高速多路实时数据采集处理系统设计

介绍了以(PLD)为核心处理芯片的多路数据采集系统的实现方法。该系统通过高速状态机直接将采样数据储存到高速缓冲SRAM阵列中，然后再转存至低速存储器(SDRAM)中，再由CPLD构成的滤波器进行数据处理，整个系统由CPLD和单片微控制器进行联合控制。采用3块TI公司的8位80MSPS的高速单流水线A／D芯片TLV5580采集数据，通过延迟流水采样技术可实现对24路通道，最高采样率为240MHz的模拟信号的采集和处理；采用ALTERA公司的CPLD芯片EPF10K10AFC256-1实现数据处理。通过仿真和调试运行，验证了复杂的数据处理过程被大大简化了，整个系统高速、紧凑，具有良好的抗干扰性。     

基于小波零树结构的遥感影像编码方法

提出了基于小波零树结构的遥感影像保持量测精度的有损压缩的编码方法。研究了在不同滤波器长度下遥感影像经小波分解后各分量图像的统计特性，提出了遥感影像压缩的最佳方案是取四系数的小波分解滤波器．并得出了其他一些有意义的结论。     

无刷直流电机状态观测器的设计

从介绍扩展卡尔曼滤波算法原理人手，建立了以不导通相反电势为基础的无位置传感器无刷直流电机的状态观测模型，估算出电机转子位置和速度，最后对模型进行了仿真并给出了仿真结果。     

Dispersion relations for SH-wave propagation in periodic piezoelectric composite layered structures

Propagation behavior of horizontally polarized shear waves (SH-waves) in a periodic piezoelectric-polymeric layered structure is taken into account. The layered structures are consisted of piezoelectric thin films bonded perfectly with polymeric thin films alternately. The phase velocity equations of SH-waves propagation in the periodic layered piezoelectric structure are obtained for the cases of wave propagation in the direction normal to the interface and along the interface, respectively. Filter effect of this kind of structure and the effects of volume fraction and shear modulus ratio of piezoelectric layer to polymeric layer on the phase velocity are discussed in detail, respectively. One set of piezoelectric thin film--polymeric thin film multilayer system (PZT-5H piezoelectric ceramics--polythene) is chosen to show the numerical simulation, basic properties of SH-waves propagation in this particular structure are revealed.     

VBR流令牌桶流量整形的研究

对于可变比特率(VBR)令牌桶流量整形问题,示出令牌桶等待队列长度与丢包率的关系曲线,推导出在保证截止期条件下如何确定令牌桶参数的关系式.针对活动图像工作组(MPEG)视频流模型进行了仿真,仿真结果与理论结果吻合.     

∑-Δ型24位模数转换器在智能变送器中的应用

小信号处理是现场变送器在信号处理上的一个难点 ,由于现场变送器应用环境比较复杂 ,各种噪声和干扰都非常大 ,介绍了高精度 2 4位模数转换器AD7714在小信号处理方面的应用 ,AD7714与单片机 68HC11的硬件接口 ,模拟滤波和数字滤波 ,小信号采样处理的硬件接线图和软件框图 ,用高级语言编制的采样程序举例以及对小信号处理时绘制印刷线路板方面的注意事项     

Extension of IMC tuning correlations for non-self regulating (integrating) processes

The filter term of a PID with Filter controller reduces the impact of measurement noise on the derivative action of the controller. This impact is quantified by the controller output travel defined as the total movement of the controller output per unit time. Decreasing controller output travel is important to reduce wear in the final control element. Internal Model Control (IMC) tuning correlations are widely published for PI, PID, and PID with Filter controllers for self regulating processes. For non-self regulating (or integrating) processes, IMC tuning correlations are published for PI and PID controllers but not for PID with Filter controllers. The important contribution of this work is that it completes the set of IMC tuning correlations with an extension to the PID with Filter controller for non-self regulating processes. Other published correlations (not based upon the IMC framework) for PID with Filter controllers fix the filter time constant at one-tenth the derivative time regardless of the model of the process. In contrast, the novel IMC correlations presented in this paper calculate a filter time constant based upon the model of the process and the user's choice for the closed-loop time constant. The set point tracking and disturbance rejection performance of the proposed IMC tunings is demonstrated using simulation studies and a bench-scale experimental system. The proposed IMC tunings are shown to perform as well as various PID correlations (with and without a filter term) while requiring considerably less controller action.     

Pulsatile Jet Cleaning of Filter Cloths Contaminated with Yeast Cells

The cleaning of filter cloths is necessary to avoid prolonged system downtime and strong fouling. Reliable cleaning concepts are central to the removal of residues from the complex surface of filter cloths. Particle residues, in particular, play a decisive role in the sufficiency of the cleaning performance. Consequently, enhanced particle‐removal cleaning concepts based on pulsatile jets for filter cloths have been developed. By varying the cleaning parameters, it has been demonstrated that increased pulse numbers and velocities improve the cleaning performance. Furthermore, this promising cleaning concept cleaned more effectively than conventional methods. The reduction in the amount of detergent needed is an ecological and economic advantage of pulsatile cleaning.     

Mitigating adjacent channel interference in vehicular communication systems

In the last few decades, dedicated wireless channels were specifically allocated to enable the development and implementation of vehicular communication systems. The two main protocol stacks, the WAVE standards proposed by the IEEE in the United States and the ETSI ITS-G5 in Europe, reserved 10 MHz wide channels in the 5.9 GHz spectrum band. Despite the exclusive use of these frequencies for vehicular communication purposes, there are still cross channel interference problems that have been widely reported in the literature. In order to mitigate these issues, this paper presents the design of a two-stage FIR low-pass filter, targeting the integration with a digital baseband receiver chain of a custom vehicular communications platform. The filter was tested, evaluated and optimized, with the simulation results proving the effectiveness of the proposed method and the low delay introduced in the overall operation of the receiver chain.     

Several variants of Kalman Filter algorithm for power system harmonic estimation

This paper presents the maiden application of a variant of Kalman Filter algorithm known as Local Ensemble Transform based Kalman Filter (LET-KF) for power system harmonic estimation. The proposed algorithm is applied for estimating the harmonic parameters of a power signal containing harmonics, sub-harmonics, inter-harmonics in presence of white Gaussian noise. These algorithms are applied and tested for both stationary as well as dynamic signals containing harmonics. The LET-KF algorithm reported in this paper is compared with the earlier reported Kalman Filter based algorithms like Kalman Filter (KF) and Ensemble Kalman Filter (EnKF) algorithms for harmonic estimation. The proposed algorithm is found superior than the reported algorithm for its improved efficiency and accuracy in terms of simplicity and computational features, since there are less multiplicative operations, which reduces the rounding errors. It is also less expensive as it reduces the requirement of storing large matrices, such as the Kalman gain matrix used in other KF based methods. Practical validation is carried out with experimentation of the algorithms with the real time data obtained from a large paper industry. Comparison of the results obtained with KF, EnKF and LET-KF algorithms reveals that the proposed LET-KF algorithm is the best in terms of accuracy and computational efficiency for harmonic estimation.