共查询到20条相似文献,搜索用时 93 毫秒
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1PAL-D制NICAM数字声技术简介PAL-D制NICAM数字声技术,简称“丽音”技术,适合于中国现行的PAL-D制电视系统附加数字立体声或双声道广播接收,使中国的电视伴音由模拟单声道广播跨入了数字立体声广播。附加NICAM数字声电视,采用了NICAM-728技术,NICAM是Near InstantaneousCompanded Audio Multi-plex的缩写,含义为准瞬时压扩音频复用,传输速率为728kb/s。NICAM是由英国BBC公司研究成功的,用于地面和卫星广播,已有PAL-… 相似文献
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本文着重分析了NTSC、PAL-M、PAL-N三制式彩电的特点以及和PAL-D/K制的异同点,并给出三制式彩电的实现方法。 相似文献
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讨论了PAL-D制NICAM数字立体声伴音选择5.85MHz载频的原因;提出用户应如何接收PALD NICAM节目的方案,并对如何进行PAL-D NICAM节目转播加以说明。 相似文献
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宁波GSM系统LAC状况 目前宁波GSM系统共有LAC区22个,每个BSC分配一个LAC(除市区BSC23,BSC24外),这样,某些BSC的Location-Update占OK-ACC-PROC的比例(后称LU-RATE)相当高,如余姚BSC8,其LU-RATE高达79.42%,其SDCCH负荷相当重,且已导致SDCCH拥塞,具体每个BSC的LU次数,LU-RATEPAGE-REQUESTS/PAGE-RESPONSE,PAGES-PER-SECOND,SD-CONGESTION-RATE,… 相似文献
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本刊1998年第5期《NICAM728在我国地面电视广播中的传输与应用》一文,曾介绍了我国地面电视广播丽音标准《PALD电视广播附加双声道数字声技术规范》(GY/T129—1997),及其在北京电视台的试播情况。一年以来,北京电视台除用立体声成功... 相似文献
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本文介绍了欧洲采用的由PAL制向高清晰度电视过渡制式-PALplus。PALplus不仅与PAL制兼容,而且采用16:9宽屏幕图象格式,清除了PAL制的亮色串扰,提高了图象的清晰度。文中以PALplus编码器为例,详述其主要技术及基本原理。 相似文献
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近年来,随着集成电路技术的飞速发展,出现了一种用户可定义其逻辑功能的器件-可编逻辑器件,简称PLD器件。其发展经历了PROM、FPAL、PAL、GAL,直至现在广泛应用的大规模PLD器件EPLD、CPLD及目前最流行的可编程逻辑门阵列FPGA。本文详细介绍了美国受特梅尔公司的EPLD-ATV2500H/L的内部结构和功能特点。读者只要再学会TANGO-PLD、ABEL、CUPL等语言中的一种,便能 相似文献
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NICAM 728数字声电视广播系统是由BBC研究开发的,它可用于I、B、G、H等制式的电视系统,除传送电视图像和模拟调频单声信号外,还可传送两路高质量数字编码声音信号。目前,已有不少国家和地区采用了NICAM 728系统,一些国家也正在研究并考虑NICAM 728的应用。本文详细介绍了NICAM 728基带编码方案,调制、传输参数,以及系统的总体轮廊。 相似文献
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比较了PAL-I与PAL-D两种丽音制式的特点,并对兼收两种两音的系统进行了分析,提出了一种较合理的解决办法。 相似文献
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本文比较详细地分析了将NICAM技术运用在我国地面电视通道中的必要性和可行性,对数字载波的频率及频谱成形滤波器的特性参数的选择提出了建议。 相似文献
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本文首先介绍了电视双伴音/立体声广播的几种常用方式,然后着重分析丽音(NICAM)双伴音/立体声广播系统的基本原理,并给出其接收系统的集成电路。 相似文献
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Jean-Yves Tigli Stéphane Lavirotte Ga?tan Rey Vincent Hourdin Nicolas Ferry Christophe Vergoni Michel Riveill 《电信纪事》2012,67(7-8):313-327
Ubiquitous computing applications or widespread robots interactions execute in unforeseen environments and need to adapt to changeful available services, user needs, and variations of the environment. Context-awareness ability addresses such a need, enabling, through adaptation rules, applications to react to the perceived dynamic variations. Responses to adaptation have to be quick enough to maximize the time during which the application is coherent with its environment. Adaptation rules, associating variations of the environment to application reactions, are usually established at design time. However, in unforeseen and partially anticipated environments, we claim that adaptation rules have to be dynamically extensible to match previously unexpected variations. Our approach enables rule composition and ensures a deterministic result. We propose to use parameter adaptation to quickly respond to environmental variations and dynamic compositional adaptation to provide extensibility to the parameter adaptation. To foster even lower response times, we internalize context-awareness processing and decision into the application. 相似文献
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In the Paper, we proposed a threshold mult- proxy multi-signature with share verification.In the scheme,a subset of original signers allows a designated group to proxy signers to sign on behalf of the original group, A message m has to be signed of proxy signers who can represent the proxy group. Then, the proxy signature is sent to the verifier group.A subset of verifiers in the verifier group can also represent the group to authenticate the proxy signature.In othe words,some threshold values will be given to indicate the number of persons to represent a group to authorize the signing capability or to sign a messagye or to verify the proxy signature. 相似文献
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Technical communicators need to be prepared for the challenges of international communication. This tutorial focuses on the need for technical communication faculty to prepare students to be skilled intercultural communicators and to play a role on the translation team. The tutorial begins with a discussion of the importance of writing for translation in the international workplace and then presents specific assignments designed to instruct students in intercultural communication and give them experience writing for translation. In addition to introducing students to the cultural issues that impact the creation of documentation for international audiences, these assignments also serve to reinforce core skills recognized as vital to professional success in the field of technical communication. Taken together, these assignments can be used as the basis for a course in international technical communication. An appendix to the tutorial includes numerous resources available to faculty who want either to develop a course in international technical communication or to include some of the assignments in existing technical communication courses. 相似文献