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19th IEEE Canadian Conference on Electrical and Computer Engineering

作者： Johnson, Thomas Sobot, Robert Stapleton, Shawn Simon Fraser Univ Sch Engn Sci 8888 Univ Dr Burnaby BC V5A 1S6 Canada Univ Western Ontario Fac Engn London ON N6A 5B9 Canada

ISBN: (纸本)9781424400379

Measurements of the coding efficiency and average transition frequency of a bandpass Sigma Delta modulator pulse train an shown. The parameters am important in RF class D amplifier applications and affect the power efficiency of the amplifier. A fourth order bandpass Sigma Delta modulator implemented in a SiGe process is used for experimentation and compared with simulated results.

关键词： bandpass sigma-delta modulation class D amplifier RF power amplifier coding efficiency

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An Evaluation of Three Representative 360-Degree Image Projection Formats in Terms of JPEG2000 coding efficiency 19

An Evaluation of Three Representative 360-Degree Image Proje...

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4th International Conference on Intelligent Information Technology (ICIIT)

作者： Hussain, Ikram Kwon, Oh-Jin Choi, Seungcheol Sejong Univ 209 Neungdong Ro Seoul South Korea

ISBN: (纸本)9781450366335

360-degree contents are becoming more popular nowadays since they create new and promising segments in entertainment, education, professional training, and other markets. These contents are spherical in nature and are mapped to a twodimensional representative plane using various projection formats. Due to the increased resolution to support the wide field of view, efficient compression of 360-degree content become crucial. The Joint Video Exploration Team (JVET) is investigating various projection formats, adapting to the input of existing video coding systems. Where it is of significant interest to see how different projection formats impact the compression efficiency of the 360-degree images. In this paper, we evaluate the performance of three well-known 360-degree image projection formats. Objective performance is evaluated by coding the 360-degree images projected on the two-dimensional representative plane using various projection formats such as equi-rectangular, cylindrical and cube-map projection format, with JPEG2000, a well-known still image coding standard. Our experimental results have proved that cubemap projection format is the appropriate solution considering the coding efficiency of JPEG2000.

关键词： 360-degree images objective assessment coding efficiency quality evaluation projection formats

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REFINING QP TO IMPROVE coding efficiency IN AVS

REFINING QP TO IMPROVE CODING EFFICIENCY IN AVS

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20th IEEE International Conference on Image Processing (ICIP)

作者： Li, Bin Xu, Jizheng Li, Houqiang Univ Sci & Technol China Hefei 230026 Peoples R China Microsoft Res Asia Beijing Peoples R China

ISBN: (纸本)9781479923410

This paper presents a Lagrange multiplier determination method and Quantization Parameter (QP) refinement algorithm used in the Rate-Distortion Optimization (RDO) process to improve the coding efficiency for Audio Video coding Standard (AVS) (IEEE 1857). This paper investigates the Lagrange multiplier setting problem for different kinds of pictures in the encoding process of AVS. When Lagrange multiplier is determined, to minimize the RD (Rate-Distortion) cost, the optimal QP can be selected by multiple-QP optimization. However, this kind of optimization increases the encoding time significantly. This paper analyzes the relationship between the QP value and Lagrange multiplier in this paper. And then this relationship is applied in the encoding process of AVS to refine the predetermined QP value. The experimental results show that proposed algorithm can lead to significant bit saving compared with the default anchor of AVS. The proposed method improves the coding efficiency without increasing the processing time.

关键词： Lagrange multiplier Quantization parameter AVS coding efficiency

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An empirical measurement of the coding efficiency in scalable video coding

An empirical measurement of the coding efficiency in scalabl...

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2nd International Conference on Geometric Modeling and Imaging

作者： Lopez, M. F. Ruiz, V. G. Garcia, I. Department of Computer Architecture and Electronics Spain

ISBN: (纸本)9780769529011

Video compression techniques can be classified into scalable and non-scalable. Scalable coding is more suitable in variable band-width scenarios because it improves the quality of the reconstructed video. On the other hand, the scalability has a cost in terms of coding efficiency and complexity This paper describes a JPEG2000-and-MCTF-based fully scalable video codec (FSVC) and analyzes a set of experiments to measure the cost of the scalability, comparing two different FSVC encoders, called open-loop FSVC and closed-loop FSVC. In the open-loop version of FSVC, the encoder uses the original images to make the predictions. The closed-loop version generates the predictions with reference images identical to those obtained by the decoder at a given bit-rate. Numerical and visual results demonstrate a small loss of the coding efficiency for the open-loop scheme. Moreover the inclusion of the closed-loop loop increases the complexity of the encoder and produces poor performance at high bit-rates.

