最新刊期
卷 41 ， 期 9 ， 2013
- 摘要：The combination of frequency modulated continuous wave(FMCW)and synthetic aperture radar(SAR)leads to the rapid development of the compact,low-cost,low power imaging sensors.The model of imaging in the presence of motion error is presented firstly,based on which the difference of motion compensation between FMCW SAR and pulsed SAR is compared.The integrated processing flow of motion compensation is proposed,contains the compensation along track and in the line of sight.The experimental FMCW SAR data and focused SAR images verify the feasibility of the proposed method.关键词：frequency modulated continuous wave;synthetic aperture radar;motion compensation;range Doppler;frequency scaling2|1667|4更新时间：2025-07-16
- 摘要：According to the spectrum sensing problem under low signal-noise ratio (SNR) and dynamic noise in cognitive radio(CR)networks,this paper introduced nonlinear stochastic resonance(SR)of physics into spectrum sensing,and proposed an energy detection(ED)based on generalized stochastic resonance(GSR).For the proposed algorithm,SR noise was added to make nonlinear system,signal and noise matched,which modifies the probability distribution of the detection statistics,and confirms the existence of the signal effectively.This paper drive the probability density unction(PDF)of matched noise,and get some significant conclusions about the performance,effect of noise uncertainty and sensing time of the proposed algorithm.The simulation results validate the theory,and show that the proposed algorithm can improve the performance of existing energy detection at least 3dB under low SNR.The proposed algorithm also has less sensing time,low complexity and can effectively overcome the influence of the noise uncertainty.关键词：spectrum sensing;stochastic resonance;energy detection;low SNR;noise uncertainty2|2942|4更新时间：2025-07-16
- 摘要：This paper proposes a novel method for fast calculating the scattering pattern of large plane arrays.In this method,the induced element patterns of large plane array are constructed from those of a small plane subarray.Then the scattered field of the large plane array is obtained by summing over the induced element pattern of all elements.Furthermore,the method is modified to reduce the computational burden.The expression of the modified method is derived and the large plane array analysis problem is converted into four simplified small plane array problems.In addition,the effects of the mutual coupling and the surrounding array environment are rigorously taken into account.Example arrays of horn antennas are analyzed to assess the proposed method.The calculated results agree well with the ones simulated by HFSS.关键词：plane arrays;scattering;subarray2|1439|3更新时间：2025-07-16
- 摘要：For the stepped frequency high resolution full polarization radar,high resolution full polarization imaging method using spare signal representation is studied,and a novel imaging method based on polarization smoothed l0-norm algorithm is proposed in this paper.A new joint-sparsity is defined by exploiting the scattering characteristics of target in fully polarimetric channels synthetically in the presented algorithm,thus the imaging results combine the merits of fully polarimetric processing technique and sparse optimization algorithm,and can not only provide high resolution range profiles using limited measurements,but also indicate the true polarimetric scattering characteristics of the target,which are beneficial for further applications such as target recognition.Finally,the validity of the proposed approach is demonstrated using both simulated data and real data measured in an anechoic chamber.关键词：sparse signal representation;high-resolution full polarization;sparse imaging;l0-norm2|1293|5更新时间：2025-07-16
- 摘要：The direction deviations of the calibration sources would seriously degrade the calibration precision of the sensor positions.Aiming to this problem,the robust calibration algorithm for estimating the sensor shape against the location deviations is presented under the condition that the prior probability distribution of the direction deviations is available.The robust algorithm is derived based on the signal subspace fitting (SSF) technique and the Bayesian estimation theory frame,and it is numerically implemented via the Newton iteration without optimizing the locations of the calibration sources.Both the theory analysis and simulation experiments validate that the novel algorithm has preferable robustness against the location deviations of the calibration sources and its asymptotic performance can reach the Cramé-Rao bound (CRB) under some moderate conditions.2|1419|3更新时间：2025-07-16
