Sinh-Domain linear transformation filters

A new systematic method for designing Sinh-Domain linear transformation (LT) filters is introduced in this article. For this purpose, a substitution scheme containing the Sinh-Domain LT equivalent of each passive prototype has been introduced. The proposed equivalents have been realised by employing appropriate Sinh-Domain building blocks with low-voltage operation capability. As an example, a third-order Sinh-Domain elliptic LT filter has been designed and its performance has been evaluated through simulation results. In addition, a detailed comparison with the corresponding Sinh-Domain and log-domain counterparts has been performed and the obtained results have been further discussed.     

High speed multiplier using Nikhilam Sutra algorithm of Vedic mathematics

This article presents the design of a new high-speed multiplier architecture using Nikhilam Sutra of Vedic mathematics. The proposed multiplier architecture finds out the compliment of the large operand from its nearest base to perform the multiplication. The multiplication of two large operands is reduced to the multiplication of their compliments and addition. It is more efficient when the magnitudes of both operands are more than half of their maximum values. The carry save adder in the multiplier architecture increases the speed of addition of partial products. The multiplier circuit is synthesised and simulated using Xilinx ISE 10.1 software and implemented on Spartan 2 FPGA device XC2S30-5pq208. The output parameters such as propagation delay and device utilisation are calculated from synthesis results. The performance evaluation results in terms of speed and device utilisation are compared with earlier multiplier architecture. The proposed design has speed improvements compared to multiplier architecture presented in the literature.     

Implementation of a high speed frequency synthesizer employing a dual input phase accumulator

We present a new PLL based frequency synthesizer, in which we have replaced the conventional phase frequency detector and the dividers (programmable counters) with a sequential dual input phase accumulator (DIPA), consisting of a digital circuit employing adders, registers and a ladder. The main feature of the DIPA is that the two input frequencies are not required to be normalized (divided down) to the step frequency of the synthesizer. Instead, the two different high frequencies, that is the reference and the output frequency of the synthesizer, are applied directly. The DIPA samples and normalizes their phases at very high rates, calculates their phase difference, producing an output that consists of a dc component proportional to the phase difference and harmonics of the two input high frequencies. These harmonics are high frequencies and can easily be rejected by a wide bandwidth filter of the loop, without affecting the high convergence speed of the loop. Moreover, these harmonics do not generate spurs near the output frequency. The resolution of the DIPA based synthesizer depends only on the length of the digital word of the DIPA, and its convergence speed depends on the lower of the two input frequencies. The output of the DIPA is a linear function of the phase difference of the two input frequencies and its dynamic range exceeds the limit of ±2π that governs the conventional phase detectors. Thus, the proposed frequency synthesizer based on the DIPA has low phase noise, no spurs nearby the output frequency, high resolution and fast convergence rate. Additionally, the output frequency can be digitally modulated under the control of the closed loop, either by phase or frequency modulation.     

话题发现与追踪技术研究

话题发现与追踪以新闻流为处理对象,采用基于事件的信息组织方式进行研究,一直是自然语言处理领域里的热点。该研究借鉴大量相关研究尤其是信息检索中的经典模型和方法,取得了很大成功。首先介绍了话题发现与追踪的主要研究内容、评价方法以及发展历史;然后对其多个研究内容提出一个统一研究框架,并对该框架中的关键技术进行了详细分析;最后指出该领域中的关键问题及难点,并对未来研究做出展望。     

Sigma-Point直接式卡尔曼滤波惯性组合导航算法

基于西格玛点采样加权的方法,以姿态、速度和位置等9个导航参数为状态向量,以卫星导航系统的速度和位置组成6维观测向量,构建直接式卡尔曼滤波器,融惯性导航系统求解和状态估计的过程为一体,直接描述系统导航参数动态过程.仿真结果验证了惯性组合导航Sigma-Point直接式滤波方法的有效性,表明该非线性直接式滤波方法可提高惯性组合导航系统的导航精度和对飞机、导弹等载体非线性机动过程的适应性.     

An integrated magnetotransistor sensor

The initial voltage offset between the collectors in integrated circuits, including an npn-type dual-collector lateral bipolar magnetotransistor, formed in a well, and polysilicon resistors, is investigated experimentally. The choice of the switching circuit of the magnetotransistor determines the mode of operation and its effect on the offset. The initial offset between the voltages on the collectors is less than 1 mV, which enables the relative value of the useful signal in a weak magnetic field to be increased. Translated from Izmeritel’naya Tekhnika, No. 4, pp. 50–54, April, 2009.     

基于滤波残差的组合导航系统故障检测研究

论文研究了两种用于组合导航系统中的故障检测方法,首先介绍了传统的残差χ2检验法,随后给出了一种基于最大残差样本协方差阵特征值的故障检测算法.通过计算机仿真比较了两种算法在组合系统中的应用,仿真结果显示,基于特征值的故障检验算法对故障较敏感,系统组合精度略高,一定程度上优于传统残差χ2算法.最后,文章讨论了组合导航系统中两种故障检测算法的优缺点.     

动漫类课程艺术素养与技术能力培养途径探析

动漫类岗位需要很强的艺术素养和技能,才能对设计作品有较好的理解和体现。本文对动漫类课程中培养学生的艺术素养与技术能力的途径进行探讨,并对艺术素养与技术能力的综合素质训练及其体现方式进行分析。