基于FPGA的R-64 FFT处理器的实现

快速傅里叶变换(FFT)处理器是大多数数字信号处理和数字通信系统的关键部件.文章实现了一种4 k(4 096)点改进的R-64(基-64)FFT处理器,相对于其他 R-4的流水线结构,具有占用资源更少、控制更简单等特点.该FFT处理器采用浮点数制流水线结构,能够连续处理输入数据,对R-4处理单元的改进减少了62.5%的复数加法器;该FFT处理器基于FPGA的系统时钟能够达到89 MHz,数据吞吐量为4 096 point/46 μs.     

基于CPLD实现可扩展(I)FFT处理器的设计

提出了基于CPLD(复杂可编程逻辑器件)实现傅立叶变换点数可灵活扩展的高速FFT处理器的结构设计以及各功能模块的算法实现,包括高组合数FFT算法的流水线实现结构、读/写RAM地址规律、补码实现短点数FFT阵列处理结构以及补码实现CORDIC(坐标旋转数字计算机)算法的流水线结构等,输入数据速率为20 MHz时,1024点FFT运算时间约为50 us.     

实时可重配置FFT处理器的ASIC设计

设计一种能够完成4,16,64,256或1 024点复数快速傅里叶变换(FFT)处理器芯片.16,64点运算采用基-4级联流水线结构,256,1 024点采用二维运算结构,数据采用块浮点表示.使用Synopsys公司的综合及布局布线工具在SMIC CMOS 0.18 μm工艺上进行ASIC实现.该处理器芯片在100 MHz时钟频率连续工作时,处理一组1 024点FFT序列需要24.8 μs,每隔10.24 μs输出一组1 024点运算结果.该处理器芯片已应用于某宽带数字接收机中.     

基于FPGA的块浮点FFT的实现

在分析基-2 FFT算法的基础上,提出一种用FPGA实现FFT的方法.用块浮点机制,动态扩大数据范围,在速度和精度间得到折衷;模块化设计,易于实现更多点数的FFT运算.采用Verilog语言编程实现,在Quartus II和Modelsim平台下进行逻辑综合和时序仿真,时序分析结果与Matlab计算结果相比较验证了程序的正确性.     

实序列的FFT计算机程序

离散富里叶变换(DFT)是数字信号处理中一个非常重要而又经常遇到的内容,它很容易在数字计算机上用快速富里叶变换(FFT)方法实现.在一般情况下,不论时间序列是实数或是复数,其频谱都是复值的,因此在用标准计算机程序进行N 点FFT 运算时,需要有2N 个存贮单元.如果时间序列是实序列,就可以利用实序列的某些性质来简化程序.通常有两种方法实现实序列的FFT 运算:一是利用N 点变换同时计算两个N 点实序列的频谱.一是用N 点变换计算一个2N 点实序列的频谱。     

基于FPGA的FFT处理器的研究与设计

提出了一种基于FPGA的64点定点快速傅立叶变换(FFT)的实现方案,并采用EP2C70型号的FPGA实现了处理器.该处理器采用按时间抽取的基 2算法和6级流水线结构,每级将乘法器的旋转因子输入端固定为常数而不是作为变量从ROM中读取,流水寄存中间数据结果.采用Verilog语言在RTL级上进行了编程实现,并进行了逻辑综合、时序仿真和硬件测试.硬件测试结果与Matlab计算结果吻合得较好,证明了方案设计和程序的正确性.该处理器具有运算速度快、精度高等优点,适合于高速信号处理的应用场合.     

超高速FFT处理器的研究

提出了在现场可编程门阵列(FPGA)上实现512点基-8快速傅里叶变换(FFT)算法的设计方案.方案采用了单芯片超高速的FFT处理器结构,满足了实时信号的处理要求.通过采用基-8算法、流水线结构以及32位的浮点数据,提高了FFT的运算速度并减少了FPGA内部的资源占用.本设计方案在100MHz的时钟下,完成了512点基-8 FFT运算需要,满足了高速数字信号处理的要求.     

FPGA实现流水线结构的FFT处理器

针对高速实时信号处理的要求,介绍了用现场可编程逻辑阵列(FPGA)实现的一种流水线结构的FFT处理器方案.该FFT处理器能够对信号进行实时频谱分析,最高工作频率达到75 MHz.通过对采样数据进行加窗处理来减少了频谱泄漏产生的误差.为了提高FFT工作频率和节省FPGA资源,采用了由1 024点复数FFT计算2048点实数FFT的算法.此外还介绍了一种计算复数模值的近似算法.     

基于FPGA的高速FFT处理器的设计与实现

针对高速实时信号处理的要求，提出了4096点快速傅立叶变换（FFT）处理器在现场可编程门阵列（FPGA）中的设计与实现方法。该方法采用了按频率抽取（DIF）基4算法和6级流水线结构，每级均采用FIFO存储器实现延迟功能，和四路转接器一起共同完成序列的码位抽取。为了避免数据溢出，采用块浮点结构来表示数据，节省了器件资源。实验结果表明，该方法在保证运算精度和实现复杂度的同时，提高了处理器的数据时钟频率和处理速度。     

线性调频Z变换在数据处理中的应用

讨论一种基于DSP对数据序列进行频谱分析的运算法则。这种线性调频Z变换（简称CZT）是基于DSP处理器采用FFT变换方法对任意长度数据序列进行DFT变换计算。对于同一数据序列,CZT总的运算时间是FFT变换的2～3倍,运算结果和FFT、DFT转换结果一致。CZT适用任意长度采样序列,而非一定要求基2的长度,由此可使处理系统获得最大采样速率、采样大小和频谱分辨率。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.