1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T G.992.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 2(10/2003) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Access networks Splitterless asymmetric digital subscriber line (AD
2、SL) transceivers Amendment 2: New Appendix IV Example overlapped PSD masks for use in a TCM-ISDN crosstalk environment ITU-T Recommendation G.992.2 (1999) Amendment 2ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CI
3、RCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE L
4、INKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TESTING EQUIPMENTS G.500G.599 TRANSMISSION MEDIA CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM
5、 G.900G.999 General G.900G.909 Parameters for optical fibre cable systems G.910G.919 Digital sections at hierarchical bit rates based on a bit rate of 2048 kbit/s G.920G.929 Digital line transmission systems on cable at non-hierarchical bit rates G.930G.939 Digital line systems provided by FDM trans
6、mission bearers G.940G.949 Digital line systems G.950G.959 Digital section and digital transmission systems for customer access to ISDN G.960G.969 Optical fibre submarine cable systems G.970G.979 Optical line systems for local and access networks G.980G.989 Access networks G.990G.999 QUALITY OF SERV
7、ICE AND PERFORMANCE - GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DIGITAL TERMINAL EQUIPMENTS G.7000G.7999 DIGITAL NETWORKS G.8000G.8999 General aspects G.8000G.8099 Design objectives for digital networks G.8100G.8199 Quality and availability targets
8、 G.8200G.8299 Network capabilities and functions G.8300G.8399 SDH network characteristics G.8400G.8499 Management of transport network G.8500G.8599 SDH radio and satellite systems integration G.8600G.8699 Optical transport networks G.8700G.8799 For further details, please refer to the list of ITU-T
9、Recommendations. ITU-T Rec. G.992.2 (1999)/Amd.2 (10/2003) i ITU-T Recommendation G.992.2 Splitterless asymmetric digital subscriber line (ADSL) transceivers Amendment 2 New Appendix IV Example overlapped PSD masks for use in a TCM-ISDN crosstalk environment Summary This amendment contains Appendix
10、IV, titled “Example overlapped PSD masks for use in a TCM-ISDN crosstalk environment“ to ITU-T Rec. G.992.2, giving an example of overlapped PSD masks for use in a TCM-ISDN crosstalk environment. Source Amendment 2 to ITU-T Recommendation G.992.2 (1999) was agreed by ITU-T Study Group 15 (2001-2004)
11、 on 31 October 2003. ii ITU-T Rec. G.992.2 (1999)/Amd.2 (10/2003) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is respo
12、nsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the I
13、TU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborati
14、ve basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain man
15、datory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. Th
16、e use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU take
17、s no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property,
18、protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2004 All rights reserved. No part of this publication may be r
19、eproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.992.2 (1999)/Amd.2 (10/2003) 1 ITU-T Recommendation G.992.2 Splitterless asymmetric digital subscriber line (ADSL) transceivers Amendment 2 New Appendix IV Example overlapped PSD masks for use in a TCM-ISDN
20、 crosstalk environment This appendix defines example-shaped overlapped downstream PSD masks for use in a TCM-ISDN crosstalk environment. These masks may be used with Annex C modes of operation that use overlapped PSDs. IV.1 Example downstream PSD masks for use with Profiles 5 and 6 In this clause, t
21、wo example downstream PSD masks are described. They may be used for downstream dual bitmap modes with overlapped spectrum. In general, using overlapped spectrum downstream may result in NEXT to the upstream channel. To meet spectrum compatibility requirements, the frequency components overlapping th
22、e upstream channel are shaped to reduce the crosstalk. The first example is a spectrally shaped mask used during the NEXT phase of the TTR clock. The second PSD mask has an alternative spectral shaping and is designed for use during the FEXT phase of the TTR clock. IV.1.1 Downstream shaped overlappe
23、d PSD mask for use during NEXT periods The shaped overlapped spectral mask for use during NEXT periods of the TTR clock is defined in Table IV.1 and shown plotted in Figure IV.1. Spectral shaping is provided in the frequency band overlapping the ADSL upstream channel. Adherence to this mask will res
