6 to 4.2 GHz, and the power consumption is 1.35 mW when operating at 2.4 GHz.

关键词： FREQUENCY dividers FLIP-flop circuits COMPLEMENTARY metal oxide semiconductors ELECTRONIC pulse techniques pulse-code modulation

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DETERMINATION OF OPTIMUM RECONSTRUCTION LEVELS FOR EMBEDDED DEcodeRS

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ELECTRONICS LETTERS 1994年第21期30卷 1737-1738页

作者： LOCKHART, GB ZHANG, SD Dept. of Electron. & Electr. Eng. Leeds Univ.

An iterative technique is described for computing optimum decoder reconstruction levels from input statistics given from 1 to R received bits per sample of the output of an R-bit per sample linear PCM encoder. Simulation of a DPCM embedded coding scheme with speech input shows that significant SNR gains are possible by using optimum reconstruction levels for decoding the supplementary bit stream.

关键词： SPEECH CODING pulse-code modulation

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PRACTICAL REAL-TIME PWM MODULATORS - AN ASSESSMENT

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IEE PROCEEDINGS-B ELECTRIC POWER APPLICATIONS 1992年第2期139卷 96-102页

作者： HANDLEY, PG BOYS, JT UNIV AUCKLAND DEPT ELECT & ELECTR ENGNAUCKLANDNEW ZEALAND

Many techniques have been proposed for generating PWM waveforms for controlling AC motor drives. This paper demonstrates the practicality of generating real-time, software-based PWM waveforms using low-cost microprocessors. It uses a space vector methodology and extends the concept of a computationally efficient trapezoidal modulation strategy to more desirable sinusoidal schemes. Within the algorithm, the apportioning of null (zero) voltage vector times (during which all three output phases are equal) is identified as a degree of freedom which can be used to optimise the resultant PWM waveform. The optimisation criterion chosen here was that of minimum motor harmonic losses. The traditional space vector modulation technique, which divides the null voltage vector times equally between the two possible null states, is shown to surpass both the triangulation and the bus-clamping generation strategies when evaluated in terms of both this criterion and other practical factors.

关键词： pulse-code modulation INDUCTION MOTORS

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