نتایج جستجو برای: signal resolution

تعداد نتایج: 676645  

A.Mahlooji Far, Hassan Ghassemian, Sayed Mahmoud Sakhaei,

Contrast resolution and detail resolution are two important parameters in ultrasound imaging. This paper presents a new method to enhance these parameters, simultaneously. A parallel auxiliary beamformer has been employed whose weightings are such that an estimation of the leaked signal through the main beamformer is obtained. Then the output of main beamformer is modified according to the ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده فنی و مهندسی 1390

magnetic resonance imaging (mri) is a notable medical imaging technique that makes of phenomenon of nuclear magnetic resonance. because of the resolution and the technology being harmless, mri has considered as the most desirable imaging technique in clinical applications. the visual quality of mri plays an important role in accuracy of medical delineations that can be seriously degraded by exi...

Journal: :رادار 0
رضا منصوری رضا محسنی

one of the most common signals used for achieving high range resolution in radar is stepped-frequency signals. when a target is stationary in these radars, dft (discrete fourier transform) based processing is used to attain high range resolution profile (hrrp). however, in the case of moving target, due to spreading of the echo signal spectrum, dft based processing is not optimal and decreases ...

علائی, محمد, امین داور, حمیدرضا ,

A new automatic target recognition algorithm to recognize and distinguish three classes of targets: personnel, wheeled vehicles and animals, is proposed using a low-resolution ground surveillance pulse Doppler radar. The Chirplet transformation, a time frequency signal processing technique, is implemented in this paper. The parameterized RADAR signal is then analyzed by the Zernike Moments (ZM)...

Alireza Sadremomtaz, Ebrahim Siri

Wavelet transformation is one of the most practical mathematical transformations in the field of image processing, especially image and signal processing. Depending on the nature of the multiresolution analysis, Wavelet transformation become more accessible and powerful tools. In this paper, we refer to the mathematical foundations of this transformation.   Introduction: The...

This paper presents an adaptive digital resolution improvement method for extrapolating and recursive analog-to-digital converters (ADCs). The presented adaptively enhanced ADC (AE-ADC) digitally estimates the digital equivalent of the input signal by utilizing an adaptive digital filter (ADF). The least mean squares (LMS) algorithm also determines the coefficients of the ADF block. In this sch...

This paper presents a new data compression method for current loop transmitters. In this method, the 4-20 mA current domain is divided into some equal pieces that are used for distinct data domain with a constant relative resolution, resulting in widening the signal span. This technique eliminated the need for high resolution ADC’s or DAC’s in communication of 4-20mA current loop signals. Furth...

Journal: :نشریه دانشکده فنی 0
احمد ثقفی دانشگاه صنعتی مالک اشتر سید مهدی فخرائی دانشگاه تهران منوچهر منطقی دانشگاه صنعتی مالک اشتر

ultra-wideband (uwb) radio is a promising technology for low-cost, high-rate communications at short ranges. however, high bandwidth and low power of the uwb signals impose some difficult challenges in signal processing and implementation of the receiver. acquisition of the signal timing is the first task to be performed in a coherent receiver. the high bandwidth of uwb signals demand for fine ...

Ahmad Saghafi Manoochehr Manteghi Seyyed Mehdi Fakhraee

Ultra-wideband (UWB) radio is a promising technology for low-cost, high-rate communications at short ranges. However, high bandwidth and low power of the UWB signals impose some difficult challenges in signal processing and implementation of the receiver. Acquisition of the signal timing is the first task to be performed in a coherent receiver. The high bandwidth of UWB signals demand for fine ...

The main purpose of this paper is to develop the method of characteristic functions for calculating the detection characteristics in the case of the object surrounded by rough surfaces. This method is to be implemented in synthetic aperture radar (SAR) systems using optimal resolution algorithms. By applying the specified technique, the expressions have been obtained for the false alarm and cor...

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