- 摘要：Lattice structure is applied in a wide range of areas due to its excellent finite word length (FWL) properties.The normalized lattice structure is orthogonal,but for an Nth-order digital filter,it needs 5N+1 multipliers.To decrease the computing complexity while keeping the orthogonality unchanged,the scaled elementary lattice and the corresponding lattice structure were derived based on the one-,two-,and three-multiplier lattice,respectively.The simulation result indicates when the scaled one-multiplier lattice is applied,the proposed structure has close performance compared with the normalized lattice structure,but it is more efficient for the real-time signal processing,for it needs only 2N+1 multipliers,much less than that in the normalized lattice structure.关键词：digital filters;lattice structures;signal power ratio;sensitivity measure;finite word length2|1749|2更新时间：2025-07-16
- 摘要：InSAR signal simulator is an important equipment in the hardware-in-loop simulation of distributed SAR,the nonideal channel characteristic of which will affect the evaluation accuracy.The correction of channel amplitude and phase characteristic based on the real-time filtering is studied.A novel correlation and windowing method is used to extract the channel characteristic in the loop data.A method based on the complex Remez algorithm and the genetic algorithm is used to design the complex FIR coefficients.Finally,a FPGA technique is used to implement the complex FIR filter.The channel mismatch peak-peak value of the simulator is corrected from 1 dB/ 10 degree to 0.1 dB/1 degree.The hardware-in-loop simulation validates the proposed real-time correction approach.关键词：InSAR signal simulator;channel amplitude and phase characteristic;real-time correction;hardware-in-loop simulation2|1785|2更新时间：2025-07-16
- 摘要：In this paper the range walk correction in time domain is introduced to revise the range compressing of the traditional frequency scaling algorithm.In the azimuth compressing,a method named azimuth nonlinear chirp scaling is involved to solve the azimuth position dependence of the azimuth modulation rate introduced by the range walk correction.The simulation experiments verify the correct and validity of the proposed algorithm in focusing the echo of high squint spotlight SAR.关键词：synthetic aperture radar;spotlight mode;frequency scaling algorithm;range walk correction2|1386|2更新时间：2025-07-16
- 摘要：Adaptive sum and difference beampattern of array radar encounters some problems,such as signal cancellation,finite sample supports,beam-pattern maintaining and zero-point constraint and so on.In this paper,an adaptive sum and difference beamforming approach based on magnitude and phase response linear constraint is proposed.In this method,magnitude and phase response constraints on several other directions are set and these directions are around that of the assumed signal.This robust beamforming approach effectively overcomes the signal cancellation problem and shows considerable improvement in signal-to-interference-plus-noise ratio (SINR).Through imposing these constraints on both magnitude and phase responses,the sum and difference beamformers are drawing up to the standard static beamformers at the region of the main beam.This approach is robust against signal presence in training data.And through properly setting the magnitude and phase constraints,we can implement azimuth and elevation uncoupling in monopulse angle estimation.Simulation examples demonstrate the effectiveness of the proposed method.关键词：adaptive sum and difference beampattern;magnitude and phase linear constraint;robust beamforming;two-dimensional uncoupling;monopulse angle estimation2|2082|6更新时间：2025-07-16
- 摘要：In allusion to multi-parameter estimation of multi-spectrum spin echo train (SET) signal in the presence of additive white Gaussian noise,a two-dimensional (2-D) parameter estimation method based on eigenvector is proposed.Using SET signal to construct a 2-D data matrix,and according to the different manner to form Hankel block matrix pencil,the eigenvector is resolved by utilizing the shift-invariance structure of the signal subspace,and then,the damping factor and frequency are estimated according to the structure rule of the eigenvector.The complex amplitude of SET is then obtained on the basis of standard least squares.The method has the capability of auto association.Under relatively large signal-to-noise ratio (SNR) and available frequency resolution conditions,it can estimate the parameters effectively,and has an attractive computation complexity.Simulation results show the effectiveness of the proposed algorithm.关键词：nuclear quadrupole resonance (NQR);spin echo train (SET);two-dimensional parameter estimation;eigenvector-based;shift-invariance structure of the signal subspace2|1201|0更新时间：2025-07-16
- 摘要：In this paper,we propose a distributed tree-based algorithm for precise data gathering in wireless sensor networks called EEDAT,which achieves longer network lifetime than existing distributed algorithms.The EEDAT algorithm has two steps.In the first step,a shortest path tree is constructed in a distributed manner.In the second step,EEDAT adjusts the load of nodes in the generated tree to balance energy consumption of different nodes,which effectively extends the lifetime of the network.In the adjustment,both the number of children of a node and its residual energy are considered.Simulation results show that EEDAT achieves longer lifetime than the LMST algorithm.On average,compared with LMST,EEDAT prolongs the lifetime by 20%.关键词：Wireless sensor networks;data gathering;spanning tree2|1621|3更新时间：2025-07-16
- 摘要：IoT(Internet of Things)systems are facing more and more challenges,such as increasing network size,diversities of sensors,complexities of protocols and difficulties of management with expansions of its applications.So,we proposed a novel technique of plus and play which provides functions of service discovery,intelligent configuration and service mapping.Beside,we designed a fuzzy adaptive configuration method,named as EasiFLC.Experimental results show that when application's requirements,topologies of sensing layers or wireless channel conditions change,EasiFLC adjusts network parameters dynamically,thus it ensures quality of services with lowest cost,and achieves good environmental adaptability,strong robustness.关键词：Internet of Things;plus and play;gateway;intelligent configuration;fuzzy control2|2089|0更新时间：2025-07-16
- 摘要：Multi-stage attacks recognize process have similar relationship with solving intelligent planning problems.Intelligent planning is used in multi-stage attacks recognition,in order to achieve the attack scenarios recognition.A multi-stage attack recognition model based on intelligent planning is proposed,and based on this,a multi-stage attack scenario recognition algorithm is realized.Experiments on DARPA datasets shows this algorithm have acceptable accuracy and completeness rate in multi-stage recognition.关键词：multi-stage attack;intelligent planning;attack scenario recognition2|1851|3更新时间：2025-07-16
- 摘要：Sampling control of the trajectory following of delayed multi-agent systems with dynamic leader is studied.Suppose multi-agent system is composed of n agents and one leader with a static weighted interconnection topology graph where leader is a globally reachable node.By applying the Hermit-Biehler theorem,the sampling control of delayed multi-agent systems with dynamic leader is researched,a sufficient and necessary condition is presented for the he trajectory following of delayed multi-agent systems with sampling-data.Finally,the effectiveness of the results is validated by computer simulation.关键词：dynamic leader;communication delay;sampling control;multi-agent systems;trajectory following2|1375|1更新时间：2025-07-16
- 摘要：Complexity characteristics of logistic map,simplified Lorenz system and hyper-chaotic Lorenz system are analyzed based on C0 algorithm.Compared with the Lyapunov spectrum and bifurcation of the systems,the results show that C0 complexity reflects complexity of chaotic systems correctly.Deceasing order on complexity of the systems is logistic map,hyper-chaotic Lorenz system and simplified Lorenz system.Compared the results of spectral entropy(SE)and intensive statistical algorithm(LMC)with that of C0 algorithm,it shows that C0 algorithm can be used to analyze complexity of chaotic systems effectively.Analyses of evolution complexity of time shows that complexity of chaotic systems fluctuates within a certain range which means system has evolution stability,and complexity of sequence y is the biggest anong the sequences of the two continuous chaotic systems.It provides a theoretical and experimental basis for the applications of chaotic systems in the field of information encryption and secure communication.关键词：C0 algorithm;dynamical characteristics;complexity;simplified Lorenz system;hyper-chaotic Lorenz system2|2604|13更新时间：2025-07-16
- 摘要：In this paper,a novel autofocusing algorithm of inversed synthetic aperture radar (ISAR) imaging based on sparse constraint is proposed,which can be applied in sparse aperture ISAR imaging.In the scheme,taking the phase errors as model errors,the proposed approach exploits the sparsity prior of ISAR image to construct the minimum 1-norm image formation.Then numerical method is adopted to realize adaptive phase error estimation while well-focused ISAR image can finally be obtained.Meanwhile,the objective function of ISAR imaging is established based on matrix model,which can be conveniently solved using fast Fourier transform (FFT) and matrix Hardmard multiplication.Due to the utilization of sparsity restriction,the proposed approach can still be capable of performing well even in the case of low signal-to-noise ratio (SNR).The experimental results using both simulated data and measured data confirm the validation of the proposal.关键词：inversed synthetic aperture radar (ISAR);sparse aperture;autofocusing;sparse constraint2|2079|5更新时间：2025-07-16
- 摘要：Considering the voltage mode controlled flyback converter as the example,this paper studies Hopf bifurcation and quasi-periodicity phenomena in isolated switching converters.The discrete map of the system is derived based on total ampere-turns.Using stroboscopic sampling,bifurcation diagram is obtained with the control period as the bifurcation parameter.Hopf bifurcation phenomenon is studied by calculating the eigenvalues of the period-1 orbit as the equilibrium point loses its stability.The correct expression of natural period with the transformer is presented and the relationship between natural period and control period at Hopf bifurcation point is explained.The rotation number is used to distinguish the evolvement of quasi-periodicity and frequency locking phenomena.The embodiments of the Farey principle,devil's staircase and the expression of rotation number of quasi-periodicity are investigated as well.Finally,experimental results show that the theoretical analysis is correct.关键词：total ampere-turns;flyback converter;Hopf bifurcation;quasi-periodicity;frequency locking;Farey principle;devil's staircase;continued fraction2|1687|0更新时间：2025-07-16
- 摘要：There are many kinds of software vulnerability prediction models which are capable of predicting the total number and the time interval of occurrence of vulnerabilities in the software. But none of them can predict the severity of software vulnerabilities. However,in some cases,such as software credibility,we have to consider the total number of software vulnerabilities and time interval as well as the vulnerability severity affecting the trustworthiness of software. Considering the impact of the vulnerability severity,the application and risk control of software is also very important in the traditional software security. Based on the traditional Markov model,we classified the severity of software vulnerabilities occurrence,proposed a new software vulnerability prediction mathematical model. The model can not only predict the total number of software vulnerability and the time interval,but also the total number vulnerabilities of each class as well as the type of the vulnerabilities. Our tests showed that it has better accuracy,and the type of information that other prediction models can not offer.关键词：predicting model of vulnerabilities;Markov chain;prediction with classificaiton;third party prediction of vulnerabilities3|1934|4更新时间：2025-07-16
- 摘要：Long-life electronic products need to be put in stress environment for long durations in order that items with infant mortality or defects are weeded out from the products.However,long stress durations cause aging effects on good items.For some products,failures are defined in terms of performance characteristics degrading some critical values.For reducing durations and aging effects,this paper analyzes the difference between normally and abnormally degraded products,assumes the distribution of product degradation characteristic variable is contaminated distribution model,and presents a degradation screening test design.This design firstly ascertains the model coefficient using identifiable condition of contaminated distribution combined with the analysis of degradation test,and then ascertains screening duration and screening critical value.Lastly,this paper gives an example to illustrate the feasibility of the design.关键词：degradation data;environmental stress screening;contaminated distribution;nonparameter estimation;test design2|1823|1更新时间：2025-07-16
- 摘要：LDA (Latent Dirichlet Allocation) is widely used in text analysis and images processing.However,LDA and most of its modifications are unsupervised learning models,which are not appropriate for classification especially multi-label classification problem.Through the study on the multi-label documents and LDA models,this paper proposes a new Labeled LDA model,namely Shared Background Topics Labeled LDA(SBTL-LDA).In this new model,each label has not only a set of local topics,but also has several background (global) topics.Experienmental results show that SBTL-LDA can decrease the affect of similarities and dependence between different topics and because the label of document is mapped as a combination of local topics and shared topics,so it has a high accuracy when learning from multi-Labeled documents.In addition,this model can be viewed as a semi-supervised clustering model which can utilize the information of labels and outperfom other models.关键词：latent Dirichlet allocation;text analysis;multi-label learning;semi-supervised clustering2|2358|11更新时间：2025-07-16
- 摘要：This paper surveys the state-of-the-art research on query logs analysis.First,the existing corpus of query logs and the information embedded in are summarized and analyzed.Then,important tasks benefiting from query logs are introduced,including web search,information extraction,as well as some closely related topics.Finally,the problems and challenges of current researches are discussed.This paper aims to make a summary,comparison and analysis of the mainstream methods and the latest progress,expecting to be helpful to the future research.关键词：analysis on query logs;mining on query logs;web search;information extraction2|2339|5更新时间：2025-07-16
- 摘要：Equivalent circuit of a millimeter wave limiter is analyzed based on Butterworth (maximally flatness) low pass filter model.Considering the parasitic components of the limiter diodes,the whole limiter physical structure is setup.Diode parasitic parameters,bonding wire inductances,and complete limiter circuit matching networks are analyzed with EM software.A Ka full-band low insertion loss limiter is realized,the measured small-signal insertion loss is lower than 4.3dB in 26~40GHz,the lowest insertion loss is 2.2dB,and the VSWR is better than 1.95:1.At large signal condition with input continuous wave power of 0.5W,the peak leakage power is lower than 10.5dBm.The dimension of the limiter is 20?12?6mm3, and its performance achieves the level of similar foreign products.关键词：millimeter wave;equivalent circuit model;butterworth low pass filter;limiter3|1765|7更新时间：2025-07-16
- 摘要：With the proliferation of high-end mobile devices that feature wireless interfaces,many practical applications are enabled in opportunistic networks which comprise mobile devices.Contrary to the traditional networks,opportunistic networks utilize the mobility of nodes to relay messages based on the store-carry-forward paradigm.We propose an efficient P2P query algorithm based on betweenness centrality forwarding (PQBCF) for opportunistic networking,which adopts the metric of betweenness centrality from social network analysis to estimate the active degree of nodes in the networks.PQBCF leverages nodes with greater betweenness centrality as relays to increase query success rate and reduce query latency.Simulation results demonstrate that PQBCF outperforms most state-of-the-art algorithms and achieves approximate efficiency as epidemic with much less resource consumption.关键词：opportunistic networks;P2P query;betweenness centrality;social networks;mobile devices2|1609|3更新时间：2025-07-16
- 摘要：A multi-scale arc height shape description(MSAH)is proposed for image retrieval.This method uses the multi-scale arc height to measure the bending degree of each contour point.At each scale,an arch height function is generated and is suffered from Fourier transform.The Low frequency coefficients of Fourier transform for arch height functions of each scale are combined to form a feature vector as the shape description.At the shape matching stage,the L1 distance between the two features is used to measure the shape similarity.MSAH can not only capture the global features of the shape,but also reflect the details of the shape,therefor it has a higher retrieval accuracy when applied to image retrieval.MSAH is very compact and has a low computational complexity,so it has higher retrieval efficiency.MSAH is evaluated on the MPEG-7 shape database and plant leaf database,all the experiments show that MSAH has higher retrieval performance over the recent proposed transform domain based methods and shape contexts method.关键词：multi-scale arch height;Fourier transform;shape description;image retrieval2|1747|7更新时间：2025-07-16
- 摘要：To study the charge multiplying characteristic of an electron multiplying charge-coupled device(EMCCD),an ionization rate model is presented based on the impact-ionization theory.Aiming at two TI IMPACTRON EMCCD devices,we develop a multiplication model at low fields using avalanche multiplication integral formula.Compared with the multiplication curves on the datasheets of both devices of TC285SPD and TC253SPD,the calculated data from the model are taken as a reasonable fit to the actual curves.A method is put forward to predict the amounts of signal passing through the multi-stage cascaded electron multiplication register containing a fixed-voltage gate,which is useful to adjust and correct the gain of EMCCD devices.The model is suitable for lower temperature environment,in which electron-multiplication technology can be applied to photon counting strategies.关键词：semiconductor devices;charge-coupled device(CCD);low temperature;electron multiplication;ionization coefficient;mathematic model2|1676|7更新时间：2025-07-16
- 摘要：Ego-motion parameter estimation is one of the key problems in driver assistance and robot navigation,etc.An asynchronous estimation method which is applicable to fish-eye camera is proposed.The method estimates rotation parameters and translation parameters respectively based on feature classification and virtual plane projection.It solves the problem in the previous algorithms that rotation parameters and translation parameters influence each other when estimating at the same time,and improves the estimation accuracy.Firstly,camera motion model is simplified with platform motion characteristics,and background features from different distances and positions are classified according to their roles in motion estimation.The motion laws of features in each class are analyzed and induced.And then according to the laws,the distant background features and general background features are used to estimate the rotation parameters,and ground features are used to estimate the translation parameters.The experimental results show that the proposed method is less influenced by illumination or outliers,and more accurate and robust than some traditional methods.关键词：ego-motion parameter;asynchronous estimation;motion vector;monocular vision;fish-eye camera2|1684|1更新时间：2025-07-16
- 摘要：The main problem of the conventional radar altimeter echo model for big antenna mispointing angle is analyzed,and then an echo model containing the sea surface skewness coefficient is derived.This echo model can be used for retracking the echo wave when the antenna mispointing angle is big.Finally,the model is used to process the data of the HY-2A radar altimeter during the stage of adjusting satellite attitude,and the results are compared with the measurements of the buoys of NDBC(National Data Buoy Center).It shows that the model can give more accurate results.关键词：radar altimeter;echo model;mispointing angle;skewness coefficient;HY-2A;retracking2|1505|2更新时间：2025-07-16
- 摘要：Currently,analog-to-information conversion system (AIC) is mainly achieved by random matrix.However,the hardware implementation of the random matrix is complicated and difficult if not impossible.Inspired by the recent theory of compressive sensing (CS) and integrate-and-fire (IF) sampler,we propose a new sampling system which does not contain any random matrix and encodes in the time domain.The output signal sampled by this system can be accurately restored to the original signal.The sampling frequency of the system can be freely controlled if the signal is sparse and the sampling period is sufficiently long.Theoretically,the sampling frequency can be infinitesimal under those two conditions specified.As a result,the amount of data and the power consumption of the system can be significantly reduced.In addition,it is easy to be implemented in practice and has the advantage of no quantization error and so on.The proposed sampling system should have a great potential in applications in the field of broadband signals such as radar signal detection and biological signal measurement.关键词：compressive sensing;analog-to-information converter;integrate-and-fire circuit;sparse signal2|1433|1更新时间：2025-07-16
