ETSI TS 101 952-2-2-2003 Access network xDSL transmission filters Part 2 VDSL splitters for European deployment Sub-part 2 Specification of the high pass part of VDSL POTS splitter.pdf

1、ETS I TS 1 O 1 952-2-2 VI .I .I (2003-03) Technical Specificafion Access network xDSL transmission filters; Part 2: VDSL splitters for European deployment; Sub-part 2: Specification of the high pass part of VDSL/POTS splitters for use at the Local Exchange (LE) and the user side near the Network Ter

2、mination Point (NTP) 2 ETSI TS 1 O1 952-2-2 VI .I .I (2003-03) Reference DTSITM-06028-2-2 Keywords POTS, splitter, testing, VDSL, xDSL ETSI 650 Route des Lucioles F-O6921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 Siret No 348 623 562 00017 - NAF 742 C Association

3、 but non lucratif enregistre la Sous-prfecture de Grasse (06) No 7803/88 Important notice Individual copies of the present document can be downloaded from: http:lwmv.etsi .arq The present document may be made available in more than one electronic version or in print. In any case of existing or perce

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8、Contents Intellectual Property Rights 4 Foreword . 4 1 2 3 4 4.1 5 6 6.1 6.2 7 7.1 Scope 5 References 5 Abbreviations . 6 General functional description of VDSL over POTS splitters . 6 Functional diagram . 6 High pass filter options . 7 High Pass filter implementation . 8 High Pass filter requiremen

9、ts . 9 Option B: lSt order filter . Option C: higher order filter Insertion loss requirements . 8 . 8 . 9 7.1.1 Insertion loss-requirements for options A and B . 9 7.1.2 Insertion loss requirements for option C . 10 7.2 Unbalance about earth requirements for options B . 10 History 12 ETSI 4 ETSI TS

10、1 O1 952-2-2 VI .I .I (2003-03) Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR

11、 O00 3 14: “Intellectual Property Rights (7PRs); Essential, orpotentially Essential, IPRs notlJied to ETSI in respect ofETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (5). All published ETSI deliverables shall include information wh

12、ich directs the reader to the above source of information. Foreword This Technical Specification (TS) has been produced by ETSI Technical Committee Transmission and Multiplexing (TM). AT Analogue of Technical Committee Access and Terminals (AT); and TM6 of Technical Committee Transmission and Multip

13、lexing (TM). The present document is part 2 sub-part 2 of a multi-part deliverable covering different aspects of European specific DSL splitters, as identified below: Part 1 : Part 2: “ADSL splitters for European deployment“; “VDSL splitters for European deployment“; Sub-part 1: “Specification of th

14、e low pass part of VDSL/POTS splitters“; Sub-part 2: “Specification of the high pass part of VDSLROTS splitters for use at the Local Exchange (LE) and the user side near the Network Termination Point (NTP)“; “Specification of VDSL/ISDN splitters for use at the Local Exchange (LE) and the user side n

15、ear the Network Termination Point (NTP)“; Sub-part 3: NOTE: The choice of a multi-part format for this deliverable is to facilitate maintenance and future enhancements. The present document is fully in line with initiative “eEurope 2002 - An Information Society For All“, under “The contribution of E

16、uropean standardization to the eEurope Initiative, A rolling Action Plan“ especially under the key objective of a cheaper, faster and secure Internet. ETSI 5 ETSI TS 1 O1 952-2-2 VI .I .I (2003-03) 1 Scope The present document describes requirements and test methods for DSL splitters. The present do

17、cument specifies requirements and test methods for the high pass part of VDSL over POTS splitters to be used at the Local Exchange and at the user side near the NTP. The present document is derived from TS 101 952-1-2 4, describing requirements for ADSL over POTS splitters. A consequence of this is

18、that the filter described in this document can only be applied to VDSL over POTS in an environment where the VDSL pass band starts around 25 kHz, i.e. the upstream band USO TS 101 270-1 3 is used. The high pass filter described in this document is intended to be used in conjunction with a low pass p

19、art defined in TS 101 952-2-1 5, and with a practical VDSL transceiver impedance defined in 3. If VDSL splitter parts and VDSL transceivers, which are not intended to inter-operate, are combined then severe problems of incompatibility might arise. There are at least two more variants under study for

