نتایج جستجو برای: level clipping

تعداد نتایج: 1084941  

2014
Yang Song Chaoshi Cai Jianping

Orthogonal frequency division multiplexing (OFDM) suffers from a high peak to average power ratio (PAPR). Tone reservation (TR) technology is considered as one of the most promising methods because of no additional distortion, no side information, and low implementation cost. However, in all PAPR reduction schemes,determining the optimal target clipping level is difficult. In this paper, we con...

Journal: :JNW 2014
Song Yang Feng Hu Chaoshi Cai

Orthogonal frequency division multiplexing (OFDM) suffers from a high peak to average power ratio (PAPR). Tone reservation (TR) technology is considered as one of the most promising methods because of no additional distortion, no side information, and low implementation cost. However, in all PAPR reduction schemes, determining the optimal target clipping level is difficult. In this paper, we co...

2013
Vaggam Srinivas Ravishankar Reddy

In this paper, the Peak-to-Average Ratio reduction in OFDM systems is implemented by the Adaptive Active Constellation Extension (ACE) technique which is more simple and attractive for practical downlink implementation purpose. However, in normal constellation method we cannot achieve the minimum PAR if the target clipping level is much below than the initial optimum value. To get the better of...

2002
Gavin Hill Michael Faulkner

This paper explores low complexity clipping of an Orthogonal Frequency Division Multiplexing (OFDM) transmit signal for critically sampled or oversampled complex data as a solution for the Peak to Average Power Reduction (PAPR) problem. Four existing clipping algorithms are compared to two new low complexity algorithms in an OFDM environment. Their performance is examined through mathematical a...

2014
Takahiro FUKUMORI Makoto HAYAKAWA Masato NAKAYAMA Takanobu NISHIURA Yoichi YAMASHITA

Development of communication systems allows people to easily record and distribute their speech. The clipping-noise, however, degrades the sound quality in the speech recording when gain level of input signals is excessive in the maximum range of an amplitude. In this case, it is necessary to suppress the clippingnoise in the observed speech for improving its sound quality. Although a linear pr...

بکرانی, مهدی , لطفی زاد, مجتبی ,

Stereophonic acoustic echo cancellation is one of the expanding areas in the field of the speech/multimedia communication systems. In a conventional stereophonic acoustic echo canceller, working in a stereo communication system, the existence of the strong cross-correlation between the input signals to the two channels has the problem of the low convergence speed of the weights of the adaptive ...

Journal: :The Journal of the Acoustical Society of America 2005
James M Kates Kathryn H Arehart

The speech intelligibility index (SII) (ANSI S3.5-1997) provides a means for estimating speech intelligibility under conditions of additive stationary noise or bandwidth reduction. The SII concept for estimating intelligibility is extended in this paper to include broadband peak-clipping and center-clipping distortion, with the coherence between the input and output signals used to estimate the...

2002
Aart J. C. Bik Milind Girkar Paul M. Grey Xinmin Tian

The MMXTM technology and SSE/SSE2 (streaming-SIMDextensions) introduced a variety of SIMD instructions that can exploit data parallelism in numerical and multimedia applications. In particular, new saturation and clipping instructions can boost the performance of applications that make extensive use of such operations. Unfortunately, due to the lack of support for saturation and clipping operat...

بصیری, مهدی , ولی, عباسعلی ,

Artemisia is the major component of the vegetation of a large portion of arid lands in Iran. Determining the utilization rate is an essential element in the management of these rangelands. Methods of determining the utilization regime for woody plants and shrubs include clipping and weighing, reference unit, ocular estimate, twig length, branch diameter and production index. These methods were ...

Journal: :iranian journal of neurology 0
zeinab taheri department of neurology, iranian center of neurological research, tehran university of medical sciences, tehran, iran. mohammad hosein harirchian department of neurology, iranian center of neurological research, tehran university of medical sciences, tehran, iran. hosein ghanaati department of radiology, advanced diagnostic and interventional radiology research center, tehran university of medical sciences, tehran, iran. alireza khoshnevisan department of neurosurgery, shariati hospital, tehran university of medical sciences, tehran, iran. payman salamati department of community medicine, sina trauma and surgery research center, tehran university of medical sciences, tehran, iran. mojtaba miri department of neurosurgery, imam khomeini hospital, tehran university of medical sciences, tehran, iran.

background: management of intracranial aneurysms has made debates about the best treatment modality in recent years. the aim of this study was to compare the interventional outcomes between two groups of patients, one treated with endovascular coiling and the other treated with surgical clipping. methods: this prospective study included 48 patients with intracranial aneurysms who underwent endo...

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