最新刊期
卷 40 ， 期 9 ， 2012
- 摘要：An electro-optic terahertz (THz) detector with a newly-designed circuit was investigated.A pair of high-quality PIN photodiodes and a low-noise current-voltage conversion circuit were applied to convert the modulated probe laser to voltage signal.These two voltage signals were subsequently sent to a specially-designed differential amplifier with high common-mode-rejection-rate (CMRR) that largely restrain the noise of terahertz signal and avoid the disturbance of probe laser intensity.Then a band-pass filter was employed to control bandwidth and restrain noise of the detected signal.Finally,the weak THz signal was detected via a main amplifier.Experimental results show that the THz detector has high signal-to-noise-ratio (SNR),teeny distortion and wide bandwidth,which fully satisfy the requirement of terahertz time-domain spectroscopy (THz-TDS).关键词：terahertz (THz);electro-optic detection;signal-to-noise-ratio (SNR);sensitivity;terahertz time-domain spectroscopy (THz-TDS)3|1913|4更新时间：2025-07-16
- 摘要：With the development of HF communication and sounding techniques,study on ionospheric sidescatter is of great importance.Ionospheric sidescatter experimental platform is built,and based on this experimental platform,ionospheric sidescatter sounding experiment is made.In the experiment,the (group)distance-frequency-amplitude three-dimensional sidescatter ionogram and sidescatter doppler spectra of sea and land are obtained.With this experimental platform,the ionospheric sidescatter sounding results can be obtained,which can establish a basis for further study on the characteristics of the ionospheric sidescatter channel and the land/sea clutter.关键词：backscatter;sidescatter;ionospheric sounding;ionogram;Doppler spectrum4|1587|2更新时间：2025-07-16
- 摘要：This paper proposes a quadruple precision floating-point elementary function co-processor based on very large instruction word (VLIW) structure (QPC-Processor),which exploits the parallelism through the explicitly parallel technology of the VLIW structure.Variety of quadruple precision elementary functions is evaluated via the different combination of basic operation in the unified hardware.Finally,we prototype the QPC-Processor units into FPGA chip.The experimental results show our design outperforms the software approach by a factor of more than 6.Moreover,high utilization of hardware resource can be obtained in QFC-Processor.关键词：quadruple precision floating-point arithmetic;very long instruction word (VLIW);elementary function;CORDIC algorithm2|1616|1更新时间：2025-07-16
- 摘要：The space-variant defocus effect introduced by wavefront curvature in polar format algorithm (PFA) imagery limits its maximal focused scene size.Several compensation strategies have been developed in literature to solve this problem,e.g.,subaperture processing,space-variant post processing and widefield polar format algorithm.However,all these approaches are based on the assumption that radar platform is following an expected linear trajectory.They still can’t meet the required precision when imaging from arbitrary radar flight path.In this paper,an improved space-variant post processing method for wavefront curvature compensation is proposed.The method computes wavefront curvature error in original phase history domain,and then transforms it into spatial frequency domain by polar format transformation used in image formation.Using the transformed error,we can accurately compensate wavefront curvature effect by space-variant post filtering.Simulation experiments show that the new algorithm has improved focused scene size when applied to phase history generated by non-ideal radar flight path.关键词：synthetic aperture radar;polar format algorithm;wavefront curvature compensation;arbitrary flight path;rugged terrain2|1667|1更新时间：2025-07-16
- 摘要：Taking advantage of the multidimensional unified and simplicity expression of movement characteristics of geometric algebra,an adaptive template matching method for convergence and divergence structure of multi-dimensional vector fields was proposed.The optimal rotor between the original vector field and the standard template is established based on SVD (Singular Value Decomposition).The data adaptive divergence-convergence template generation method is then constructed based on the structure consistency of rotor rotation,and the classification of geometric structure of the vector field based on the rotor rotation angle is proposed.Finally,the adaptive template matching method is constructed based on the geometric convolution.These methods are verified with the wind field of North America.The results suggest that our method can effectively resolve the structural features of the vector field with different dimensions and can do structure-based classification of vector fields.关键词：vector fields;structure character;template match;Clifford convolution2|1847|1更新时间：2025-07-16
- 摘要：Numerical study on cylindrical corrugated Mimicking Surface Plasmons (MSPs) Terahertz (THz) transmission line with and without gradually changed geometric parameters was carried out by means of the finite element method.The results show that the gradual increased size of corrugates both in depth and width will help the confinement of the electromagnetic energy transmission on the surface of the wire,and the structure also has the function of concentration the propagation wave,which brings forth enhancement of the surface plasmon wave during its transmission along the wire.The obtained results will favor the applications of THz transmission,near-field imaging,spectroscopy and sensing.关键词：terahertz;mimicking surface plasmons;transmission line;gradually changed structure2|1676|2更新时间：2025-07-16
- 摘要：Real time data fusion of airborne active and passive sensors was an important technique achieving targets track and recognition.The spatial time multiple hypothesis model (STMHM) algorithm was brought forward to solve the problem.The data-model was respectively constructed for active and passive sensors according to observed data.Fusion-space of STMHM was built upon the active and passive sensors targets-observed-spaces designed from the data-models.Time initialization method was put forth.Filtering algorithm and judgment rules were discussed.We design an aerial situation data,and then use the algorithm to fuse these data and analyze the validity of the algorithm.关键词：active sensor;passive sensor;data fusion;spatial time multiple hypothesis model2|1336|1更新时间：2025-07-16
- 摘要：A real-time rendering method of realistic snow scene with large scale is presented.Firstly,a snowflake physical model and a snowflake moving model in the snowfall are taken into account.Secondly,the wind velocity is separated into the average velocity and the random velocity,which simplifies the computation of wind field.The random velocity is yielded by Perlin noise and the results are stored in a 3D texture,which effectively alleviates the computing cost of the particle system.Thirdly,the snow accumulation model and snow melt model are presented and simulated.Finally,a particle system based on modern GPU technologies is implemented which improves the performance of rendering.The simulating results show that the method is suitable for large scale snow sceneries rendering.This method is applied to a helicopter simulator successfully.关键词：snow scene simulation;wind field model;particle system;real-time rendering2|1510|5更新时间：2025-07-16
- 摘要：Analysis of range and precision is always an important task for high level synthesis.Although several researches have been dedicated to these two problems,in the case of an infinite impulse response (IIR) filter,conventional approaches either constitute major overestimations or cannot handle arbitrary order feedback circuits.In this paper we focus on these problems and propose one efficient heuristic method for range and precision analysis of such circuits.When the input and error bounds are given,the minimum integer and fractional bit-widths can be allocated to satisfy the error bound,which can obtain smaller circuit area.The experimental results prove that the proposed method has fast convergence and robustness.Because a high order IIR can be decomposed to low order IIRs,the method can efficiently handle IIRs with arbitrary orders.关键词：IIR;range;precision;maximum error;bit-width2|1782|0更新时间：2025-07-16
- 摘要：For the distributed target in spherically invariant random vector clutter,a dual-threshold GLRT detector with constant false alarm rate (CFAR) property is derived.The distributed target,which is modeled as a subspace random signal,may be distributed both in range and in Doppler frequency axes.The cell whose signal-to-clutter ratio is higher is selected by the first threshold.Then the accumulation of energy is implemented in these selected cells,and it makes a final decision according to the second threshold.Assuming that the normalized clutter covariance matrix is known,the dual-threshold GLRT is devised.The probability of false alarm of dual-threshold GLRT is derived and it ensures CFAR property.And then according to a secondary data set to estimate the clutter normalized clutter covariance matrix,the adaptive detector is obtained.The performance assessment conducted by Monte Carlo simulation confirms the effectiveness and robustness of the proposed detector.关键词：distributed target;constant false alarm rate (CFAR);double threshold decision;subspace;generalized likelihood ratio test (GLRT)3|1386|5更新时间：2025-07-16
- 摘要：Existing algorithms for canonical correlation analysis(CCA) of multidimensional data streams are mostly based on approximate techniques,but are not the precise algorithms for updates in essence.In this study,a novel canonical correlation analysis algorithm,called TCCA(Tracking CCA),is proposed for tracking the correlations rapidly and accurately between two multidimensional data streams in the time-varying environments.By introducing the technique of rank two modifications to update the eigen-subspace of the sample covariance matrix in parallel,TCCA can rapidly track the correlations of data streams.Theoretical analysis and experimental results indicate that the TCCA algorithm has better stability,high computational efficiency and accuracy.It could be presented as a basic tool for correlation detection on data streams,feature fusion,dimension reduction and other areas of data streams mining.关键词：multidimensional data streams;canonical correlation analysis;rank two modifications;fast tracking;eigen-subspace2|1699|5更新时间：2025-07-16
- 摘要：Pairings have been widely used in the study of identity-based cryptosystems (IBC).Miller algorithm is the key of computing pairings.We propose an efficient Miller algorithm computing Tate pairing based on the double-base chain.Through the application of norm function and conjugate technique,our refinements reduce the total number of lines and vertical lines in the rational function,and replace the inverse by its conjugate in Miller algorithm.Results show that the efficiency of our algorithm can be improved by more than 10% compared with the previous method.关键词：double-base chains;Miller algorithm;Tate pairing;elliptic curve2|1434|1更新时间：2025-07-16
- 摘要：Transmitting a group of chirp signal with random PRI(Pulse Repetition Interval) and down-sampling echoes after deramp processing,we get the 2-dimensional sparse echoes of the target and process the 2-dimensional sparse echoes with compressed sensing method.We utilize this method to improve the efficiency of the ISAR imaging system and also decrease the data rate of the system.A new motion compensation algorithm is put forward through the analysis on the signal model.The new algorithm includes range alignment and phase compensation procedures.The minimizing the entropy of the average range profile method is implemented in the range alignment procedure,while the eigenvector method is used to accomplish phase correction procedure.The presented results show that this algorithm can realize motion compensation according to the 2-dimensional sparse echoes effectively.关键词：ISAR;2-dimensional compressed sensing;motion compensation;range alignment;phase compensation2|1530|3更新时间：2025-07-16
- 摘要：A new cancellation method processed at the superposition of equivalent phase center (EPC) is proposed to suppress deception jamming against multiple-input multiple-output synthetic aperture radar (MIMO-SAR).MIMO-SAR employs co-located antennas in azimuth direction and transmits multiple linear frequency modulation (LFM) signals with step carrier frequency to form crossed EPC,where the echo pairs have the equal delay and different carrier phase.The deception jamming can be eliminated by cancellation processing at each superposition of EPC.Geometry model of MIMO-SAR with co-located antennas is given.The radar echo with deception jamming is analyzed.The difference between deception jamming signal pair at each superposition of EPC and cancellation procedure are discussed.The simulation experiments are performed to validate the proposed method.关键词：multi-input multi-output synthetic aperture radar (MIMO-SAR);anti-jamming;equivalent phase center (EPC);cancellation processing2|1328|1更新时间：2025-07-16
- 摘要：The approaches combining the prediction and residual compensation can be used to reconstruct the compressed sensing video images recursively.In order to improve the precision of the existing prediction schemes,this paper proposes an image prediction algorithm based on the local autoregressive model.Before that,this paper firstly analyses the similarity of local image patches in consecutive images based on the content similarity of two consecutive images and the non-local similarity of each single image,and then takes this similarity as the correlation prior information to estimate the autoregressive parameters of current image.Compared to the existing related algorithms,the recursive reconstruction algorithm exploiting the proposed prediction scheme can achieve higher video images reconstruction performance.关键词：compressed sensing;video images;recursive reconstruction;local autoregressive model;residual compensation2|1532|4更新时间：2025-07-16
- 摘要：During the bandwidth on demand (BoD) procedure of the broadband satellite multimedia (BSM) system,the BoD performance is very sensitive to the bandwidth allocation period (BAP) and bandwidth allocation latency (BAL) by using periodical burst time plan generation (P-BTPG) method.The BoD model is given and the optimal-burst time plan generation (O-BTPG) method is presented by developing the optimal BAP and BAL.Then the large signaling overhead of O-BTPG is focused.An asynchronous burst time plan generation (A-BTPG) method which can generate the BTP asynchronously according to the bandwidth requirements is proposed.The expression of optimal schedule duration and schedule instant is developed,and the workflow is given.Two different bandwidth allocation algorithms were chosen to evaluate performance of the BTP generation methods.Simulation results show that A-BTPG method can be used widely.It can improve the bandwidth responsive ability of the system while controlling the BTP overhead.关键词：satellite communication;broadband multimedia;bandwidth management;burst time plan2|1444|0更新时间：2025-07-16
- 摘要：In the bistatic ISAR systems,in order to solve the problems of weak scatters detection and identification in strong noise background,the stochastic resonance(SR) was applied to extract the information of weak scatters.On the assumption that the strong scatters could be detected,the signals after de-chirp were disposed through transformation in fast time axis firstly,which made the signals satisfy the condition of adiabatic approximation;then the SR was used to detect the signal frequency that expressed the instantaneous range difference;after that,some processing were implemented to confirm the right positions of weak scatters and to improve the output signal-noise-ratio(SNR).Numerical simulations shows that the SR can improve the SNR largely and enlarge the dynamic bound of radar receiver.关键词：inverse synthetic aperture radar;bistatic radar;stochastic resonance(SR);second sampling2|1801|8更新时间：2025-07-16
- 摘要：The performance of GPS receiver is affected by carrier tracking loop.Because of the vulnerability of carrier tracking in high dynamic and weak signal environments,a method of strapdown inertial navigation system (SINS) aiding GPS tracking loop utilized differential control cogitation is proposed.Phase locked loop (PLL) utilized in traditional carrier tracking is analyzed,and the control mode could be considered as PI (proportion and integration) control.Then the stable of tracking loop with information aiding is verified,and differential control item is introduced to achieve carrier tracking,where the Doppler prediction is calculated by SINS output and clock error.Simulation results indicate that the proposed method could shorten the bandwidth of tracking loop,relieve the contradiction between thermal noise and dynamic stress,and thus further improve the frequency response and tracking errors in carrier tracking loop.关键词：carrier signal tracking;Doppler frequency shift;phase locked loop (PLL);differential control2|1628|0更新时间：2025-07-16
- 摘要：The truth degree of formula is the basic concept in quantitative logic from which other concepts are derived.In the present paper the properties and the computation method of truth degree are investigated more in-depth.Firstly,a form of mean representation of definition of truth degree of formula is given in quantitative logic;secondly,with the help of the form of mean representation,the limit theorem is generalized that is a connection of the theories of truth degrees in n-valued logic system and continuity-valued logic system,and the symmetrical characteristic of truth degree is obtained;thirdly,the computational formulas of truth degrees of the propositions with normal forms is given.关键词：quantitative logic;truth degree;mean representation;limit theorem;symmetry theorem;normal form;calculation formula2|1183|11更新时间：2025-07-16
- 摘要：An automatic registration algorithm between infrared and visible images based on step estimation of affine model parameters is proposed.Firstly,the six degrees of freedom of the affine model are separated into some more easily estimated parameters using matrix orthogonal decomposition method,which are skew,scale ratio,rotation,scaling and translations in x and y directions.Secondly,two objective functions are constructed for step estimation of these parameters based on the orientation consensus constraint and alignment measure between segments,respectively,and parameter values which make objective function approximate the global optimum are obtained using SGA (Stud Genetic Algorithm) algorithm.Finally,the estimated values of the parameters are locally refined using Powell algorithm.The experimental results show that the proposed method can make full use of orientation consensus constraint and location distribution information of segments,and realize automatic registration between infrared and visible images efficiently and precisely on condition that two images to be registered contain abundant corresponding segments and diverse distributions of segment orientations.关键词：image registration;infrared image;model decomposition;parameter estimation2|1636|3更新时间：2025-07-16
- 摘要：We present a general approach to compute the analysis window for a given synthesis window in discrete Gabor transform.An auxiliary window is carefully selected and combined with synthesis window to construct a nonsingular block-circulant matrix.We then use fast discrete Fourier transform to compute the inverse of the block-circulant matrix.Since the inverse of the matrix also has block-circulant characteristic,a parallel lattice structures of block time-recursive are thereafter derived to compute the analysis window by exploiting the block structure of the matrices.Compared with the minimum norm solution,the proposed algorithm decreases more computational cost.Experimental results show that the present method is very effective to get a general analysis window.关键词：Gabor analysis window;block circulant matrix;parallel lattice structures of block time-recursive2|1168|0更新时间：2025-07-16
- 摘要：Conventional studies on characteristics of micro-motion targets with precession in ballistic midcourse usually regard the scattering centers of targets as ideal scattering centers,while the motions of practical scattering centers are equivalent to the precession of targets,based on which the educed conclusions usually are of certain limitations.This paper reveals the differences between motions of the target and its equivalent scattering centers.By considering the non-ideal scattering phenomena of practical scattering centers as well as their shielding effects,a new radar echo model of midcourse targets with precession is established based on non-ideal scattering centers.The influence of precession parameuers upon the time-frequency characteristics is analyzed via a set of simulations,while the correctness of the results is validated by experiments in anechoic chamber.关键词：ballistic midcourse;non-ideal scattering centers;micro-motion2|1462|11更新时间：2025-07-16
