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time-domain algorithm FOR THE ESTIMATION OF 2 SINUSOIDAL FREQUENCIES

IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 1994年第1期141卷 33-38页

作者： MCCORMICK, WS LANSFORD, JL UNIV COLORADO COLORADO SPRINGSCO 80907

A computationally simple algorithm is presented that measures one or two frequencies using lookup tables and simple adders. The algorithm is based on a real-time processing of instantaneous frequency and envelope. The algorithm provides a maximum likelihood estimate in the single frequency case. Oversampling is required and the algorithm cannot estimate three or more frequencies. A complete error analysis is presented along with simulation results.

关键词： time domain algorithm SINUSOIDAL FREQUENCY ESTIMATION ERROR ANALYSIS

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A new time-domain frequency-selective quantification algorithm

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JOURNAL OF MAGNETIC RESONANCE 2002年第2期155卷 226-235页

作者： Romano, R Motta, A Camassa, S Pagano, C Santini, MT Indovina, PL Univ Naples Federico II Dipartimento Sci Fis Ist Nazl Fis Mat Unita Napoli I-80126 Naples Italy CNR Ist Chim Biomol I-80078 Naples Italy Ist Super Sanita Ultrastrutture Lab I-00161 Rome Italy

In this paper a new time-domain frequency-selective quantification algorithm is presented. Frequency-selective quantification refers to a method that analyzes spectral components in a selected frequency region, ignoring all the other components outside. The algorithm, referred to as MeFreS (Metropolis Frequency-Selective), is based on rank minimization of an opportune Hankel matrix. The minimization procedure is satisfied by the down-hill simplex method, implemented with the simulated annealing method. MeFreS does not use any preprocessing step or filter to suppress nuisance peaks, but the signal model function is directly fitted. In this manner, neither inherent signal distortions nor estimation biases to be corrected occur. The algorithm was tested with Monte Carlo simulations. A comparison with VARPRO and AMARESw algorithms was carried out. Finally, two samples of known content from NMR data were quantified. (C) 2002 Elsevier Science (USA).

关键词： frequency selective algorithm time domain algorithm quantification in NMR NMR spectroscopy

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Development of a Truck-Mounted Arc-Scanning Synthetic Aperture Radar

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2014年第5期52卷 2773-2779页

作者： Lee, Hoonyol Lee, Jae-Hee Kim, Kwang-Eun Sung, Nak-Hoon Cho, Seong-Jun Kangwon Natl Univ Dept Geophys Chunchon 200701 South Korea Korea Inst Geosci & Mineral Resources Taejon 305350 South Korea

This paper presents the development of a ground-based arc-scanning synthetic aperture radar (ArcSAR) system mounted on a truck. ArcSAR formulates synthetic aperture by a horizontal circular motion of antennas attached at the end of an extendable boom. The ArcSAR system is designed to operate in two different imaging modes: the spot mode and the scan mode. The spot mode obtains a high-resolution image by fixing the view angle of antennas toward a target. The scan mode obtains wider image coverage with a reduced resolution by fixing the antennas relative to the boom. Different SAR focusing algorithms were implemented for the accuracy and efficiency of image processing: the time domain algorithm for the spot mode and the range Doppler algorithm for the scan mode. An exemplary X-band ArcSAR spot mode image, obtained with a 180 degrees scanning of 4-m boom, has an azimuth resolution of 0.07 degrees, which is equivalent to the 12.6-m linear scanning of a conventional ground-based SAR system. An ArcSAR scan mode image was successfully obtained as well, covering a 350 degrees image area at an azimuth resolution of 1.07 degrees, which is 11 times better than that of arc-scanning real aperture radar that would have 11.84 degrees azimuth resolution.

