1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 - TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!).4%.!.#% ).4%2.!4)/.!,G0G042!.3-)33)/.G0G03934%-3!.!,/5%G9.5-“%2).G0G0/&G0G04(%G0G0#(!%,3).G0G0!G0G02/50)45G134G0G0RecommendationG0G0- (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation M.320 was pub
2、lished in 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 bel
3、ow).2 In 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, electr
4、onic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle IV.1 - Rec. M.320 1Recommendation M.320Fascicle IV.1 - Rec. M.320NUMBERING OF THE CHANNELS IN A GROUP1 GeneralThe position of a channel within a group is identified by a number starting from
5、1, the numbers of the differentchannels being taken in order of frequency in the basic group frequency band.A channel is said to be erect within a group when the frequencies in the group-frequency band correspondingto the audio-frequencies in the channels ascend in the same relative order as those i
6、n the channels forming the group.Similarly, a channel is said to be inverted within a group when the frequencies in the group-frequency banddescend in the same relative order as the ascending order of the frequencies in the channels.A group, supergroup, etc., is said to be erect when all of its chan
7、nels are erect and is said to be inverted whenall of its channels are inverted.1.1 8 channel groupBasic group B is inverted. The channels will be numbered from 1 to 8 in descending order of frequency withinthe group-frequency range. (See the recommended arrangement in Recommendation G.234 1.)The num
8、bering is as shown in Figure 1/M.320.1.2 12 channel groupBasic group B is inverted. The channels will be numbered from 1 to 12 in descending order of frequencywithin the group-frequency range.The numbering is as shown in Figure 2/M.320.1.3 16 channel groupChannels of a 16 channel group are normally
9、assembled in the basic group B frequency range. The channelsare numbered from 1 to 16 in descending order of frequency within the basic group B frequency band, theodd-numbered channels being erect and the even-numbered channels being inverted. It is therefore not possible in thiscase to speak of an erect or inverted group.The numbering is as shown in Figure 3/M.320.d01-scFIGURE 1/M.320.D012 Fascicle IV.1 - Rec. M.320d02-scFIGURE 2/M.320.D02d03-scFIGURE 3/M.320.D03Reference1 CCITT Recommendation 8-channel terminal equipments, Orange Book, Vol. III-1, Rec. G.234, ITU,Geneva, 1977.
