一种计算机可控脉冲宽度和脉冲间隔的矩形波发生器

研制了脉宽、脉间可调的矩形波发生器，综合比较了几种电路的优缺点，设计出了计算机控制的脉冲宽度、脉冲间隔最小调整量为0.25μs，最高频率可达2MHz的矩形波发生器。     

A Computer-Controlled Multichannel Stimulation System for Laboratory Use in Functional Neuromuscular Stimulation

Laboratory instrumentation systems for developing functional neuromuscular stimulation (FNS) orthoses must be flexible in command processing and in multichannel stimulus control and coordination. For research and development of new FNS systems to control the musculoskeletal function of disabled individuals, we have developed a computer-controlled multichannel stimulation system. This system both processes patient generated input commands delivered from a variety of sources, and coordinates the multichannel stimulation to achieve the desired movement. The flexibility provided by this system has proven to be of great value in both upper and lower extremity FNS.     

A Tactile Vision-Substitution System for the Blind: Computer-Controlled Partial Image Sequencing

We have developed a computer-controlled tactile vision-substitution system as part of a study to maximize the use of the skin's ability to process spatial and temporal information. The system receives a 128-column × 64-row image from a commercially available digital camera. An IBM personal computer sections the image into a controllable number of 6 × 24 blocks. The computer then sequentially sends these blocks to the 6 × 24 vibratory fingertip stimulation matrix on an Optacon reading device for the blind. Custom hardware provides the interface between the IBM PC and the Optacon. The image manipulation software is written in Intel 8088 assembly code.     

Computer-Controlled Cycle Ergometer

This communication describes a computer-controlled cycle ergometer that generates any dynamic work rate stimulus between 0 and 350 W. The ergometer system features true "zero" watt pedaling and a response time less than 0.5 s. The work rate stimulus is generated via computer software.     

激光微细加工中微小曝光区域的计算机温度测量系统

在半导体的激光微细加工技术里，微小曝光区域的温度分布是关键的工艺参数，必须得到精确的测量。而为了使温度测量不影响曝光区的温度分布，需采用不接触测量方法。研制了计算机温度测量系统，实现了微小激光曝光区温度的实时不接触测量。系统中，InGaAs／InP光探测器将微小高温区的温度信号转换为光电流．再经信号放大及模／数转换后输入计算机。结合温度定标实验，对测得的温度数据进行插值运算，在实验中可以实时显示出曝光区的温度值。系统的温度分辨率可达到0．2℃，测量区域的最小直径可达到18μm。同时设计了搜索算法，使温度数据采集和精密位移平台的移动相配合，实现了温度分布的测量和最高温度区的准确定位。     

Automatic Focusing of a Computer-Controlled Microscope

An on-line focusing procedure for a computer-controlled microscope employed in the measurement of human chromosome images is discussed. The method is based on an algorithm proposed by Mendelsohn and Mayall. A focusing accuracy of standard deviation less than 1/20th micron in the slide-objective distance has been achieved. Changes of the focus position with time, and for individual chromosomes within a metaphase, have been investigated. The method has proved insensitive to imperfections in the scanner photocathode. The method has also been used to determine the autofocusing accuracy of an analog metaphase-finding apparatus.     

Computer-Controlled Spectral Measurements of Blood Cells

A Zeiss scanning microscope photometer with a monochro-mator was assembled and interfaced with a Digital Equipment Corporation PDP-12 computer to form an automated single-beam microspectrophotometer for making spatial and particularly spectral scans of Romanowsky-stained blood cells. The spectra, covering 400-700 nm, are stored on tape for subsequent data processing. The limitations on the accuracy and precision of the measurements are discussed. Photo-metric precision was limited by ±1% peak-to-peak fluctuations associated with the source and with mechanical instability. However, in strong absorption bands digitization error predominated. These random errors were reduced by time-averaging of multiple sampling points, and by averaging data for several cells. Photometric accuracy was limited by stray light, which produced an apparent transmittance of 0.014 for an 8-?m-square opaque object. Distributional error was found to be 6.6% in a neutrophil nucleus. Spectra were obtained for 24 cells each for nucleus and cytoplasm of neutrophils, basophils, eosinophils, lymphocytes and monocytes, and for erythrocytes. Six blood specimens were used. The biological variability in absorbance produced ±17% coefficient of variation for cytoplasm and erythrocytes and ±7% for nuclei. The spectra are interpreted on the basis of metachromatic and nonmetachromatic thiazine absorption peaks, the eosin absorption peak, and unresolved eosin-thiazine peaks.     

Application of Computer-Controlled Spectrum Surveillance Systems to Crime Countermeasures

A computer-controlled spectrum surveillance system, and application of such a system to crime countermeasures, is described. The system covers the frequency range of 5 kHz to 12 GHz. All functions are controlled via mini-computer, with output directly compatible with batch processing computers.     

GaAs器件工艺中等离子刻蚀及计算机辅助监控技术研究

用Ｎ２气和ＮＦ３反应气体，在较低的刻蚀功率下实现了用薄正性光刻胶ＡＺ１５１８作掩模，均匀、快速刻蚀ＳｉＯ２，ＳｉＯＮ，Ｓｉ３Ｎ４，ＷＮ，Ｗ等材料的等离子刻蚀技术。利用到蚀过程中射频参数的变化和计算机技术，将射频参数的变化在计算机屏幕上实时显示，实现了计算机辅助监控和终点检测技术。     

Computer-Controlled Synthesis of Tomograms by Means of a TV Storage Tube

An improved electronic system for synthesizing tomograms is described. All functions are controlled by a minicomputer. The addition of TV images is performed by a video storate tube. Resolution values of the individual components as well as of the total system are given.     

Stereotaxic Implantation of Electrodes in the Human Brain: A Method for Long-Term Study and Treatment

A stereotaxic method for placement of electrodes in the human brain is described. Radiographic visualization of subcortical targets are discussed and error correction formulas are developed. Electrodes and fixation methods for long-term human implantation are described. Multiple stainless steel or silver bail electrodes have been implanted in 75 patients with schizophrenia, epilepsy, depression, Parkinson's disease, narcolepsy, and intractable pain. The silver ball electrode is more satisfactory for recording and stimulation. Biphasic 0.25-ms duration currents from 2-7 mA have been applied to animals and humans without evidence of structural damage.     

A Series-parallel System

This paper investigates the pdf of time to system failure of a series-parallel system subject to failures and repairs and derives expressions for pdf's of times to system failure in terms of their Laplace Transform.     

一种适于CATV光缆电视的FTTH系统

日本的“CATV2005’年会”于2005年6月15-17日召开，与会人员达8．8万余人，据称是历史上规模最大的一次盛会。“新媒体”杂志社对年会上出现的新潮流归纳了四点：一是CATV台在自办节目中利用电子节目指南（EPG）增加了用户；二是本国制作的内容（节目）的传播率剧增；三是电子购物节目活跃；四是适用于CATV光缆电视的FFTH系统的正式登场。     

一款车载GPS系统解决方案

提出一款车载GPS系统的解决方案     

A Double-Loop Tracking System

A nonlinear analysis which can be used to assess certain statistical characteristics of double-loop tracking systems is presented. It takes into account the mutual coupling effects of the loops in the system. Two approaches are taken to obtain steady-state probability density functions (pdf's) of the system phase errors, φ1and φ2From these pdf's, important system performance statistics, e.g., the phaseerror variances, can be calculated, thus illustrating the application and usefulness of the analysis. The analysis is applied to a satellite transponder as an example.     

一种混沌通信系统

无扩散Lorenz方程是著名的Lorenz混沌模型单一参数简化形式。对一种单一参数无扩散Lorenz方程进行了分析推导,证明了此系统能很好的达到混沌同步,从而能很好地应用于保密通信。仿真结果与理论分析达到了很好的一致。同时,电路仿真也说明此系统同样能够应用到一个实际的电路中,从而具有很好的应用价值。     

浅谈会议电视

从不同的组网技术方面简要讲述会议电视系统的构建方案,介绍会议电视的系统标准.     

A Picture Browsing System

We describe a system for storing pictures in a database and retrieving them from a remote location over a low bit-rate channel. Even with compression techniques, it takes a long time to transmit a picture, making search for a picture of desired attributes time-consuming. Our system improves the human interaction with the picture database by constructing an auxiliary text database containing a list of attributes of each picture, a hierarchical encoder-decoder, and a light pen to select the areas of picture buildup. Picture searching (or browsing) takes place in two stages: in the first stage, knowing the required picture attributes, a user selects a subset of pictures by matching attributes to the text database; in the second stage, these selected pictures are displayed hierarchically so that a low resolution picture is reproduced first and made sharper gradually. A light pen allows the user to give priority to upgrade selected areas or reject a picture. Our techniques of hierarchical coding are simple to implement. Informal tests indicate that it is much easier to browse through a picture database using this system and that the time to retrieve a picture of given attributes decreases considerably compared to sequential picture presentation.     

A Waveguide Quadruplexer System

Practical design considerations are presented for a relatively simple four-channel wave guide branching system. The most important electrical characteristic of this system is an extremely low pass-band reflection coefficient (better than 1.5 per cent in 30-Mc band) which has only very small variations with the environmental conditions.     

A New MIMO-OFDM System

1　Introduction　Recently ,Multiple InputMultiple Output (MI MO)systemhasbecomearesearchfocusinwirelesscommunication[1～5] .Thesystemcapacitycansig nificantlyimprovedifmultipletransmitandreceiveantennasareusedtoformMIMOchannels.Accord ingtoRef.[1 ],comparedwithaSingle InputSin gle Output (SISO)systemwithflatRayleighfadingornarrowchannels ,aMIMOsystemcanimprovethecapacitybyafactoroftheminimumnumberoftransmitandreceiveantennas.　InOFDM (OrthogonalFrequencyDivisionMulti plexing) ,th…