An 8-bit, 200 MSPS Folding and Interpolating ADC

An 8-bit, 200 MSPS folding and interpolating analog-to-digitalconverter, ADC, has been implemented in a 1.2 µmBiCMOS-process. It achieves 7.5 effective bits with a power dissipationof 575mW. The active area is 4mm². The implementationand measured results are presented. A simple analytical modelfor the interpolation-induced nonlinearity in a folding and interpolatingADC using sinusoidal folding is presented. The bowing of thereference ladder due to interaction with the input stages isanalyzed, and analytical models are derived.     

Three-dimensional finite element analysis to predict the effects of SAW process parameters on temperature distribution and angular distortions in single-pass butt joints with top and bottom reinforcements

Achieving adequate top and bottom reinforcement is important to minimize angular distortions in single-pass submerged arc welded (SAW) butt joints. This is achieved in the present work by using a reusable flux-filled backing strip and proper SAW process parameters without resorting to costly distortion mitigation techniques. The butt joints were made without edge (square butts) preparation. The process was also modeled by using three-dimensional finite element analysis by incorporating the top and bottom reinforcements into the modeling. Filler material deposition was also simulated. Temperature distributions and angular distortions obtained from the modeling closely matched with the experimental values. Thus, the cost effective experimental methodology established in the present work can be utilized for minimizing angular distortions in SAW square butts. The modeling methodology adopted can be used for predicting the angular distortions in SAW square butts with top and bottom reinforcements.     

电弧炉炼钢合金成分控制模型

在电弧炉冶炼过程中,合金成分的控制对产品质量具有重要的作用。通常情况下建立以合金成本最低为目标的线性规划模型,并采用单纯型算法求解。在电弧炉模型的应用过程中,合金元素收得率对模型的精度影响较大,但是合金元素的收得率很难准确获得。通过对电弧炉生产过程中影响合金元素收得率的因素分析,建立了以灰色模型为基础的合金元素收得率估计模型,与线性规划模型构成电弧炉合金成分控制模型,提高了模型的精度。经实践应用表明,该模型可以保证按照各钢种成分要求实现准确、经济地进行电弧炉出钢时合金化操作,使钢水成分达到要求范围,有利于实现电弧炉冶炼中钢水的窄成分控制。     

国外埋弧炉(矿热炉)的技术发展

介绍了世界上最大的矿热炉生产公司德国曼内斯曼-德马格公司的埋弧炉最新技术,以及俄国和南非矿热炉技术的最新发展。     

SF_6气体中大电流过零后弧道的介电恢复特性

本文通过实验测得了SF_6气体中自出电弧在电流过零后弧道热气体的击穿特性,同时还测量了电弧电流,电弧电压及灭弧室内气压的变化,并对结果进行了简单的分析和数学模拟。     

一种融合天地基多源数据的电离层反演方法

数据融合是观测数据稀疏条件下电离层精确反演的重要技术途径.文中提出了一种融合天地基多源数据的电离层反演方法.选择地基GNSS、低轨卫星(Low Earth Orbiting,LEO)掩星、卫星信标及垂测仪等手段为观测系统,国际参考电离层(International Reference Ionosphere,IRI)为背景模型,利用改进的克里格插值及乘法代数重构方法实现多源数据的有效融合.以中国区域为例,观测系统模拟试验的结果表明:文中提出的方法能将各类观测资料有效地融合到背景模式中,反演得到的总电子含量及电子密度误差相比经验模型均有显著降低;在地基GNSS观测的基础上,融入地基垂测与天基掩星可有效提升电子密度的反演精度.相关研究结果可为中国现有电离层观测系统的优化提供科学依据.     

基于导频的OFDM系统信道估计算法的研究

本文针对正交频分复用（OFDM）系统中导频信道估计算法,研究了几种常用的导频信道估计算法和插值算法,通过理论分析和实验仿真,分别对比分析了几种导频信道估计算法和插值算法的性能,为工程应用提供理论和实验依据。     

一种基于合成带宽技术提高SAR分辨率的新方法

近年来,一种多chirp脉冲合成大带宽的技术受到雷达界的关注,该方法可以在降低系统瞬时带宽和采样率的情况下提高距离分辨率.针对子脉冲信号的参数如采样率、带宽和频段间隔等可能各不相同的问题,本文提出了采用SINC捕值进行信号均匀化重建的方法,并通过前处理方式来实现合成带宽技术在SAR中的应用.最后的仿真实验验证了本文方法适应于参数各不相同的多频段子脉冲信号,能有效提高距离分辨率.     

基于改进BP算法的中间视合成方法

本文提出了一种新颖的基于改进BP算法的中间视合成方法。方法中首先改进了BP(Belief Propagation)算法来提高视差估计的正确率,然后在视图插值中设计了新的插值策略,在区域分类的基础上有针对地进行中间视合成。实验结果表明,采用本文提出的中间视合成方法可以获得具有很好视觉效果的虚拟视图。      

2GS/s 6-bit 自校准快闪ADC

A single channel 2-GS/s 6-bit ADC with cascade resistive averaging and self foreground calibration is demonstrated in 0.18-μ m CMOS. The calibration method based on DAC trimming improves the linearity and dynamic performance further. The peak DNL and INL are measured as 0.34 and 0.22 LSB, respectively. The SNDR and SFDR have achieved 36.5 and 45.9 dB, respectively, with 1.22 MHz input signal and 2 GS/s. The proposed ADC, including on-chip track-and-hold amplifiers and clock buffers, consumes 570 mW from a single 1.8 V supply while operating at 2 GS/s.