1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 - TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!).4%.!.#%G0 ).4%2.!4)/.!,G0G042!.3-)33)/.G0G03934%-3!.!,/5%G9.5-“%2).G0G0).G0G0#/!8)!,G0G03934%-3)45G134G0G0RecommendationG0G0- (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation M.380 was published i
2、n Fascicle IV.1 of the Blue Book. This file is an extract fromthe Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below).2 In
3、 this Recommendation, the expression “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic orm
4、echanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle IV.1 - Rec. M.380 1Recommendation M.380Fascicle IV.1 - Rec. M.380NUMBERING IN COAXIAL SYSTEMS1 Numbering of groups, supergroups, etc., and of channels in coaxial systems1.1 Numbering of a supermaster
5、group or of a 15 supergroup assemblyThe supermastergroups and 15 supergroup assemblies of a coaxial system are identified by numbers givingtheir respective position in the frequency spectrum transmitted on the line. The numbering is shown in Figures 1/M.380,2/M.380 and 3/M.380.1.2 Numbering of a mas
6、tergroupThe mastergroups of a coaxial system are identified by numbers giving their respective position in thefrequency spectrum transmitted on the line. The numbering is shown in Figures 1/M.380, 2/M.380, 4/M.380, 8/M.380and 10/M.380.Alternatively, when a mastergroup is regarded as being part of a
7、supermastergroup, the position of themastergroup can be indicated by the number of that supermastergroup followed by the number of mastergroup within thebasic supermastergroup (for example, in Figure 1/M.380, the 5652-6884 kHz mastergroup in a 12 MHz system withsupermastergroup frequency allocation
8、is designated by the two numbers 2 and 8).1.3 Numbering of a supergroupThe supergroups of a coaxial system are identified by numbers giving their respective position in thefrequency spectrum transmitted on the line. The numbering is shown in Figures 2/M.380, 5/M.380, 6/M.380, 7/M.380and 9/M.380.The
9、position of a supergroup that is part of a mastergroup is designated by the number of that mastergroupfollowed by the number of the supergroup within the basic mastergroup (examples: in Figure 1/M.380, the 5652-5892 kHz supergroup in a 12-MHz system with supermastergroup frequency allocation is desi
10、gnated by the threenumbers 2, 8 and 4; in Figure 8/M.380, the 4332-4572 kHz supergroup in a 6-MHz system with mastergroup frequencyallocation is designated by the two numbers 4 and 4).The position of a supergroup that is part of a 15 supergroup assembly is designated by the number of that 15supergro
11、up assembly followed by the number of the supergroup within the basic 15 supergroup assembly (for example,in Figure 3/M.380, the 10 356-10 596 kHz supergroup in a 12-MHz system with frequency allocation by 15 supergroupassemblies is designated by the two numbers 3 and 9).1.4 Numbering of a groupThe
12、position of a group is designated by the number of the supergroup in which it is placed followed by thenumber of the group within that supergroup (examples: in Figure 1/M.380 the 5844-5892 kHz group in a 12-MHzsystem with supermastergroup frequency allocation is designated by the four numbers 2, 8,
13、4 and 1; in Figure 8/M.380,the 4924-4972 kHz group in a 6-MHz system with mastergroup frequency allocation is designated by the three numbers4, 6 and 3).1.5 Numbering of a channelThe position occupied by a channel is designated by the number of the group to which it belongs followed bythe number of
14、the channel within that group (examples: in Figure 1/M.380, the 5884-5888 kHz channel in a 12-MHzsystem with supermastergroup frequency allocation is designated by the five numbers 2, 8, 4, 1 and 2; inFigure 8/M.380, the 4936-4940 kHz channel in a 6-MHz system with mastergroup frequency allocation i
15、s designated bythe four numbers 4, 6, 3 and 9).Note In this system of numbering, the order of the numbers corresponds to a decreasing bandwidth, that is tosay, number of supermastergroup (if any) followed by the numbers of the mastergroup, supergroup, group and channel.2 Standard frequency allocatio
16、ns on 2.6/9.5 mm coaxial pairsThe CCITT has recommended various methods for allocating supermastergroups, mastergroups, supergroupsand 15 supergroup assemblies on 2.6/9.5-mm coaxial pairs. The method for each standard system is given below. Theidentification numbers are shown in each figure to facil
17、itate application of the rules set forth above.2 Fascicle IV.1 - Rec. M.3802.1 12-MHz systems using valves or transistorsThe frequency allocation for 12-MHz systems is in conformity with scheme 1A, 1B or 2 shown inFigures 1/M.380, 2/M.380 and 3/M.380.The CCITT has also recommended the frequency-allo
18、cation scheme in Figure 4/M.380 for the simultaneoustransmission of telephony and television.2.2 4-MHz systemsScheme A of Figure 5/M.380 shows the frequency-allocation scheme used in this case. The 2604-kHz pilot isused only in the 2.6-MHz system described below in 2.3.The 4287-kHz pilot is recommen
19、ded only for 4-MHz systems on 1.2/4.4-mm coaxial pairs.2.3 2.6-MHz systemsThe frequency-allocation scheme for a 2.6-MHz system uses the scheme in Figure 5/M.380 retaining onlysupergroups 1 to 10 inclusive.The pilots are: 60 or 308 kHz and 2604 kHz.3 Standard frequency allocations on 1.2/4.4-mm coaxi
20、al pairsThe CCITT has recommended various methods for allocating supermastergroups, mastergroups, supergroupsand 15 supergroup assemblies on 1.2/4.4-mm coaxial pairs. The method for each standard system is given below. Theidentification numbers are shown in each figure to facilitate application of t
21、he rules set forth in 1 above.3.1 12-MHz systemsThe frequency-allocation schemes are the same as for 2.6/9.5-mm pairs (see Figures 1/M.380, 2/M.380and 3/M.380).3.2 6-MHz systemsThe frequency allocation for 6-MHz systems is in conformity with scheme 1, 2 or 3 shown in Figures 6/M.380,7/M.380 and 8/M.
22、380.3.3 4-MHz systemsThe line-frequency allocation scheme A shown in Figure 5/M.380 is the same as for 2.6/9.5-mm pairs.However, the 4287 kHz pilot must be transmitted continuously if one of the Administrations concerned so requests.Scheme B of Figure 5/M.380 shows the line-frequency allocation sche
23、me used for mastergroups.3.4 1.3-MHz systemsThe line-frequency allocation scheme is in conformity with one of the schemes shown in Figures 9/M.380and 10/M.380.Fascicle IV.1 - Rec. M.380 3d01-scFIGURE 1/M.380.D01d02-scFIGURE 2/M.380.D02 =4 Fascicle IV.1 - Rec. M.380d03-scFIGURE 3/M.380.D03 =d04-scFIGURE 4/M.380.D04 =Fascicle IV.1 - Rec. M.380 5d05-scFIGURE 5/M.380.D01 =d06-scFIGURE 6/M.380.D06 =d07-scFIGURE 7/M.380.D07 =6 Fascicle IV.1 - Rec. M.380d08-scIGURE 8/M.380.D08 =d09-scFIGURE 9/M.380.D09 =d10-scFIGURE 10/M.380.D10 =
