基于CB的串行口和接口板端口程序应用

串行口及接口板端口是计算机通信的主要途径 ,也是目前计算机工程测控中通用的基本方法。C Builder (简称CB)编程语言以其功能完备、开发效率高的特点而成为目前流行的程序开发工具 ,介绍了利用CB语言编写串行口和端口通信的程序的方法 ,并对具体的各方法编写了相应的示例。     

串行及并行A/D转换器在高速数据采集中的采样差别性分析

串行和并行接口模式是A/D转换器诸多分类中的一种,但却是应用中器件选择的一个重要指标.在同样的转换分辨率及转换速度的前提下,不同的接口方式不但影响了电路结构,更重要的是将在高速数据采集的过程中对采样周期产生较大影响.本文通过12位串行ADC ADS7822和并行ADC ADS774与AT89C51的接口电路,给出二者采样时间的差异性.     

Scheduling Algorithms for Packet-Oriented MAC Protocols in Wireless Multimedia Systems

Future generation wireless multimediacommunications will require efficient Medium AccessControl (MAC) protocols able to guarantee suitable Qualityof Service (QoS) levels for different traffic classes whileachieving a high utilization of radio resources. This paperproposes a new scheduling technique to be adopted at the MAClevel in wireless access systems, named Dynamic Scheduling-Time DivisionDuplexing (DS-TDD), that efficiently managesvideo, voice, Web and background traffics. A theoretical approachis proposed in this paper to evaluate the DS-TDD performance withvoice and Web traffics. Simulation results have permitted tohighlight the following promising characteristics of the DS-TDDscheme: (i) a high capacity of real-time traffics isattained with a QoS insensitive to Web and background trafficloads; (ii) a high throughput can be guaranteed whilepreserving the QoS levels of the different traffic classes;(iii) heavier downlink traffic loads do not modify the QoSof uplink traffics. Finally, extensive comparisons with differentscheduling schemes proposed in the literature have permitted tohighlight the better performanceof DS-TDD.     

Serial deployment of attention during visual search.

This study examined whether objects are attended in serial or in parallel during a demanding visual search task. A component of the event-related potential waveform, the N2pc wave, was used as a continuous measure of the allocation of attention to possible targets in the search arrays. Experiment 1 demonstrated that the relative allocation of attention shifts rapidly, favoring one item and then another. In Experiment 2, a paradigm was used that made it possible to track the absolute allocation of attention to individual items. This experiment showed that attention was allocated to one object for 100-150 ms before attention began to be allocated to the next object. These findings support models of attention that posit serial processing in demanding visual search tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

硬件握手双向选通型串行通信共享器的设计

本文介绍了ＩＢＭ－ＰＣ系列计算机通过ＲＳ－２３２Ｃ串行口与多个单片微机组成的分布式系统中一种可双向选通串行通信共享器的设计方法。给出通信共享器的设计电路；并对电路工作原理进行了详细剖析。     

通用串行总线(USB)数据传输模型

USB作为一种数据传输接口，了解它的通信传输机制是正确利用USB利用数据传输的基础，分层次结构对USB数据传输模型加以分析，可以使读者建立起USB体系结构、通信模型和总线事务的框架和概念，并最终对USB传输工作流程有一个清晰的认识。     

基于TS101型DSP链路口的多通道高精度数据采集电路设计

介绍一种基于数字信号处理器(DSP)TS101链路口的多通道高精度数据采集电路的设计方法,详细阐述利用多个ADS8361型A/D转换器进行数据采集,并经TS101链路口传输数据的FP-GA和DSP设计实现,讨论如何提高A/D转换精度的问题.     

Mobility Influences on the Capacity of Wireless Cellular Networks

Capacity has always been a major concern in wireless networks. This letter studies the impact of mobility on the overall system capacity in wireless cellular networks. In this letter, we present a simple system model which we developed to capture the inherent relationships among system capacity, new call blocking probability, handoff dropping probability, call terminating probability, and bandwidth utilization rate. We investigate the complex relationship between mobility and capacity‐related parameters. Through simulation, we demonstrate that mobility has a significant impact on capacity and is reversely proportional to the bandwidth reserved for handoff traffic.     

回转窑窑体变形的一种实时监测与报警系统

针对回转窑在运行过程中窑体变形的情况开发了一种监测与报警系统。完成了系统的前向通道设计、单片机与PC机的串行通讯设计和报警显示。     

利用手机模块实现无线公话的方法研究

本文论述了无线公话技术的实现原理，详细介绍了利用MCS8051系列单片机控制手机模块实现无线公话的方法，并给出了该类设备硬件各模块的功能描述以及关键部分软件的实现方法。