关键词： Arc-scanning synthetic aperture radar (ArcSAR) range Doppler algorithm SAR scan mode spot mode time domain algorithm

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A novel algorithm for voltage transient detection and isolation for power quality monitoring

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ELECTRIC POWER SYSTEMS RESEARCH 2014年第Sep.期114卷 110-117页

作者： Moreno, Roberto Visairo, Nancy Nunez, Ciro Rodriguez, Elias Univ Autonoma San Luis Potosi Fac Ingn San Luis Potosi 78290 Mexico Inst Tecnol Celaya Dept Elect Celaya Mexico

Usually the measurement instruments dedicated to power quality assessment contain a transient detection stage that is activated only when it is necessary. However, it is common that such stage does not have the same sampling time than the stage devoted to measurements in steady state such as power factor, harmonic content or RMS values. In this paper, the authors describe a simple algorithm that can detect and isolate notches and impulsive transients from other voltage disturbances with the same sampling time used for measurements in steady state. The merit of this approach is that, if the proposed algorithm is set up in a power quality analyzer (PQA), this device will be able to record all kind of disturbances, the steady state ones using the classical algorithms programmed in the PQA and the transient ones by the approach addressed in this paper, the same sampling time considered for all of them, without substantial increase of the computational effort. The method was implemented in a prototype, and laboratory and industry results are shown. Additionally, operative limitations of the method are discussed. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Electric power quality Detection and isolation of disturbances Voltage transients Notches and impulsive transients time domain algorithm Isolation from steady state disturbances

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ON THE VLSI DESIGN OF A PIPELINE REED-SOLOMON DECODER USING SYSTOLIC ARRAYS

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IEEE TRANSACTIONS ON COMPUTERS 1988年第10期37卷 1273-1280页

作者： SHAO, HM REED, IS CALTECH JET PROP LABPASADENACA 91109 UNIV SO CALIF DEPT ELECT ENGNLOS ANGELESCA 90089

A novel VLSI design for a pipeline Reed-Solomon decoder is presented. The transform decoding technique used in a previous study is replaced by a time-domain algorithm through a detailed comparison of their VLSI implementations. An architecture that implements the time-domain algorithm permits efficient pipeline processing with reduced circuitry. Erasure correction capability is also incorporated with little additional complexity. By using multiplexing technique, an implementation of Euclid"s algorithm maintains the throughput rate with less circuitry. Some improvements result in both enhanced capability and significant reduction in silicon area, making it possible to build the decoder on a single chip

关键词： Cellular Arrays Decoding VLSI Erasure Correction Euclid algorithm VLSI Design Pipeline Reed Solomon Decoder Systolic Arrays Transform Decoding Technique time domain algorithm Multiplexing Technique Very Large Scale Integration Reed Solomon Codes Decoding Systolic Arrays Polynomials Pipeline Processing Circuits Computer Architecture algorithm Design And Analysis Throughput

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A Faster algorithm for Frequency Solving of Nonlinear Three-Phase Circuits

A Faster Algorithm for Frequency Solving of Nonlinear Three-...

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International Symposium on Fundamentals of Electrical Engineering (ISFEE)

作者： Tufan, Claudiu Vasilescu, George Marian Hantila, Ioan Florea Bordianu, Adelina Maricaru, Mihai Natl Univ Sci & Technol Politehn Bucharest Dept Electrotech Fac Elect Engn Bucharest Romania

ISBN: (纸本)9798350308570;9798350308563

The Hantila. Method is successfully used for solving nonlinear problems in electrical engineering, including nonlinear three-phase circuits. The method is highly versatile and allows the analysis of many harmonics. In this paper, we analyze a new approach to accelerate it. This involves modifying the algorithm by removing the computation of the Fourier series coefficients from the iterative cycle. This is achieved by calculating the transfer characteristic of the linear part of the algorithm. During an iteration computations are performed only in the time domain. The duration of an iteration is no longer affected by an increase in the number of analyzed harmonics. Thus, they can notably increase without significantly affecting the computation time.

