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1.
李应凤 《旭光技术》1998,(1):1-3,40
本文主要论述了英国EEV,美国Varian‘sEimacDivision和WestinghouseElectricCorp。以及法国Thomson四家公司在NAB97展示的数字HDTV发射管最新呷极管、MSDC速调管,SiC固态器件,IOT和双端四极管Diacrode的主要技术性能,同时也介绍了上述五种HDTV发射管在数字HDTV发射机中的应用实便。  相似文献   

2.
本文主要论述了英国EEV、美国Varian和法国ThomsonTubes Electronigues三家公司推出的数字HDTV发射管IOT以及TomsonTubes Electronigues新近推向市场的HDTV发射管TH563四极管和双端四极管TH680目前所达到的技术水平,特别着重介绍了上述三种数字HDTV发射管的整机应用情况,同时也展望了IOT,尤其是TH563和TH680的美好应用前景。  相似文献   

3.
本文主要论述了英国EEV,美国Varian和法国ThomsonTubesElectroniques三家公司推出的数字HDTV发射管IOT(InductiveOutputTube)以及ThomsonTubesElectroniques新近推向市场的HDTV发射管TH563四极管和双端四极管(Diacrode—Double-endedtetrode)TH680所达到的技术水平;特别着重介绍了上述三种数字HDTV发射管的整机应用情况,同时也展望了IOT,尤其是TH563和TH680的美好应用前景。  相似文献   

4.
ANovelVoiceCoderAt4800BPS(HSEV)WangXiaofengANDZhaoEryuan(DepartmentofTelecomrnunicationEngineering,BeijingUniversityofPosts&T...  相似文献   

5.
PECVDSiN及其在GaAsMESFET中的应用第Ⅱ部分:PECVDSiN的性质及其对GaAs器件性能的影响罗海云(电子部第13研究所,石家庄,050051)PECVDSiNandItsApplicationinGaAsMESFETPartⅡ:Pr...  相似文献   

6.
本文叙述了Varian,EEV和Thomson于90年代初开发成功的UHF-TV发射管IOT及其应用情况,并着重介绍了Thomson电子管公司1994年最新推出的TU680Diacrode的优良信号传输特性及在未来数字电视方面的美好应用前景。  相似文献   

7.
CMOSIC中浮置栅缺陷的电气模型:I_(DDQ)测试的意义=ElectricalmodelofthefloatinggatedefectinCMOSIC's:implicationsonI_(DDQ)testing[刊,英]/ChampecV.H....  相似文献   

8.
高清晰度电视接收机软件平台——中间件   总被引:2,自引:0,他引:2  
目前,数字高清晰度电视(HDTV)接收机软件平台———中间件(Middleware)尚无统一的定义和标准。美国“大联盟”ATSC系统提出数字电视应用软件环境(DASE)标准;欧洲DVB系统提出多媒体家用平台(MHP)标准。美国SUN公司正在积极推广其JAVA平台进入电视、机顶盒、有线电视领域,并提出基于JAVA2MicroEdition(消费电子)的JAVATVAPI标准。中国高清晰度电视总体组(HDTVTEEG)亦着手研究开发具有中国特色的HDTV中间件,并以此为基础提出中国的中间件标准的建议。本文定义了数字…  相似文献   

9.
元器件卡片     
元器件卡片HARRIS专·递HV400为单只MOSFET驱动器,可提供极大的峰值驱动电流。它用于驱动大功率或并联的MOJSFET。特性:应用:●输出Source4值申流:6A●开关电源●输出Sink峰值电流:30A●DC/DC变换器●工作频率:300...  相似文献   

10.
金如莲 《电声技术》1999,(11):16-18
杜比AC-3是一种高效率、高质量、多功能的感知型数字音频编码技术。在1992年它就为影院提供多声道的数字音频,在1994年应用于二声道的DBS(DirectBroadcastSatellite)。在消费电子业中它已被广泛用于为盒式或碟式家用视音频设备提供多路数字环绕声音频信号。除用于激光视盘机外,它还被用于HDTV的数字环绕声系统,目前的DVD(DigitalVideoDisc)格式中也用了AC-3音频编码系统,其他如DVC(DigitalVideoCassette)和DAB(DigitalAu…  相似文献   

11.
Radio transmission signals are distorted by multipath propagation and signal level fading in the channel. In the case of digital transmission systems, the distortion of signals causes a degradation of bit error performance. It is an especially severe problem with digital outside-broadcasting-link (OBL) which has to transmit, for example, digital HDTV signals at more than about 45 Mbps. The OFDM modulation scheme can mitigate the adverse effects of multipath fading. An experimental OFDM modem has been developed to enable stable transmission of digital HDTV sources in an OBL. The experimental modem distributes transmitting digital data to 688 carriers in a bandwidth of about 13.5 MHz using the 16DAPSK for each OFDM carrier. A combination of 8DPSK and 2DASK is adopted as the 16DAPSK and another combination of 8DPSK and coherent 2ASK instead of 2DASK is also considered. Indoor transmission experiments confirmed that the 16DAPSK-OFDM is feasible for transmitting high bit rate signals, even under severe propagation conditions  相似文献   

12.
DigiCipher, an all-digital HDTV (high-definition television) system, with transmission over a single 6 MHz VHF or UHF channel, is described. It provides full HDTV performance with virtually no visible transmission impairments due to noise, multipath, and interference. It offers high picture quality, while the complexity of the decoder is low. Furthermore, low transmitting power can be used, making it ideal for simulcast HDTV transmission using unused or prohibited channels. DigiCipher can also be used for cable and satellite transmission of HDTV. There is no satellite receive dish size penalty (compared to FM-NTSC) in the satellite delivery of DigiCipher HDTV. To achieve the full HDTV performance in a single 6 MHz bandwidth, a highly efficient unique compression algorithm based on DCT (discrete cosine transform) transform coding is used. Through the extensive use of computer simulation, the compression algorithm has been refined and optimized. Computer simulation results show excellent video quality for a variety of HDTV material. For error-free transmission of the digital data, power error correction coding combined with adaptive equalization is used. At a carrier-to-noise ratio of above 19 dB, essentially error-free reception can be achieved  相似文献   

13.
Tannas  L.E.  Jr. 《Spectrum, IEEE》1989,26(10):31-33
The status of high-definition television (HDTV) displays for industry and the home in Japan is discussed. Key requirements for HDTV displays are examined. Improvements in projection cathode-ray tubes (CRTs), presently the sole display candidate for home HDTV displays in Japan, are described  相似文献   

14.
High definition television (HDTV) services will play the most important role in the digital television systems for the future. HDTV is already broadcast daily in Japan and advanced television (ATV) standards will soon be established in the US. The hardware systems for two HDTV systems, the 1125/60 and 1250/50 systems, have already been developed. Their outlines are described in the paper. Signal processing of HDTV is mainly carried out by digital methods on both the studio and receiver sides. The principles of processing are the same as for conventional television but the higher clock frequency and larger quantity of information require more sophisticated hardware. Digital signal processing methods are the key technology in HDTV broadcasting systems regardless of whether modulation is analog or digital. Some broadcasting systems are already practical use while others, are experimental. The author discusses these systems. The aim of the article is to present a global scope of the HDTV technology  相似文献   

15.
地面数字HDTV的频率规划和信道编码   总被引:2,自引:0,他引:2  
李光球  姚庆栋 《电子学报》1996,24(7):99-103
本文研究地面数字HDTV的频率规划,提出HDTV服务面积的一种近似计算方法,阐述了HDTV两种传输方案中必须解决的关键技术,提出了HDTV应用的级连码设计原则,探讨HDTV的系统结构,对发展我国数字HDTV提出参考意见。  相似文献   

16.
The characteristics of digital high-definition television (HDTV) and its advantages over analog and hybrid systems are described. The issues to be addressed in using digital transmission in the terrestrial broadcast environment are examined. Four proposed digital HDTV systems are discussed, and their similarities and differences are highlighted. Key techniques are the use of complex compression coding and motion compensation algorithms  相似文献   

17.
本文描述在CCIR活动中对HDTV统一标准的争论和趋势。有关ETV,D2-MAC及数字电视地面广播系统的CCIR建议书,以及美国全数字HDTV的发展也作了介绍。  相似文献   

18.
The roles that digital high-definition television (HDTV) compression techniques play in HDTV applications, such as digital HDTV terrestrial broadcasting, are discussed. Images can be encoded intraframe and/or interframe, depending on the requirement of compression rate and the picture quality. Using source coding, redundancy in the spatial and temporal domains can be greatly reduced while preserving the level of image quality required for the given application  相似文献   

19.
The digital modulation methods used by the DigiCipher, DSC-HDTV, ADTV, and ATVA-P digital high-definition television (HDTV) systems are discussed. Three of the systems use a quadrature amplitude modulation method and the fourth uses a vestigial sideband modulation method. The channel equalization and spectrum sharing of the digital HDTV systems is discussed  相似文献   

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