共查询到20条相似文献,搜索用时 62 毫秒
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当RS-485用于多主通信的总线系统时,多个主机同时发送数据,将会导致数据冲突。为了避免冲突发生,介绍了一种RS-485电路,用简单硬件实现了总线状态的检测,大大降低了数据冲突概率。另外,为了避免总线上的干扰信号影响系统设备,通常需要实现总线与设备内部电路隔离,为此,文中提出了一种新的RS-485电路隔离方案。 相似文献
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基于PCA82C250与MCU间的直连通信网络设计 总被引:1,自引:0,他引:1
在分析了RS-485总线与CAN总线的异同点后,以PCA82C250型接口电路为例提出了用CAN总线通信物理层接口电路来替代RS-485总线接口电路与单片机直接连接进行通信网络设计,从而可形成一个高性能、低价格且数据通信安全、可靠的分布式测控系统. 相似文献
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RS-485低功耗收发器MAX485E 总被引:1,自引:0,他引:1
<正> 单片机串行口的协议信号为RS-232信号,可以利用RS-232串行通信协议直接进行串行通信。但RS-232协议支持的传输距离近,不超过50m。RS-485串行通信协议支持的传输距离远,达1200m,且抗干扰能力强,数据传输速率高,所以,将单片机串行口的RS-232协议信号转换为RS-485协议信号,便可实现单片机的远距离通信。利用MAX485E芯片,可以将单片机串行口的RS-232协议信号转换为RS-485信号,进行远距离通信。 相似文献
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本文简要地介绍了一种基于RS-485总线的税控收款机联网方案,通过一个RS-232/RS-485串口转换器,实现PC机与多台税控收款机之间长距离相互通讯.重点研究了基于RS-485总线的终端设备联网系统的组建、接口电路的优化设计、RS-485串行通信协议的设计和实现. 相似文献
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介绍了一种多台开关电源装置与计算机通信的实现方案,并采用了RS-232c和RS-485双串行通信总线标准接口,实现了计算机可以实时采样和设置电源输出电压、输出电流和各个开关量的状态。 相似文献
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微机与单片机之间除了采用有线通信方式外(如RS-232、RS-485等),还可以采用无线通信方式,如红外线通信方式就是其中的一种。采用红外线通信方式的优点是:省去了有线方式的信号线的直接连接,使用简单,移动方便。微机与单片机无直接连接,属完全隔离状态,两者间不会因电平的不同而 相似文献
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The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde. 相似文献
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解决IP网QoS问题是目前通信领域的研究热点之一.虽然研究已经取得了一定的进展,但人们对于IP 网QoS本身的含义及相关的问题还有着不同的理解.本文将从IP网QoS的定义入手讨论相关的一些问题以及解决IP网QoS问题所做的各种努力. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1968,56(6):1024-1032
Assuming that visual responses are due to the action of particles on the membrane of the visual cells, the stochastic variability of the response should be a function of the number of particles producing it. Quantitative predictions can be made with the aid of a model proposed in previous articles. It is found that responses produced in visual cells of Limulus by absorption of a single photon have the stochastic properties which would be expected if the response to one photon were brought about by 25 particles. It is concluded from this that the processes leading to visual responses produce multiplication of particles. The effects of temperature and of metabolic poisons suggest that these processes are of chemical nature. 相似文献
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By means of exact conformal mapping method we have defined character of dependence of squares amounts of angular part of film
element on angled part dimension. We propose relations, approximating obtained dependence. Calculation results and experimental
researches of large-scale models are represented. 相似文献
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A. M. Emel’yanov 《Semiconductors》2010,44(9):1134-1139
A method for analyzing the luminescence spectra of semiconductors is suggested. The method is based on differentiation of
the spectra. The potentialities of the method are demonstrated for luminescence in the region of the fundamental absorption
edge of Si and SiGe alloy single crystals. The method is superior in accuracy to previously known luminescence methods of
determining the band gap of indirect-gap semiconductors and practically insensitive to different conditions of outputting
radiation from the sample. 相似文献
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“计算机组成原理”设计性实践教学模式研究 总被引:1,自引:0,他引:1
本文阐述了"计算机组成原理"设计性实验教学的重要性,对设计性实验教学的目的和基本特征进行了归纳,对"计算机组成原理"设计性实验教学的现状进行了调查,对存在的问题进行了较深入的分析;在此基础上.对组成原理设计性实验的教学模式进行了研究,对设计性实验的体系进行了初步设计,并对"计算机组成原理"设计性实验的实施方法进行了探讨. 相似文献