关键词： Acceleration procedures Characteristic function Frequency domain solution Hantila method Nonlinear three-phase circuits Picard-Banach iterative solution time domain algorithm Thyristors Transfer characteristic

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Overview of Pixel Level Image Fusion algorithm

Overview of Pixel Level Image Fusion Algorithm

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International Forum on Computer and Information Technology (IFCIT)

作者： Li, Mingjing Dong, Yubing Li, Jie Changchun Univ Coll Elect & Informat Engn Changchun 130022 Peoples R China

ISBN: (纸本)9783038350194

Pixel level image fusion algorithm is one of the basic algorithms in image fusion, which is mainly divided into time domain and frequency domain algorithm. The weighted average algorithm and PCA (principal component analysis) are popular algorithms in time domain. Pyramid algorithm and wavelet algorithm are usually used to fuse two or multiple images in frequency domain. In this paper, pixel level image fusion algorithm was summarized, including of operation, characteristics and application etc. MATLAB simulation shows that effect of frequency domain algorithm is better than time domain algorithm. Evaluation criteria mainly refer to entropy, cross entropy, the mean and standard deviation etc. Evaluation standard is the reference of fusion effects, different evaluation criteria could be selected according to different fused image and different fusion purpose.

关键词： pixel level image fusion time domain algorithm frequency domain algorithm

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A Surface Grid Fast BP Method for Spaceborne SAR Imaging

A Surface Grid Fast BP Method for Spaceborne SAR Imaging

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2021 CIE International Conference on Radar, Radar 2021

作者： Chen, Quan Liu, Wenkang Sun, Guang-Cai Xing, Mengdao Bie, Bowen Xi'an China

ISBN: (纸本)9781665498142

In the previous spaceborne SAR imaging methods based on time domain algorithm, the imaging grids are usually arranged in a flat plane. However, for ultra-large width and ultra-high resolution imaging, the quadratic phase error caused by surface bending is large, which makes the images defocus. In this paper, the surface grid is arranged for accurate imaging, and a new two-step spectrum compression function is proposed to achieve sub-aperture images fusion. © 2021 IEEE.

关键词： spectrum compression surface bending time domain algorithm

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A variable chirp rate stepped frequency linear frequency modulation waveform designed to approximate wideband non-linear radar waveforms

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DIGITAL SIGNAL PROCESSING 2021年 109卷 102884-102884页

作者： Saleh, Mahdi Omar, Samir-Mohamad Grivel, Eric Legrand, Pierrick Bordeaux Univ Bordeaux INP ENSEIRB MATMECA IMS UMR CNRS 5218 Talence France Lebanese Univ Fac Sci 1 Dept Phys & Elect Beirut Lebanon Int Univ Beirut BIU Sch Engn CCE Dept Beirut Lebanon Bordeaux Univ IMB UMR CNRS 5251 INRIA Bordeaux France

The non-linear frequency modulation (NLFM) waveform is one of the existing waveforms that can be used in high range resolution radar applications. However, a high sampling frequency and consequently an expensive ADC are required. To overcome this drawback while taking advantage of the features of the NLFM waveform, we suggest approximating the wideband NLFM waveform by a piecewise linear waveform and using it in a stepped frequency (SF) framework. Thus, a variable chirp rate SF-LFM waveform is proposed where SF is combined with a train of LFM pulses having different chirp rates, durations, and bandwidths. In this paper, these parameters are derived from a tangent-based NLFM waveform. At the receiver, a generalized version of the time domain (TD) algorithm is proposed to process the received echoes. Our purpose is to obtain the high range resolution profile (HRRP) whose properties are of the same magnitude orders as those obtained using a tangent-based NLFM waveform. These properties are the peak sidelobe ratio, the integrated sidelobe, and the range resolution. Toward this goal, a multi-objective optimization issue is addressed to deduce the parameters of the proposed waveform by using two types of approaches based on evolutionary algorithms. Their relevance is compared. Our analysis and simulations show that the proposed approaches attain the targeted performance goals with a smaller sampling frequency at the receiver. (C) 2020 Published by Elsevier Inc.

关键词： Stepped frequency waveforms Piecewise NLFM time domain algorithm Multi-objective optimization Genetic algorithm NSGA-II

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