- 摘要：Considering the poor storage and query performances of nave counting Bloom filter (NCBF),a data structure called geometric Bloom filter (GBF) is presented.In order to achieve space-efficient storage and fast query,the structure introduces the idea of hash fingerprints,partitions Bloom filter twice and stores elements with buckets.Based on theory of differential equation and probability,analytical expressions of GBF are deduced.The relational expressions between error probability and space complexity are also established.Furthermore,the inner characteristic of GBF taking on geometric distribution is proved.Simulated results indicate that GBF can achieve lower error probability and computational complexity without sacrificing accuracy compared with NCBF.关键词：Bloom filter;geometric Bloom filter;synopsis data structure2|1345|2更新时间：2025-07-16
- 摘要：There are some faults for the current ultrasonic pressure measurement system,such as large volume,high-energy consumption,inconvenience,and it can not measure the pressure of liquid in tubule.A minitype integrative equipment in ultrasonic pressure measurement outside tubule is presented.Low-consumption design of emitting circuit and high-speed data collection-storage circuit were used to decrease the energy consumption of system,and a new kind of clamp was designed to improve the stability of echo signal.Lithium batteries as the power,and denoising with empirical mode decomposition (EMD) were used to improve the quality of ecio signal.At last,the pressure measurement model was established to calculate the pressure of liquid in tubule.The liquid in multiple tubules in different size were measured to test the measurement precision of system,and experimental results show that the equipment shows advantage on small volume,low-energy consumption and convenience.When we measure the pressure of liquid in tubule with diameter 14mm,the maximal measurement error is less than 8%.关键词：ultrasonic wave;pressure measurement;tubule;miniature integrative2|1536|0更新时间：2025-07-16
- 摘要：Cognitive radar can adaptively and intelligently reconfigure its transmission and reception system based on the knowledge about the current environment to improve its performance.This paper reviews the development of cognitive radar first,and then reveals its essential character and framework;after that,the key technologies are presented in detail and research advances are discussed;at last,the prospects of cognitive radar are pointed out.关键词：cognitive radar;background sensing;waveform optimization;adaptive radar;intelligent signal processing3|5164|43更新时间：2025-07-16
- 摘要：The largest Lyapunov exponent is an essential criterion to judge whether the time series is chaos or not.However,the traditional methods are complex and time-consuing,which leads to the limitations in engineering application.An improved algorithm based on space grid method for estimating the largest Lyapunov exponent is presented.Firstly,the whole reconstructed phase space is divided into small spaces;then the points locating in these subspaces which are searched when the reference point exists;finally,the characteristic exponent is calculated.Simulation results show that neighborhoods are searched effectively,and the whole calculated time is reduced greatly.In practically,the algorithm is robust to reconstructed parameters,noise and data length,and it is easy to be programmed as well,which make exponents computed of chaos online possible.关键词：chaos;Lyapunov exponent;space grid method2|2234|6更新时间：2025-07-16
- 摘要：Based on lots of research and analysis on indoor radio signal propagation features and the traditional indoor location algorithms,a new method that uses BP(Back Propagation) neural network to fit the indoor radio signal propagation model is proposed,which avoids inaccurately estimating the parameters A and n in the indoor radio signal propagation model.Distance value proportional to the RSSI(Received Signal Strength Indicator) input through the well-trained BP neural network is obtained,and then Taylor series expansion algorithm is used to determine the coordinates of the blind node.Finally,the simulation and experiment results on the ZigBee platform verify the feasibility and effectiveness of the proposed algorithm.关键词：indoor location;back propagation neural network;received signal strength indicator;ZigBee;Taylor series6|2628|22更新时间：2025-07-16
- 摘要：Conflict evidence combination remains unsettled in information fusion field.Based on analyzing the relationship between paradox and evidence conflict,we proposed an effective conflict measurement parameter and a new DST based on local conflict distribution strategy.Numerous examples show that the proposed rule can settle paradox effectively.关键词：conflict evidence combination;evidence theory paradox;evidence combination rule2|1452|17更新时间：2025-07-16
- 摘要：An improved particle swarm optimization with pre-crossover(PSOPC) was proposed to avoid the premature convergence of particle swarm optimization algorithm.An auxiliary population was introduced in which the particles with low fitness but high diversity after each generation were stored.The pre-crossover between the particle in the swarm and the individual in the extra population was implemented,which helps increase the diversity of the particle swarm so as to improve the global convergence.PSOPC was used to train BP neural network to construct a soft-sensing model of C3 concentration of the fluid catalytic cracker unit(FCCU).The experimental results show that the model based on PSOPC and neural network has good precision and strong generalization.关键词：particle swarm optimization;optimization;fluid catalytic cracker unit;C3 concentration4|1258|1更新时间：2025-07-16
