可变2n点流水线FFT处理器的设计与实现

设计一种可以连续计算N点复数序列傅里叶变换(FFT)的流水线结构处理器,其序列长度N(为2的幂)可变.流水线结构由乒乓存储器将基本运算模块级联而成,对输入数据的顺序以及流水运算的级数加以控制便可计算不同长度序列FFT.给出了由序列长度控制输入数据倒序、旋转因子寻址以及数据输出的实现方法.数据采用块浮点表示,提高了运算精度.用硬件描述语言VHDL在寄存器传输级(RTL级)进行描述,并在单片FPGA上实现.该芯片可工作在80 MHz,连续计算时,处理长度为1 024点的序列仅需12.8 μs.     

基-4FFT处理器的优化设计与应用

快速傅里叶变换(fast Fourier transform, FFT)因其高效而广泛应用于信号处理系统。文章通过分析按时间抽取的基-4FFT算法,针对1 024点设计了一款5级流水线型FFT处理器。在处理器结构中每级内采用蝶形运算单元的分时复用方法降低了硬件资源消耗;在5级连接结构设计中采用流水线技术提高算法处理速度。该处理器采用现场可编程逻辑门阵列(field programmable gate array, FPGA)进行验证,结果表明,在50 MHz的条件下,11.9μs即可完成1 024点运算,通过光电容积脉搏波检测应用验证了其正确性。     

基于分级存储并行运算的FFT处理器设计

研究了一种基于分级存储并行运算的改进快速傅里叶变换(FFT)处理器算法,通过减少对RAM存储器的读写次数降低功耗,采用并行运算方法减少数据处理时间.基于该算法以及改进的基-4蝶形单元设计了一款4096点FFT处理器.该处理器采用SMIC 0.18μm CMOS工艺设计实现,芯片核面积为9mm2,在slow工艺角条件下,版图后仿真最高时钟频率为192.3MHz,功耗为422mW@100MHz,最小处理时间为67.92μs.     

一种应用于DC-OFDM系统的FFT处理器设计

设计了一种应用于双载波正交频分复用(DC-OFDM)无线通信系统的高速、低功耗快速傅里叶变换(FFT)处理器.为降低传统并行架构带来的硬件实现开销,提出了一种新型的结合FFT分解的多路并行架构,有效减少了实现所需的乘法器和加法器数目,在提高处理器数据吞吐率的同时,进行了芯片面积的优化.另外,采用提出的处理单元实现不同的基运算,并对基-2、基-22、基-23、基-24不同架构下的定点FFT运算所需的硬件开销进行定量分析,以选择最优的基结构.最后,介绍了旋转因子乘法器的设计.设计实现的128点FFT处理器采用SMIC 0.13μm CMOS工艺,芯片面积为1.44 mm2,最大数据吞吐率达到1GS/s,在典型工作频率500MS/s下的功耗为39.5mW.与现有其他128点FFT处理器相比,减小了面积,节约了功耗.     

快速傅里叶变换(FFT)的ASIC实现及现场可编辑门阵列(FPGA)验证

通过对FFT(fast fourier transformation),即快速傅里叶变换的一般算法的研究对比,确定合理可行的基2方法处理1024点FFT。在ASIC(application specific integrated circuit)专用集成电路上实现FFT硬件模块,并将该模块在FPGA(field programmable gate array)上进行原型验证。采用级联结构设计FFT模块,在尽量减小资源消耗的同时,提高FFT的运算速度。设计采用两组四个深度为256的双口RAM,乒乓结构处理,完成整个运算仅用了1 320个周期。最后用Xilinx公司的Vertex7-XC7VX690T芯片做FPGA原型验证,在时钟频率为50 MHz时,完成1 024点FFT仅用了26.2μs。     

基于ASIC的128点FFT处理器的设计

所研究的芯片是128点定点FFT处理器,该处理器主要应用于超宽带无线通信系统.采用一种适合于128点快速傅里叶变换(FFT)的混合基-22/2的按频率抽取算法,并在此基础上设计一种并行运算与流水线结构相结合的硬件系统.详细描述了系统状态机的设计,最终实现了一个满足时序和设计工艺要求,达到了以下指标:工作频率66 MHz,芯片面积3.54 mm2,功耗为71.6 mW的高性能的FFT的IP处理器核.     

一种高性能FFT蝶形运算单元的设计

基于TSMC 0.18 μm CMOS工艺标准单元库,设计了一种高性能快速傅立叶变换蝶形运算单元.蝶形运算是快速傅立叶变换的核心,单元采用时间抽取的快速傅立叶变换基2算法、并行全流水结构,对IEEE 754单精度浮点数构成的复数进行处理,并可在同一个快速傅立叶变换处理器中并行扩展使用.逻辑综合与版图综合后的报告显示单元的核面积为1.96 mm2.仿真结果表明,单元能够稳定运行在200 MHz时钟下,输出数据误差小,使用一个该单元的快速傅立叶变换处理器完成1 024点数据运算需时27.6 μs,其速度、精度及面积完全达到了设计指标.     

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FPGA的8K点FFT的设计与实现

采用4K点复数FFT实现8K实数点FFT;数据存储单元采用双口乒乓RAM结构;采用级联结构流水线的设计方式,基4蝶形结构完成前6级的运算,双基2蝶形结构完成最后一级运算;使用块浮点溢出检测.实验结果表明,在时钟周期为8.74ns的正常状态下,采用FFT处理器实现8K实数点FFT仅需要35.799μs,达到了高速运算的目的.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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