关键词： scalable video coding coding efficiency JPEG 2000 MCTF video streaming

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Comparison of H.265 and VP9 coding efficiency for Full HDTV and Ultra HDTV Applications 25

Comparison of H.265 and VP9 Coding Efficiency for Full HDTV ...

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25th International Conference RADIOELEKTRONIKA

作者： Kufa, Jan Kratochvil, Tomas Brno Univ Technol SIX Res Ctr Dept Radio Elect Brno Czech Republic

ISBN: (纸本)9781479981175

This paper presents a performance comparison of the two modern video coding standards H.265/HEVC and VP9. For such comparison, the latest available versions of codecs for encoding were used. Comparison is provided by set of objective quality metrics. Comparing of coding efficiency is evaluated for Full HDTV and also for Ultra HDTV. Results indicate a dominance of HEVC encoding algorithm in comparison to VP9 if bit rates are set to higher values. In low bitrates results are both codecs very balanced with small dominance of VP9.

关键词： H.265 HEVC x265 VP9 webm video coding coding efficiency objectiv quality metrics Full HDTV Ultra HDTV

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Improving coding efficiency in grid-based hybrid video coding schemes

Improving coding efficiency in grid-based hybrid video codin...

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IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Heising, G Heinrich Hertz Inst Nachrichtentech Berlin GmbH Image Proc Dept D-10587 Berlin Germany

ISBN: (纸本)0780374029

In the past many grid-based video coding schemes using image warping prediction have been proposed. The advantage of grid-based motion compensation is its ability to model nontranslational motion. Disadvantages are the interdependency of motion vectors which require more complex motion estimation strategies and its restricted ability to model motion boundaries. In this paper different solutions to cope with the latter deficiency are presented and compared with respect to coding efficiency, In particular, three adaptive modes for handling motion discontinuities and a block-adaptive loop filtering are presented. It is shown that these are key components for achieving a high coding gain in grid-based hybrid coding. Introducing these features into a wavelet-based video coder leads to a coding gain of up to 2,5 dB compared to ITU H263+ and MPEG-4.

关键词： video coding transform coding motion compensation motion estimation adaptive filters coding efficiency grid-based video coding hybrid video coding image warping prediction motion compensation motion estimation block-adaptive filtering loop filtering wavelet-based coder coding gain ITU H.263+ MPEG-4

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coding efficiency and Bandwidth Enhancement in Polar Delta-Sigma Modulator Transmitter Using Quantization Noise Reduction and Parallel Processing Techniques

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JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS 2017年第5期26卷 1750085-1750085页

作者： Majd, Nasser Erfani Fard, Hassan Ghafoori Mohammadi, Abbas Shohadaye Hoveize Univ Technol Dept Elect Engn Susangerd Khouzestan Iran Amirkabir Univ Technol Tehran Polytech Dept Elect Engn Tehran Iran

This paper introduces an architecture to enhance coding efficiency (CE) and bandwidth of the delta-sigma modulator (DSM) transmitters. In this architecture a low-pass envelope DSM (LPEDSM) is used instead of the traditional Cartesian low-pass DSM (LPDSM) to reduce the quantization noise and to improve the coding efficiency. The simulation results show that for an uplink long-term evolution (LTE) signal with 1.92MHz bandwidth, 7.8 dB peak-to-average power ratio (PAPR), and an oversampling ratio (OSR) of 32, the CE for the polar LPEDSM transmitter is equal to 41.72% in comparison to 9.7% CE for the Cartesian LPDSM transmitter. In the next step, the CE and bandwidth of the transmitter are improved at the same time by using the quantization noise reduction technique in the polar LPEDSM transmitter with parallel baseband. By using this combined technique in the four-branch transmitter baseband part for an uplink LTE signal with 7.68MHz bandwidth, 7.8 dB PAPR, and an OSR of 32, the CE is improved from 42.59% to 55.86% with 40 dB signal-to-noise-and-distortion ratio (SNDR) while the clock speed is only 61.44MHz which is four times lower than the clock speed requirement of the conventional transmitter baseband part to achieve the same SNDR.

