A variable rate multipulse speech coder for CDMA cellular systems

Variable Rate (VR) speech coders are classified into: source-controlled VR coders where the rate is selected depending on the local character of the speech, and network-controlled VR coders where an external control signal selects the coding rate. The first category benefits from the variable rate channels used by Code Division Multiple Access (CDMA) mobile communications. The second category is indispensable for the right behaviour of the CDMA systems under conditions as high traffic levels. The VR speech coder presented in this communication exhibits both types of control. The source control is achieved by means of a Voice Activity Detector (VAD) and a phonetic classifier. The network control acts on the selection procedure of the multipulse excitation sequence to the synthesis filter. This is the main advantage of our VR MultiPulse speech coder because by means of an external signal the bit rate can be changed only every 4 msec, without transitions or distortions. Considering one-way communication, six different operating rates can be externally selected ranging from 4.8 to 9.1 kbps for the active frames; an average bit rate of 380 bps is required for the noise frames.This work has been partly funded by the Spanish Research National Plan under grant no. TIC92-0800-C05-02 and by Northern Telecom.     

超薄带精密轧机辊形调节计算机控制

介绍一种超薄带精密轧机的计算机控制系统改造。超薄带精密轧机用于轧制０．０１ｍｍ～０．５ｍｍ的超薄带材，其辊形调节系统是影响带材板形的关键部分。原系统响应慢，可靠性差，难以满足精轧要求。现对该轧机进行改造，采用计算机，将ＰＣＭ（ＰｕｌｓｅｃｏｄｅＭｏｄｕｌａｔｉｏｎ－脉冲码调制）控制与二次型性能指标最优化控制相结合的控制方法用于轧机的的全面管理与控制，不仅大大提高系统精度与运行可靠性，而且实现调整与控制自动化。目前已投入正常运行。     

Human-centred appraoches to control and information technology: European experiences

In this paper, the concept of Human-Centred Technology will be described with regard to the different dimensions of workplace, groupwork and networks and in terms of the frameworks of both society and the natural environment. These different aspects of Human-Centred Systems will be illustrated by a series of case studies representing several European countries. The report covers a wide range of research fields. The emphasis is on technology: the roles of control and information technology in enterprises today — including issues of applying AI — and the strategies of designing and implementing technology taking into account the specific aspects which characterize human-centred systems.     

铁基气门导管材料性能的控制

介绍了在铁基气门导管的生产过程中,加强关键工序的质量管理,以确保产品材料性能的合格与稳定。     

A globally stable discrete-time controller for current-fed induction motors

In this short paper we present a discrete-time field oriented controller (FOC) for current-fed induction motors which insures global asymptotic speed regulation as well as rotor flux norm tracking. To the best of our knowledge, this is the first time such a result is rigorously established for a controller implemented in discrete-time. To insure global stability a condition on the reference for the rotor flux norm, which is time-varying, is imposed. This condition disappears as the sampling period goes to zero, hence allowing for independent speed regulation and rotor flux norm tracking. One important feature of our scheme is that, compared with the first-difference approximation of the classical indirect FOC, the additional computational burden is negligible. It is also shown that the result can easily be extended to the case of tracking time-varying references in speed or position.     

火箭弹道附近大气参数辨识系统的研究

研究了利用雷达实测数据对沿火箭飞行弹道的大气参数进行辨识和外推落点的方法，进而提出了一个对效力射诸元进行修正的方法。在此基础上，对软件系统进行了设计。最后通过仿真试验，分析了系统的准确性。     

多陀螺自动化测试系统研究

针对动力调谐挠性陀螺大批量生产中存在的性能调试和参数标定工作量大的问题，我们专门研制了一套多陀螺自动化测试系统，该系统主要包括多陀螺真空恒温安装基准体、测控台、计算机程控自动化数据采集和仪器等部分，本文着重介绍该系统的组成原理，设计特点和研制成果。     

面向对象工程数据库管理系统O2S并发事务模型

Ｏ２Ｓ是我们在ＳＵＮ工作站上开发的一面向对象工程数据库管理。本文针对工程应用域事务的嵌套性，长时性，数据库逻辑分区性和涉及数据量大的四个显著特点，阐述了Ｓ２Ｓ的事务管理模型。对工程域事务的管理，数据库的恢复和封锁技术进行了讨论。     

大型空间结构动力学与控制研究的若干问题

考察和研究了国外大型空间结构动力学与控制研究的若干问题，分析了该领域的最新进展与动向。资料表明，随着空间站研制计划的深入与发展，空间结构建模，识别、分析以及结构／控制系统相互作用研究取得了重大进展，某些关切技术取得重大突破，但也还存在一些新的问题。国外解决这些问题的技术民方法可供研究、借鉴。     

第四十届国际尖端材料学会年会与展览简介

介绍国外先进材料技术现状与发展趋势，即强调发展新材料技术，低成本生产技术，质量控制技术，重视先进材料应用，两用技术和军转民。