Computationally Efficient Architecture for Accurate Frequency Estimation with Fourier Interpolation

A simplified DFT-based algorithm and its VLSI implementation for accurate frequency estimation of single-tone complex sinusoid signal are investigated. The proposed algorithm estimates frequency by interpolation using Fourier coefficients. It consists of a coarse search followed by a fine search, and its performance closely achieves the Cramer–Rao low bound (CRLB) even in low SNR region. Moreover, a pipelined triple-mode CORDIC architecture is designed to efficiently support complex multiplication, complex magnitude calculation and real division. The triple-mode CORDIC-based radix-4 architecture is employed for the hardware implementation of the frequency estimator, and is suitable for not only fast Fourier transformation but also accurate frequency estimation. A frequency estimator with 1024-point samples is implemented and verified on FPGA. It works at 215 MHz on a Xilinx XC6VLX240T FPGA device, and uses up 4,161 registers and 6,986 slice LUTs. ASIC synthesis results show that it requires an area of 60K equivalent NAND2 gates with a clock rate of 500 MHz at SMIC 0.18 μm technology. The whole latency of the frequency estimator is 2336 cycles. The proposed architecture provides a good trade off between hardware overhead, estimation performance and computation latency.     

1.74μm压应变InGaAs/InGaAsP量子阱分布反馈激光器

制备了1.74μm脊波导结构压应变InGaAs/InGaAsP量子阱分布反馈激光器.采用低压金属有机化合物气相沉积法生长器件材料,应用应变缓冲层防止In的分凝.未镀膜的腔长为300μm的器件阈值电流为11.5mA,100mA时最大输出功率为14mW,边模抑制比为33.5dB.     

Low Power Computing Paradigms Based on Emerging Non-Volatile Nanodevices

Traditional digital processing approaches are based on semiconductor transistors,which suffer from high power consumption,aggravating with technology node scaling.To solve definitively this problem,a number of emerging non-volatile nanodevices are under intense investigations.Meanwhile,novel computing circuits are invented to dig the full potential of the nanodevices.The combination of non-volatile nanodevices with suitable computing paradigms have many merits compared with the complementary metal-oxide-semiconductor transistor(CMOS)technology based structures,such as zero standby power,ultra-high density,non-volatility,and acceptable access speed.In this paper,we overview and compare the computing paradigms based on the emerging nanodevices towards ultra-low dissipation.     

电视台非线性节目制作网的安全性设计

本文结合天津电视台非线性节目制作网的建设过程,分析了非线性制作网络的主要故障,并针对故障原因,介绍和分析该非线性制作网络一系列高可用性、安全性的设计方案.     

SU-8胶曝光衍射效应的模拟及丙三醇补偿方法

基于SU-8胶的UV-LIGA技术是MEMS中制备高深宽比结构的一种重要方法,但由于衍射效应会使结构的侧壁不再垂直.根据菲涅耳衍射模型,考虑了丙三醇/SU-8界面的反射和折射现象,模拟了丙三醇填充在掩膜版和光刻胶之间时的刻蚀图形.计算结果与已有的实验进行了比较,模型基本可以描述这种光刻过程,可在设计时作为参考.     

基于全景图的虚拟现实技术在数字博物馆中的研究与应用

介绍了虚拟现实技术和全景图的概念及其在数字博物馆中的实现方法及其应用技术,结合实例说明了文物全景图在英特网中真实展示的实现方法,阐述了虚拟现实技术应用于数字博物馆的意义及实用性。     

液体火箭发动机环境因子的小概率估计法

针对液体火箭发动机飞行及地面试车数据的特点,提出了其环境因子的小概率估计法.与现有方法相比,所提出的方法更加适用于小子样复杂系统无失效数据情形下环境因子问题的研究.最后用数值例说明了该方法在实际工程应用中的有效性.     

重复使用运载器陶瓷热防护系统

热防护系统是航天飞行器,特别是重复使用运载器的关键技术之一.该系统要求材料具有隔热效果好、重量轻、结构简单、安装和更换容易、寿命长等特点.本文介绍了重复使用航天飞行器的陶瓷热防护系统的材料组成、性能、制备及构件的安装.     

战车火控系统射击诸元解算工程模型误差的动态评估

分析了当前战车火控系统中射击诸元工程解算模型的缺点,进行了精确解算模型的研究,包括解弹道模型和解命中模型,通过比较在相同输入条件下工程模型和精确模型的解算结果,可实现射击诸元工程模型解算误差的动态仿真评估。     

基于头型分布研究我军头盔分号

基于现有的我国<成年人头面部尺寸>国家标准和我军<男军人三维头面型尺寸>国家军用标准研究的开展,分析了我军男军人头型尺寸的分布状况,并获得了标准头型的三维数字化信息,从而提出参考头模的分档和覆盖比率的算法,作为我军步兵盔和其它兵种军盔盔型的分号、配发的理论依据,以提高其工效学性能和工作性能.