关键词： Delta-sigma modulator coding efficiency signal-to-noise-and-distortion ratio power amplifier parallel processing

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A 5-Level Discrete-Time Power Encoder with Measured coding efficiency of 70% for 20-MHz LTE Digital Transmitter

A 5-Level Discrete-Time Power Encoder with Measured Coding E...

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IEEE MTT-S International Microwave Symposium (IMS)

作者： Zhu, Qiuyao Ma, Rui Duan, Chunjie Teo, Koon Hoo Parsons, Kieran MERL Cambridge MA 02319 USA IIT Chicago IL 60616 USA

ISBN: (纸本)9781479938698

This paper reports the recent development on power coding method of generating a 5-level intermediate frequency PWM-based high speed digital-RF bit train, which is used as the input switching signal for class-S digital RF power amplifiers in the digital transmitter. By introducing the discrete-time power coding process at an IF of around 60 MHz, digital transmitter at cellular bands then becomes feasible to implement with current FPGA technologies. It can lower the required sampling rate more than 10 times compared with RF carrier PWM. In addition, a linearizer is designed using a look-up-table to minimize the nonlinear coding effects of the power encoder. The demonstrator shows the state-of-the-art measured power coding efficiency of 70.47% and SNR> 30dB for a 20 MHz LTE signals with PAPR of 10.25 dB at 1.9 GHz with our proposed approach.

关键词： Digital transmitter software defined radio switch mode power amplifier coding efficiency gallium nitride pulse width modulation FPGA

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coding efficiency in nominal inflection: expectedness and type frequency effects

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LINGUISTICS VANGUARD 2021年第s3期7卷

作者： Naranjo, Matias Guzman Becker, Laura Univ Paris CNRS LLF Paris France Univ Freiburg Erlangen Germany

Since (Zipf, George Kingsley. 1935. The psychobiology of language: An introduction to dynamic philology. Cambridge, MA: MIT Press;Zipf, George Kingsley. 1949. Human behavior and the principle of least effort. Journal of Consulting Psychology 13(3)), it has been known that more frequent lexical items tend to be shorter than less frequent ones, and this association between the length of an expression and its frequency has been applied to various grammatical patterns (syntactic, morphological, and phonological) and related to predictability or expectedness in the typological literature. However, the exact interactions of frequency and expectedness, their effect on shortening, and the mechanisms involved, are still not well understood. This paper proposes the Form-Expectedness Correspondence Hypothesis (FECH), taking into account not only the frequency of expressions but their overall structure and distribution, and explores the FECH in the domain of nominal inflection from a quantitative perspective.

关键词： coding efficiency entropy form-expectedness correspondence hypothesis inflection morphology quantitative typology

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Improved coding-efficiency Two-Level Source Encoder for RF Switch-Mode Power Amplifiers

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS 2012年第10期59卷 618-622页

作者： Podsiadlik, Tomasz Dooley, John Farrell, Ronan Natl Univ Ireland Maynooth Ctr Telecommun Res Maynooth Kildare Ireland

A Sigma Delta-driven RF switch-mode power amplifier is inherently linear only when it has a two-level output. At the same time, a two-level output generates the largest amount of quantization noise. This brief analyzes the effect of nonequal level spacing in a three-level Sigma Delta output and provides a method for shaping the corresponding error noise to regions outside the band of interest. Subsequently, the nonlinearity-shaping property is utilized to obtain an improved two-level drive signal based on three-level Sigma Delta modulation. The new binary drive signal is proven to have better adjacent channel leakage ratio and higher coding efficiency than a conventional two-level Sigma Delta modulator. In the investigated case, measured coding efficiency improves from 8.9% of the conventional two-level modulator to 21% of the modified two-level modulator.

关键词： coding efficiency sigma delta switch-mode power amplifier (SMPA)

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