ITU-T G.334-1988 2.6/9.5mm标准同轴电缆线对上的18 M Hz系统 18 MHz systems on standardized 2.6/9.5 mm coaxial cable pairs

pdf标准 ITU-T G.334-1988 2.6/9.5mm标准同轴电缆线对上的18 M Hz系统 18 MHz systems on standardized 2.6/9.5 mm coaxial cable pairs

12 页 0 下载 0 浏览 0 评论 0 收藏 3.0分
温馨提示:当前标准最多只能预览 10 页,若标准超出了 10 页,请下载原标准以浏览全部内容。
ITU-T G.334-1988 2.6/9.5mm标准同轴电缆线对上的18 M Hz系统 18 MHz systems on standardized 2.6/9.5 mm coaxial cable pairs  第 1 页 ITU-T G.334-1988 2.6/9.5mm标准同轴电缆线对上的18 M Hz系统 18 MHz systems on standardized 2.6/9.5 mm coaxial cable pairs  第 2 页 ITU-T G.334-1988 2.6/9.5mm标准同轴电缆线对上的18 M Hz系统 18 MHz systems on standardized 2.6/9.5 mm coaxial cable pairs  第 3 页 ITU-T G.334-1988 2.6/9.5mm标准同轴电缆线对上的18 M Hz系统 18 MHz systems on standardized 2.6/9.5 mm coaxial cable pairs  第 4 页 ITU-T G.334-1988 2.6/9.5mm标准同轴电缆线对上的18 M Hz系统 18 MHz systems on standardized 2.6/9.5 mm coaxial cable pairs  第 5 页
下载标准到电脑,方便使用
还有 5 页未阅读,继续阅读
本标准由 5zbz2018-09-16 14:35:56上传分享

国外分类,ITU,ITU-T(电信标准分局),itu,5mm,标准,同轴,电缆,同轴电缆,hz,系统,mhz,systems,on,standardized,mm,coaxial,cable,pairs

INTERNATIONAL TELECOMMUNICATION UNION )45 4 ' TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU ).4%2.!4)/.!, !.!,/'5% #!22)%2 3934%-3 ).$)6)$5!, #(!2!#4%2)34)#3 /& ).4%2.!4)/.!, #!22)%2 4%,%0(/.% 3934%-3 /. -%4!,,)# ,).%3  -(Z 3934%-3 /. 34!.$!2$):%$  MM #/!8)!, #!",% 0!)23 )45 4 Recommendation ' (Extract from the "LUE "OOK) NOTES 1 ITU-T Recommendation G.334 was published in Fascicle III.2 of the Blue Book. This file is an extract from the Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, the contents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below). 2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. © ITU 1988, 1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. Recommendation G.334 Fascicle III.2 - Rec. G.334 18 MHz SYSTEMS ON STANDARDIZED 2.6/9.5 mm COAXIAL CABLE PAIRS (Geneva, 1980) Introduction Amplifier design technique has made it possible to provide a usable band of about 18 MHz while still keeping the repeater spacing of about 4.5 km as defined in Recommendation G.332; the CCITT has therefore defined an 18 MHz system which offers a transmitting capacity of 3600 telephone channels in the case of pure telephone application. Alternatively, the system may be used for the transmission of up to two TV channels or one TV signal plus 1800 telephone channels. Another possibility is that the bandwidth above 12 435 kHz could be used for the provision of an 8448 kbit/s digital path. 1 Arrangement of line frequencies for telephony The arrangement of line frequencies most suitable for the network of a particular Administration depends to a high degree on the organization of this network with respect to the interconnection with and through connection to the other systems existing in this network. On the other hand, it is very desirable to limit the number of different frequency plans for the 18 MHz system. The CCITT therefore recommends that in any case one of the following three plans should be applied. However, in international connections between countries which use different modulation procedures (see Recommendation G.211) and in the absence of any special arrangements between the interested Administrations including, if necessary, the Administrations of transit countries, Plan 1 is to be preferred. 1.1 Frequency arrangement of Plan 1 Plan 1 uses the first modulation procedure described in Recommendation G.211. The telephone channels should first be assembled into basic supermastergroups. The four supermastergroups are transmitted to line in accordance with the frequency arrangement of Figure 1/G.334. Note - The arrangement of the supermastergroups No. 1, 2 and 3 is the same as in Plan 1A of the 12-MHz system (Recommendation G.332) and supermastergroup No. 4 corresponds to its arrangement in Plan 1 of the 60-MHz system (Recommendation G.333). 1.2 Frequency arrangement of Plan 2 This Plan uses the second modulation procedure described in Recommendation G.211. The telephone channels should first be assembled into basic (No. 1) 15-supergroup assemblies. Four 15-supergroup assemblies are transmitted to line in accordance with the frequency arrangement shown in Figure 2/G.334. Note - The arrangement of the 15-supergroup assemblies Nos. 1, 2 and 3 is the same as in Plan 2 of the 12 -MHz system (Recommendation G.332). Fascicle III.2 - Rec. G.334 1 FIGURE 1/G.334 Plan 1 frequency arrangement for 18 MHz systems FIGURE 2/G.334 Plan 2 frequency arrangement for 18 MHz systems 1.3 Frequency arrangement of Plan 3 This Plan uses the first modulation procedure described in Recommendation G.211, but adds a further intermediate frequency position. The telephone channels should first be assembled into basic supermastergroups. The four supermastergroups are then translated into the position of the supermastergroups Nos. 6-9 as in Plan 1 of the 60-MHz system (Recommendation G.333). 2 Fascicle III.2 - Rec. G.334 By translating with an additional 40 480 kHz carrier frequency, these supermastergroups are transmitted to line in accordance with the frequency arrangement of Figure 3/G.334. Note 1 - This arrangement is best suited to those networks which need frequent direct through-connections between the 18-MHz and 60-MHz systems. It therefore makes use of a wider frequency band for through-connection than the basic supermastergroup. The arrangement is also suitable for the interconnection of

给标准打分
您好可以输入 255 个字符
本站的中文名字叫什么( 答案:找标准 )
评论列表
  • 暂时还没有评论,期待您的金玉良言