نتایج جستجو برای: fourier transform spectrum

تعداد نتایج: 354752  

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 ...

1995
B. Widrow M. Ball J. M. McCool S. S. Narayan A. M. Peterson M. J. Narasimha

| Based on the least mean squares (LMS) algorithm , the LMS spectrum analyzer can be used to re-cursively calculate the discrete Fourier transform (DFT) of a sliding window of data. In this paper, we compare the LMS spectrum analyzer with the straightforward non-adaptive implementation of the recursive DFT. In particular , we demonstrate the robustness of the LMS spectrum analyzer to the propag...

Journal: :Physical review letters 2007
Zhimin Shi Robert W Boyd Ryan M Camacho Praveen K Vudyasetu John C Howell

We describe a new type of Fourier transform (FT) interferometer in which the tunable optical delay between the two arms is realized by using a continuously variable slow-light medium instead of a moving arm as in a conventional setup. The spectral resolution of such a FT interferometer exceeds that of a conventional setup of comparable size by a factor equal to the maximum group index of the sl...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده فنی 1393

asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...

2008

Many attempts have been made to automate the process through which vibration signals are analyzed to pinpoint a machine fault. Detailed diagnostic vibration analysis is often performed using portable spectrum analyzers that implement Fast Fourier Transform (FFT) mathematics on the vibration signal. In some instances, only a trained analyst can interpret the vibration data, effectively diagnose ...

Journal: :AJR. American journal of roentgenology 2008
Thomas A Gallagher Alexander J Nemeth Lotfi Hacein-Bey

OBJECTIVE The Fourier transform, a fundamental mathematic tool widely used in signal analysis, is ubiquitous in radiology and integral to modern MR image formation. Understanding MRI techniques requires a basic understanding of what the Fourier transform accomplishes. MR image encoding, filling of k-space, and a wide spectrum of artifacts are all rooted in the Fourier transform. CONCLUSION Th...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد شاهرود - دانشکده مهندسی شیمی 1393

در این پژوهش نحوه ساخت نانوکامپوزییت eva/ag و اثر ضد میکروبی آن در درصدهای مختلف نانو ذره نقره مورد بررسی قرار گرفته است.نانوکامپوزیت حاصل از نطر شکل شناختی ، اندازه ذرات، ساختمان شیمیایی ، با استفاده از تستهای sem(scanning electrou microscopy)،tem (transmission electron microscope) ، xrd (x-ray fluorescence spectroscopy) ،ftir (fourier transform infrared spectroscopy) مورد ارزیابی قرار گرفت. د...

Journal: :Journal of Applied Mathematics and Physics 2013

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید