共查询到20条相似文献,搜索用时 62 毫秒
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丝网印刷机是LTCC多层基板制造设备中的关键设备之一,介绍了精密丝网印刷机的主要结构及其工作原理,阐述了该设备的关键技术与创新点,并展望了设备的市场前景. 相似文献
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前言丝网印刷是一门新的实用技术,其应用领域越来越广。印制电路是丝网印刷中要求最高的一种,它要求尺寸精度高,尺寸稳定性好,分辨率高,尤其当印制电路向高精度、高密度发展时,对丝网印刷的要求变得越来越苛刻。在日本,以2.54mm为中心的两焊盘间印刷三根线已经实现,走五根线的技术也在开发之中。丝网印刷包括丝网制版和丝网印刷两部分。印刷高质量的精细制品首先取决于高质量的网版。本文将根据作者1988年12月在日本 相似文献
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本文提出了各类触发器分解成D触发器的分解逻辑表达式,利用它把其它类型触发器的时序电路转换成了D触发器时序电路(简称"归D法")。采用"归D法"编制的时序电路CAA(计算机辅助分析)程序,适用于各类触发器时序电路的分析,这样做既简化了软件编程,又提高了分析效率。 相似文献
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部分响应连续相位调制信号在卫星移动信道中的误比特率性能分析 总被引:1,自引:0,他引:1
该文给出了组合卫星移动信道中采用差分相位检测(DPD)和最大比组合(MRC)的部分响应连续相位调制(PRCPM)信号的误比特率计算公式,并给出了有关数值计算结果。 相似文献
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随着互联网的迅速发展以及IPv4地址空间的逐渐耗尽,IPv6作为新版本的IP协议,对IPv4的最终取代将不可避免地成为必然。IPv6在地址空间、安全性、QoS等方面具有IPv4不可比拟的优势,但是要想在短时间内将互联网和各个企业网络中的所 相似文献
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Reliable speech recognition is one of the challenges of user-friendly computing. An Esprit project has brought speech processing in several languages much closer to commercial reality. The authors describe the Polyglot project in which the system for recognising isolated speech in Polyglot builds on a technology originally developed for Italian, extending it to cope with English, French, German, Spanish and Greek. The method consists of three modules: a preselection stage, a fine phonetic analysis and a linguistic module. For each word, the preselection module conducts a fast search across the known vocabulary and selects 2% of the words as the most probable candidates. Fine phonetic analysis hones the possibilities to the best five. Finally, the linguistic module produces a single 'recognised' word after due consideration of its grammatical category (e.g. whether it's a noun or a verb), and the category of the preceding word. All this work is done on a PC (386 or higher) with a specially designed DSP (digital signal processing) board. The results obtained varied with different languages, depending on the intrinsic difficulty of the language and the amount of development work undertaken. The authors discuss the Spanish achievements in Polyglot 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1976,64(9):1413-1417
A Consulting Engineering Department was organized by the General Electric Company in 1910. It was designed to complement the General Electric Research Laboratory through a focus on creative engineering rather than basic science. The Department was conceived and directed during its early years by C. P. Steinmetz. It continued under the able leadership of a Steinmetz protegé, E. F. W. Alexanderson, until its identity was finally lost during a reorgnization in 1951. The Department produced numerous innovations in communications, electronics and power engineering, including a world radio system that provided the technological basis for a new corporation, the Radio corporation of America, founded in 1919. The history of the Department and the philosophy articulated by Steinmetz and Alexanderson are considered from the perspective of recent studies of the nature of science and technology and their interaction. 相似文献