1、EN 300 462-5-1 VI .I .2 (1998-05) European Standard (Telecommunications series) Transmission and Multiplexing (TM); Generic requirements for synchronization networks; Part 5-1 : Timing characteristics of slave clocks suitable for operation in Synchronous Digital Hierarchy (SDH) equipment STD-ETSI EN
2、 300 462-5-3-ENGL L998 3400855 0337779 702 2 EN 300 462-5-1 V1.1.2 (1 998-05) Reference REN/TM-03017-5-1 (4al99idc.PDF) Kevwords synchronization, timing, transmission ETSI Postai address F-O6921 Sophia Antipolis Cedex - FRANCE Office address 650 Route des Lucioles - Sophia Antipolis Valbonne - FRANC
3、E Siret No 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-prfecture de Grasse (06) No 7803/88 Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 Internet secretariat etsi.fr http:/www.etsi.fr http:/www.etsi.org Copyright Notification No part may be reproduced except as aut
4、horized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. O European Telecommunications Standards Institute 1998. All rights reserved. ETSI STD-ETSI EN 300 4b2-5-L-ENGL 1998 3400855 0317780 424 3 EN 300 462-51 V1.1.2 (1998-05) Contents Intellectu
5、al Property Rights 5 Foreword 5 1 2 3 3.1 3.2 4 5 6 6.1 6.2 6.3 Scope 7 Definitions, symbols and abbreviations . 8 Frequency accuracy 8 Pull-in and pull-out ranges . 8 Noise generation 8 References 7 Definitions . 8 Abbreviations 8 Wander in locked mode . Non-locked wander 9 . . 6.3.1 Output jitter
6、at a 2 048 kHz and 2 O48 kbits interface . 10 6.3.2 Output jitter at a Synchronous Transport Module N (STM-N) interface . 11 7 Noise tolerance . 11 7.1 Jitter tolerance 11 7.2 Wander tolerance . . 12 8 Transfer characteristic 14 9 Transient response and holdover performance 14 9.1 Short-term phase t
7、ransient response . 14 9.2 Long-term phase transient response (holdover) . 15 9.3 Phase response to input signai interruptions . 16 9.4 Phase discontinuity 16 10 Interfaces 16 Annex A (informative): A . 1 A.2 A.2.1 A.2.2 A.2.3 Considerations on bandwidth requirements . 18 Introduction 18 Relevant ne
8、twork requirements and assumptions 18 ITU-T Recommendation G.825 STM-N jitter acceptance . 18 Wander accumulation in a synchronization distribution chain . 18 Phase transients due to automatic timing restoration . 19 ETSI STD-ETSI EN 300 YbZ-S-L-ENGL 1998 E 3P008.55 03L778L 3b0 E 4 EN 300 462-5-1 V1
9、.1.2 (1 998-05) A.3 Conclusion . 20 Annex B (informative): Measurement methods for transfer characteristics . 21 B . 1 Phase step response 21 B.2 Frequency step response 22 B.3 Sinusoidal phase response 23 B.4 White phase noise response (frequency domain) . 23 B.5 White phase noise response (time do
10、main) . 24 Annex C (informative): Information on the SEC noise model . 25 Bibliography . 26 History 27 ETSI STD.ETS1 EN 300 gb2-5-1-ENGL 1998 U 3400855 033?782 2T7 = 5 EN 300 462-5-1 V1.1.2 (1998-05) Intellectual Property Rights IPRs essential or potentially essential to the present document may hav
11、e 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 ETR 314: “lntellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, w
12、hich is available free of charge from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/www.etsi.fr/ipr or http:/www.etsi.org/ipr). Pursuant to the ETSI Interim IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. NO guarantee can be give
13、n as to the existence of other IPRs not referenced in ETR 3 14 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (Telecommunications series) has been produced by the Transmission and Multiplexing (TM) Techn
14、ical Committee. The present document has been produced to provide requirements for synchronization networks that are compatible with the performance requirements of digital networks. It is one of a family of documents covering various aspects of synchronization networks: Part 1-1: Part 2-1: “Synchro
15、nization network architecture“; Part 3-1: Part 4-1: “Definitions and terminology for synchronization networks“; “The control of jitter and wander within synchronization networks“; “Timing characteristics of slave clocks suitable for synchronization supply to Synchronous Digital Hierarchy (SDH) and P
16、lesiochronous Digital Hierarchy (PDH) equipment“; “Timing Characteristics of slave clocks suitable for synchronization supply to Synchronous Digital Hierarchy (SDH) and Plesiochronous Digital Hierarchy (PDH) equipment Implementation Conformance (ICs) Statement“; “Timing characteristics of slave cloc
