نتایج جستجو برای: تخمین snr

تعداد نتایج: 33164  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1390

رادیوی شناختی (cr) قادر است از طریق حسگری طیفی، حضور یا عدم حضور کاربران اصلی باند فرکانسی مورد نظر را آشکارسازی نموده و از اطلاعات حاصله در جهت بهره برداری فرصت طلبانه از طیف استفاده نماید. مهم ترین چالش در این زمینه، احتمال عدم آشکارسازی صحیح حضور کاربران اصلی طیف می باشد. روش های مختلفی برای حسگری طیفی پیشنهاد شده است. بیشتر پژوهش های انجام شده در ارتباط با آشکارسازی انرژی (ed) است. این در ح...

Journal: :auditory and vestibular research 0
javad hanilou department of audiology, school of rehabilitation, tehran university of medical sciences, tehran, iran jamileh fatahi department of audiology, school of rehabilitation, tehran university of medical sciences, tehran, iran and department of audiology, school of rehabilitation sciences, iran university of medical sciences, tehran, iran ali akbar tahaei department of audiology, school of rehabilitation sciences, iran university of medical sciences, tehran, iran shohreh jalaie biostatistics, school of rehabilitation, tehran university of medical sciences, tehran, iran

background and aim : the quick speech in noise (q-sin) test have been designed to evalu­ate individuals’ ability to recognize speech in noise. this study established to evaluate the test-retest reliability and equivalency of the five test lists of the persian q-sin test in subjects with sensory hearing loss (shl) and normal hearing individuals. methods : this cross-sectional study was per­forme...

2005
Markus A. Dangl Jürgen Lindner

We consider turbo equalization of ISI channels for the practically relevant case when neither channel state information nor SNR knowledge is perfect at the receive side. In particular, we investigate the influence of imperfect (uncertain) training information on the performance of several known SNR estimation algorithms. Numerical results indicate that uncertain training data causes an addition...

2003
Jian Sun Matthew C. Valenti

Turbo codes are sensitive to both (timing) synchronization errors and signal-to-noise ratio (SNR) mismatch. Since turbo codes are intended to be deployed in environments with very low SNR, conventional synchronization methods often fail. This paper introduces a solution for jointly estimating the SNR and achieving timing synchronization based on the statistics of the received signal. Simulation...

2004
M. Simon S. Dolinar

A method by which a popular signal-to-noise ratio (SNR) estimator can be reconfigured to yield improved performance is proposed. The reconfiguration consists of partitioning the symbol interval into a larger (but even) number of subdivisions than the two that have been traditionally suggested for this estimator but still processing the observables in successive pairs. The optimum number of subd...

Journal: :CoRR 2008
Zouheir Rezki David Haccoun François Gagnon

The capacity of a discrete-time memoryless channel, in which successive symbols fade independently, and where the channel state information (CSI) is neither available at the transmitter nor at the receiver, is considered at low SNR. We derive a closed form expression of the optimal capacity-achieving input distribution at low signal-to-noise ratio (SNR) and give the exact capacity of a non-cohe...

2011
CHAO GONG BANGNING ZHANG AIJUN LIU DAOXING GUO Chao GONG Bangning ZHANG Aijun LIU Daoxing GUO

Signal to noise ratio (SNR) estimators are required for many radio engineering applications. In this paper, a SNR estimator based on the first and second order moments is derived and examined for constant envelope modulations over additive white Gaussian noise (AWGN) channel. Firstly, a modification method is proposed to reduce the bias of conventional first and second order moments based SNR e...

Journal: :Journal of neurophysiology 1997
M C Sañudo-Peña J M Walker

The effect of cannabinoids on the excitatory input to the substantia nigra reticulata (SNr) from the subthalamic nucleus was explored. For this purpose a knife cut was performed rostral to the subthalamic nucleus to isolate the subthalamic nucleus and the SNr from the striatum, a major source of cannabinoid receptors to the SNr. The data showed that the cannabinoid agonist WIN55,212-2 blocked t...

1999
C. De Vleeschouwer B. Macq

In this paper, SNR scalable representations of video signals are studied. The investigated codecs are well suited for communications applications because they are all based on backward motion-compensated predictive coding, which provides the necessary low-delay property. In a Very-Low Bit Rate context (VLBR), the Matching Pursuits signal representation algorithm is used to represent the Displac...

2006
Xu Shao Jon Barker

This paper examines the problem of estimating stream weights for a multistream audio-visual speech recogniser in the context of a simultaneous speaker task. The task is challenging because signalto-noise ratio (SNR) cannot be readily inferred from the acoustics alone. The method proposed employs artificial neural networks (ANNs) to estimate the SNR from HMM state-likelihoods. SNR is converted t...

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