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Optimization and Realization of Digital Temperature Control System for CPT Atomic Frequency Standard
摘要：Coherent population trapping (CPT) atomic frequency standards are small-size and low-power consumption atomic frequency standards emerged in recent years.The frequency stability of a CPT atomic frequency heavily depends on the performance of its temperature control system.This article presents our optimization design scheme of the digital temperature control system.In the system the instrumentation amplifier is used to increase the resolution of the temperature measurement,the wavelet analysis de-noise method is used for signal de-noise process,the pulse width modulation (PWM) square wave is precisely modulated through Δ-Σ algorithm,the output resolution is increased,and the harmonic interference is reduced.The realized temperature control system is a small size low power consumption circuit with good performance.With the improved circuit the frequency stability of the CPT atomic frequency standard is improved.This developed temperature control system specially suits for applications in small-size and low-power consumption CPT atomic frequency standards.关键词：digital temperature control system;wavelet analysis de-noise;Δ-Σ algorithm;pulse width modulation;atomic frequency standard2|1387|0更新时间：2025-07-16 - 摘要：Camera calibration is an indispensable step to get three-dimensional information from images.In this paper constant focal length self-calibration from multiple views is under investigation.Our approach is based on explicit constraints which relate absolute dual quadric to its images.Two constrained polynomial minimization problems with respect to two types of parametrization on absolute dual quadric,whose properties are incorporated into the constraints,are proposed and solved by linear matrix inequality relaxation optimization method,which could avoid the local minimum.The difference with the other self-calibration approaches is that constant focal length is also an optimization variable besides the absolute dual quadric in the objective function.Experiments with simulated data and real images show that our approach works well.关键词：self-calibration;constant focal length;global optimization4|1370|1更新时间：2025-07-16
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The Detection of Traveling Ionospheric Disturbances by High-Frequency Backscatter Sounding Technique
摘要：Traveling ionospheric disturbances (TIDs) are periodic electron density fluctuating structures.It is associated with the movement of gravity waves in the upper atmosphere.On the basis of the previous research of the pundit,the method used to identify the TIDs by the high frequency backscatter sounding data is presented,and the technique to obtain the TIDs character parameters is established.Via analyzing the mutibeam-direction backscatter data,the variation character of group path and skip distance with the time and azimuth is researched.And the TIDs parameters including movement period,direction,wavelength,et cetera are obtained.Finally,the research of ionospheric fluctuating characteristic in large areas is achieved.关键词：traveling ionospheric disturbances;backscatter sounding;ionosphere2|1515|2更新时间：2025-07-16 - 摘要：Because channel estimator proposed by B Steiner for TD-SCDMA system is mainly affected by additive noise,those methods using threshold processing is likely to filter out the paths containing strong information whereas the path with noise is falsely kept.Based on the characteristics that a specific user can receive the training sequences of all the downlink users,a multi-user channel estimation method based on threshold processing was proposed.By comparing the amplitude weighted values with a given value,the method firstly removed some channel estimation windows whose Signal Noise Ratio(SNR) were too small,then averaged the rest of the channel estimation windows,and finally,processed the averaged results with threshold processing method to suppress the channel response contributed by noise.Simulation results show that at the same bit error rate,the average SNR required in the proposed method is 1~4dB lower than that in the direct threshold processing method;When SNR is lower than 5dB,the proposed method has the same performance as the weighted-unit method with high complexity.关键词：TD-SCDMA;B Steiner estimator;channel estimation;average channel estimation values;threshold processing2|1269|0更新时间：2025-07-16
- 摘要：In classic EMD,the envelopes fitted by cubic spline interpolation may often occur overshoots.In this paper,a new envelope fitting method based on the least-length constrained interpolation is proposed.Taking the length of the fitted envelope as the target function,Lagrange optimization method is used to optimize the derivatives of the interpolation nodes.With the optimized derivatives,piecewise Hermite interpolation method is used to fit the more smooth envelopes.The result of experiments proves that the new method can solve the overshoots caused by cubic spline interpolation and the artificial bends caused by piecewise parabola interpolation effectively and let the results of EMD more accurate.This method can overcome mode mixing well,which is one of the major drawbacks of the original EMD.关键词：empirical mode decomposition;envelope fitting;optimization method;mode mixing2|1833|8更新时间：2025-07-16
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