- 摘要：This paper mainly studies the extended self-similarity of the fractional Fourier transform (FRFT) spectrum of sea clutter and the application of the multi-scale Hurst exponent in FRFT domain to target detection within sea clutter.Considering that the parameter of the extended self-similar process—the multi-scale Hurst exponent can characterize the details of fractal signals in each scale,this paper studies the extended self-similarity of real sea clutter FRFT spectrum and its influencing factors based on real radar data.Then,the characteristic that the multi-scale Hurst exponent in the optimal FRFT-domain scale is relatively sensitive to the target is utilized for designing CFAR detection method within sea clutter.By the verification of real data,the multi-scale Hurst exponent in FRFT domain performs better in separating target from sea clutter than the mono-Hurst exponent and the multi-scale Hurst exponent in time domain.Additionally,because FRFT can effectively accumulate the energy of accelerating target echoes and promote the signal-to-clutter ratio,the proposed detection method has the potential for weak moving target detection within sea clutter.关键词：Target Detection;sea clutter;FRFT spectrum;fractal;multi-scale hurst exponent2|1461|11更新时间：2025-07-16
- 摘要：A novel microwave rectifier based on Schottky diodes,which applies power divider and diodes array to maintain high rectifying efficiency and large power capacitance,is presented.The proposed structure flexibly reaches different power capacitance requirements with a variation of the branch number of the power divider.The rectifier is compact,simple and high efficient.The microwave rectifying efficiency is higher than 60% when the input microwave power is between 36dBm to 42dBm at 2.45GHz.The highest microwave rectifying efficiency reaches 68% at 41dBm input microwave power.The maximum power capacitance achieves 43dBm.关键词：microwave power transmission (MPT);microwave rectifying;power divider2|2293|3更新时间：2025-07-16
- 摘要：A high voltage BCD(Bipolar-CMOS-DMOS)technology by using self-extracted JTE(Junction Termination Extension)trench isolation based on 0.35μm standard CMOS(Complementary Metal Oxide Semiconductor)process has been developed for LCD(Liquid Crystal Display)backlight application.In this technology,HV(High Voltage)circuit block,including low cost VDNMOS(Vertical Double Diffused N-MOS)and LDPMOS(Laterally Diffused P-MOS)with resurf principle,and LV(Low Voltage)block are integrated together.Advanced deep trench isolation technology which has higher integration than conventional P-type isolation is firstly implemented to protect LV block from HV block and sustain the dv/dt,di/dt effect with self-extracted function.The breakdown voltage is above 150V.Finally,it is shown that the performance of designed IC driver can satisfy the EL(Electroluminescent Lamps)lamp application with frequency at least 400Hz of the switch signal and the power supply is about 100V.For the simplicity of the silicon technology,the cost is saved.关键词：bipolar-CMOS-DMOS(BCD);electroluminescent lamps(EL);self-extracted JTE trench(SEJTET);full-bridge1|2008|0更新时间：2025-07-16
- 摘要：This paper introduces a new waveform encoding technology on azimuth-fast time domain for space borne synthetic aperture radar (SAR),this technology can obtain high resolution wide swath imaging capacity by combining the azimuth multiple beams with multiple phase centers.On the transmitter,intrapulse scanning technolog is utilized to form multiple narrow beams on azimuth in this system,which can reduce the sub-doppler bandwidth,and the elevation beam is widened for wide imaging swath.On the receiver,multiple equivalent phase centers are produced both on azimuth and elevation,the range ambiguity is deducted as the result of multiple sub-waveforms separated by digital beam-forming (DBF) on elevation,and the azimuth doppler ambiguity is deducted by doppler spectral reconstruction method.Finally,the multiple sub-doppler spectra are combined to achieve high azimuth resolution.Moreover,the primary system parameters and performance advantage are analyzed.Simulation results confirm this new system can fulfill high resolution wide swath imaging,also within condensed configuration than other space borne SAR system.关键词：space borne SAR;multiple beams-multiple phase centers;multidimensional waveform encoding;high resolution wide swath imaging3|1497|2更新时间：2025-07-16
- 摘要：For a high reliability,on-line testing is efficient in detecting faults on the early stage.A novel scan cell is proposed based on the conventional scan cell,which can protect the operational status from being changed during test.The test process and the functional operation of sequential circuit go in parallel.With a flexible clock selection mechanism utilized,both non-concurrent test and concurrent test can be operated.Simulation results show that these circuits can be test on-line with moderate hardware redundancy,high stability,and negligible time redundancy.关键词：scan chain;scan cell;on-line testing;test vector;redundancy2|1398|0更新时间：2025-07-16
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