20、 the high pass filter, and for the related low pass in conjunction with the relevant VDSL impedance: Where the VDSL passband starts at around 138 kHz and the VDSL transceiver impedance is close to the nominal design impedance above 138 kHz, for application in which the USO band is not used. Where th

21、e VDSL passband starts at a frequency higher than around 900 kHz and the VDSL transceiver impedance is close to the nominal design impedance above this frequency, for instance in a cabinet deployment where the band below around 900 kHz is not used in order to be spectrally compatible with ADSL from

22、the Central Office. 2 Re fe re nces The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication andor edition number or version number) or non-specific. For a specif

23、ic reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. Referenced documents which are not found to be publicly available in the expected location might be found at InttD:/doctsox.etsi .o-rpRefercncc. il ETSI EN 300 001: “Attachments to the Public S

24、witched Telephone Network (PSTN); General technical requirements for equipment connected to an analogue subscriber interface in the PSTN“. ITU-T Recommendation 0.9: “Measuring arrangements to assess the degree of unbalance about earth“. 21 31 ETSI TS 101 270-1 : “Transmission and Multiplexing (TM);

25、Access transmission systems on metallic access cables; Very high speed Digital Subscriber Line (VDSL); Part 1 : Functional requirements“. ETSI TS 101 952-1-2: “Access network xDSL transmission filters; Part 1: ADSL splitters for European deployment; Sub-part 2: Specification of the high pass part of

26、 ADSL/POTS splitters“. ETSI TS 101 952-2-1: “Access network xDSL transmission filters; Part 2: VDSL splitters for European deployment; Sub-part 1 : Specification of the low pass part of VDSL/POTS splitters“. 41 51 ETSI 6 ETSI TS 1 O1 952-2-2 VI .I .I (2003-03) 3 Abbreviations For the purposes of the

27、 present document, the following abbreviations apply: CPE DSL ITU LE NTP POTS TE VDSL Customer Premise Equipment Digital Subscriber Line International Telecommunication Union Local Exchange (Central Office) Network Termination Point Plain Old Telephone Service Terminal Equipment (e.g. Telephone, Fax

28、, voice band modem, etc.) Very high speed Digital Subscriber Line 4 General functional description of VDSL over POTS s p I i tte rs The main purpose of the VDSL over POTS splitter filter is to separate the transmission of POTS signals, and VDSL band signals, enabling the simultaneous transmission of

29、 both services on the same twisted pair. The splitter also serves to protect POTS from interference due to egress (and ingress) from VDSL signals. Equally it protects the VDSL transmission from transients generated primarily during POTS signalling (dialling, ringing, ring trip, etc.), and it must al

30、so prevent interference to the VDSL service due to fluctuations in impedance and linearity that occur when telephones change operational state (e.g. from off-hook to on-hook). The splitter filter may be implemented as an independent unit, separately from the VDSL transceiver, or may be integrated wi

31、th the VDSL termination unit. 4.1 Functional diagram The functional diagram for the splitter combination is given in figure 1. POTS POTS 88 B LE-side VDSL transceiver (Central Ofjce) TE-side VDSL transceiver (Customer Premises) Figure 1: Functional diagram of the DSL splitter configuration ETSI 7 ET

32、SI TS 1 O1 952-2-2 VI .I .I (2003-03) The transfer functions between the different ports of the splitter can be understood as follows: The transfer function from the POTS port to the LINE port and vice-versa is that of a low-pass filter. A very high level isolation is required from the VDSL port to

33、the POTS port and vice-versa to prevent undesirable interaction between VDSL and any existing narrowband services. The transfer function from the VDSL port to the LINE port and vice-versa is either that of a high-pass filter, or it may be all pass in nature, in the case where the full high pass filt

34、er function is implemented in the DSL transceiver (see TS 101 952-1-2 4 and the present document). - (Optional High Pass) 4 Figure 2: Structure of the VDSL splitter filter 5 High pass filter options The high pass filter, as referred to in the present document, is the series high pass filter that is

35、located in the splitter unit. It is distinct from the input high pass filter of the VDSL modem, which is located in the VDSL transceiver. Reasons for including a series high pass filter in the LE splitter unit include the following: safety to uncouple the POTS line from damage due to the VDSL servic

36、e; DC decoupling, to avoid “stealing“ POTS service from the premises of an alternative operator; POTS privacy, when VDSL is supplied by an alternative operator, to avoid “listening“. In the case of a CPE filter, the role of the series high pass filter is less important. It provides DC de-coupling be