24、ult in spectral compatibility with other systems deployed in an access network in a TCM-ISDN crosstalk environment. Note that the definitions given in Table IV.1 and Figure IV.1 are those of a PSD mask. The corresponding PSD template is 3.5 dB below the mask at all frequencies. 2 ITU-T Rec. G.992.2
25、(1999)/Amd.2 (10/2003) Table IV.1/G.992.2 Tabulation of a shaped overlapped downstream PSD mask for use during NEXT periods of the TTR clock Frequency f (kHz) PSD (dBm/Hz) Peak values 0 f 4 97.5, with +15 dBrn power in 0-4 kHz window 4 f 32 94.5 32 f 109 94.5 + 20.65 log2(f /32) 109 f 138 58 + 58 lo
26、g2(f /109) 138 f 200 38.3 + 3.36 log2(f /138) 200 f 552 36.5 552 f 956 36.5 36 log2(f /552) 956 f 1800 65 1800 f 2290 65 72 log2(f /1800) 2290 f 3093 90 3093 f 4545 90, peak with max power in the f, f + 1 MHz window of (36.5 36 log2(f /1104) + 60) dBm 4545 f 11040 90 peak, with max power in the f, f
27、 + 1 MHz window of 50 dBm G.992.2_FIV.1NEXT PSD Mask1101010313012011010090807060504030Frequency (kHz)PSD(dBm/Hz)104Figure IV.1/G.992.2 A shaped overlapped downstream PSD mask for use during NEXT periods of the TTR clock ITU-T Rec. G.992.2 (1999)/Amd.2 (10/2003) 3 IV.1.2 Downstream shaped overlapped
28、PSD mask for use during FEXT periods The shaped overlapped spectral mask for use during FEXT periods of the TTR clock is defined in Table IV.2 and shown plotted in Figure IV.2. Spectral shaping is provided in the frequency band overlapping the ADSL upstream channel. Adherence to this mask will resul
29、t in spectral compatibility with other systems deployed in an access network in a TCM-ISDN crosstalk environment. Note that the definitions given in Table IV.2 and Figure IV.2 are those of a PSD mask. The corresponding PSD template is 3.5 dB below the mask at all frequencies. Table IV.2/G.992.2 Tabu
30、lation of a shaped overlapped downstream PSD mask for use during FEXT periods of the TTR clock Frequency f (kHz) PSD (dBm/Hz) Peak values 0 f 4 97.5, with +15 dBrn power in 0-4 kHz window 4 f 4.8 94.5 4.8 f 50 94.5 + 11.0 log2(f/4.8) 50 f 126 57.5 + 15.7 log2(f/50) 126 f 552 36.5 552 f 956 36.5 36 l
31、og2(f/552) 956 f 1800 65 1800 f 2290 65 72 log2(f/1800) 2290 f 3093 90 3093 f 4545 90 peak, with max power in the f, f + 1 MHz window of (36.5 36 log2(f/1104) + 60) dBm 4545 f 11040 90 peak, with max power in the f, f + 1 MHz window of 50 dBm 4 ITU-T Rec. G.992.2 (1999)/Amd.2 (10/2003) G.992.2_FIV.2
32、1101010313012011010090807060504030Frequency (kHz)PSD(dBm/Hz)104FEXT PSD MaskFigure IV.2/G.992.2 A shaped overlapped downstream PSD mask for use during FEXT periods of the TTR clock IV.2 Example downstream PSD mask for use with Profile 3 An example shaped overlapped spectral mask for use with Profile
33、 3 is defined in Table IV.3 and shown in Figure IV.3. Spectral shaping is provided in the frequency band overlapping the ADSL upstream channel. Adherence to this mask will result in spectral compatibility with other systems deployed in an access network in a TCM-ISDN crosstalk environment. Note that
34、 the definitions given in Table IV.3 and Figure IV.3 are those of a PSD mask. The corresponding PSD template is 3.5 dB below the mask at all frequencies. ITU-T Rec. G.992.2 (1999)/Amd.2 (10/2003) 5 Table IV.3/G.992.2 Tabulation of a shaped downstream PSD mask for Profile 3 Frequency f (kHz) PSD (dBm
35、/Hz) Peak values 0 f 4 97.5, with +15 dBrn power in 0-4 kHz window 4 f 5 92.5 + 18.64 log2(f/4) 5 f 5.25 86.5 5.25 f 16 86.5 + 15.25 log2(f/5.25) 16 f 32 62 + 25.5 log2(f/16) 32 f 552 36.5 552 f 956 36.5 36 log2(f/552) 956 f 1800 65 1800 f 2290 65 72 log2(f/1800) 2290 f 3093 90 3093 f 4545 90 peak,
36、with max power in the f, f + 1 MHz window of (36.5 36 log2(f/1104) + 60) dBm 4545 f 11040 90 peak, with max power in the f, f + 1 MHz window of 50 dBm G.992.2_FIV.3Figure IV.3/G.992.2 A shaped downstream PSD mask for Profile 3 Printed in Switzerland Geneva, 2004 SERIES OF ITU-T RECOMMENDATIONS Serie
37、s A Organization of the work of ITU-T Series B Means of expression: definitions, symbols, classification Series C General telecommunication statistics Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone
38、telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Prot
39、ection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Series N Maintenance: international sou
40、nd programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Seri
41、es T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communications Series Y Global information infrastructure, Internet protocol aspects and Next Generation Networks Series Z Languages and general software aspects for telecommunication systems