37、tween the POTS and VDSL, and presents a more controlled impedance to the low pass filter at the VDSL port (e.g. it potentially enables the POTS service to continue functioning in the case of a user short circuiting the VDSL port of the splitter). The high pass filter shall be one of the following op

38、tions: Option A: Oth order filter, i.e. no series high pass filter in the splitter unit; Option B: lSt order filter made up of two blocking capacitors; Option C: Higher order filter. Implementation requirements for options B and C are given in clause 6. Electrical requirements for each option are gi

39、ven in clause 7. ETSI 8 ETSI TS 1 O1 952-2-2 VI .I .I (2003-03) 6 High Pass filter implementation 6.1 Option B: 1st order filter Blocking capacitors CB = 120 nF, with CB as defined by figure 3, shall make up the lSt order high pass filter. i . : Figure 3: Implementation of Ist order high pass filter

40、 A tolerance of 5 % shall be allowed for the practical implementation of these capacitors. Each of these capacitors shall retain their nominal value for DC voltages up to those present in the telephony network as defined in EN 300 O01 i. 6.2 Option C: higher order filter The third order high pass fi

41、lter as defiied by figure 4 shall make up the option C high pass filter. Figure 4: Implementation of 3rd order high pass filter The following values for the electrical representation could be used: CL = 54 nF, CA = 90 nF, L, = 0,38 mH. A tolerance of 5 % shall be allowed for the practical implementa

42、tion of the capacitors. A tolerance of 7 % shall be allowed for the inductor. The impedance network presented in figure 4 is an electrical representation, rather than a circuit diagram. The implementation shall present an equivalent impedance to that shown in figure 4, however derived. NOTE: The ele

43、ctrical representation given in figure 4 is considered to be a satisfactory implementation of the higher order filter. Alternative implementation methods are for further study. ETSI 9 ETSI TS 1 O1 952-2-2 VI .I .I (2003-03) 7 High Pass filter requirements In the case where either option B or option

44、C, as described in clause 6, is present in the splitter unit, the requirements of clause 7 shall be met. The impedances networks shown in figures 5 and 6 are used in some of the test setups for these requirement s. 60 nF 60 nF Figure 5: Schematic diagram 120Q 150Q 634,5 pH 2 47nF 150nF Figure 6: Imp

45、edance Z, 7.1 Insertion loss requirements 7.1 .I Insertion loss requirements for options A and B The insertion loss due to the insertion of the splitter (i.e. both the blocking capacitors and low pass filter in the case of option B) between the LINE port and the VDSL port shall be as specified in ta

46、ble 1. Examples of valid test setups are given in figures 7 and 8. The insertion loss requirements of table 1 are to be met in the case where Z, of figure 7 is a short circuit, an open circuit, and the nominal Z, impedance of figure 6. Table 1 : Insertion loss between LINE and VDSL port for VDSLIPOT

47、S splitters I Frequency range I Insertion loss between LINE and VDSL oort 32 kHz to 50 kHz I c 3 dB 50 kHz to 12 MHz I c 1 dB ETSI 10 (50ohms 1 Balun 50 Q: 135 Q ETSI TS 1 O1 952-2-2 VI .I .I (2003-03) LINE Port VDSL Port 634,5 TO p 135 0 POTS II 60 nF Port , 60nF Splitter Unit 50 kHz to 100 kHz 100

48、 kHz to 12 MHz 135 0 (for further study) (for further study) 135 0: 50 0 - 1 2 3 U ZPOTS VDSL port closed VDSL port open I INF nnri clnsad Figure 7: Example VDSL to LINE insertion loss test setup 60 nF Splitter Unit Signal Source (50 0) LPOTS Figure 8: Example LINE to VDSL insertion loss test setup

49、7.1.2 Insertion loss requirements for option C The insertion loss due to the insertion of the splitter (i.e. both the high pass filter and low pass filter) between LINE port and VDSL port shall be as specified in table 2. Examples of valid test setups are given in figures 7 and 8. The insertion loss requirements of table 2 are to be met in the case where Z, of figures 7 and 8 is a short circuit, an open circuit, and the nominal Z, impedance of figure 6. Table 2: Insertion loss between LINE and VDSL port for VDSLIPOTS splitters 7.2 I Frequency range I Inse