17、ks suitable for operation in Synchronous Digital Hierarchy (SDH) equipment“; “Timing characteristics of primary reference clocks“; “Timing characteristics of primary reference clocks Implementation Conformance (ICs) Statement “; Part 4-2: Part 5-1: Part 6-1: Part 6-2: Part 7-1: “Timing characteristi
18、cs of slave clocks suitable for synchronization supply to equipment in local node applications“. Parts 1-1, 2-1, 3-1 and 5-1 have previously been published as ETS 300 462 Parts 1,2, 3 and 5, respectively. Additionally, parts 4-1 and 6-1 completed the Voting phase of the Two Step Approval procedure a
19、s ETS 300 462 Parts 4 and 6, respectively. It was decided to prepare ICs proformas for several of the parts and this necessitated a re-numbering of the individual document parts. It was also decided to create a new part 7-1. This in turn led to a need to re-publish new versions of all six parts of t
20、he original ETS. At the same time, the opportunity was taken to convert the document type to EN. This has involved no technical change to any of the documents. However part 5-1 has been modified, due to editorial errors which appeared in ETS 300 462-5. - STD.ETS1 EN 300 4b2-5-1-ENGL 1998 m 3400855 0
21、337783 133 6 EN 300 462-5-1 V1.1.2 (1 998-05) Transposition dates Date of adoption of this ETS: 16 August 1996 Date of latest announcement of this ETS (doa): 31 December 1996 Date of latest publication of new National Standard or endorsement of this ETS (dople): 30 June 1997 Date of withdrawal of an
22、y conflicting National Standard (dow): 30 June 1997 NOTE: The above transposition table is the original table from ETS 300 462-5 (September 1996, see History). ETSI 7 EN 300 462-5-1 V1.1.2 (1998-05) This European Standard (Telecommunications series) outlines requirements for timing devices used in s
23、ynchronising network equipment that operates according to the principles governed by the Synchronous Digital Hierarchy (SDH). These requirements apply under the normal environmental conditions specified for SDH equipment. Typical SDH equipment contains a slave clock linked to a master, or a primary
24、reference clock. The logical function of the SEC is described in figure 2 of EN 300 462-2-1 3. In general the SDH Equipment Clock (SEC) will have multiple reference inputs. In the event that all links between the master and the slave clock fail, the equipment should be capable of maintaining operati
25、on (holdover) within the prescribed performance limits contained within the present document. Slave clocks used in SDH equipment shall meet specific requirements in order to comply with the jitter specifications given in ETS 300 417-1-1 9 for plesiochronous tributaries. The case where clock performa
26、nce is required in SDH equipment is outside the scope of the present document, see EN 300 462-4-1 101. 2 Ref e 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
27、 of publication, edition number, version number, etc.) or non-specific. + For a specific reference, subsequent revisions do not apply. + For a non-specific reference, subsequent revisions do apply. + A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN
28、 with the same number. il ETS 300 019: “Equipment Engineering (EE); Environmental conditions and environmental tests for telecommunications equipment“. EN 300 462-1-1 : “Transmission and Multiplexing (TM); Generic requirements for synchronization networks; Part 1-1: Definitions and terminology for s
29、ynchronization networks“. t21 i31 EN 300 462-2-1 : “Transmission and Multiplexing (TM); Generic requirements for synchronization networks; Part 2-1 : Synchronisation network architecture“. 41 IT-T Recommendation G.823: “The control of jitter and wander within digital networks which are based on the
30、2 048 kbitls hierarchy“. i5 1 EN 300 462-6-1 : “Transmission and Mu1 tiplexing (TM); Generic requirements for synchronization networks; Part 6-1: Timing characteristics of primary reference clocks“. ITU-T Recommendation (3.703: “PhysicaUelectrical characteristics of hierarchical digital interfaces “
31、 . t61 t71 ITU-T Recommendation G.825: “The control of jitter and wander within digital networks which are based on the synchronous digital hierarchy (SDH)“. IT-T Recommendation Q.55 1: “Transmission characteristics of digital exchanges“. ETS 300 417-1-1 (1996): “Transmission and Multiplexing (TM);
32、Generic functional requirements for Synchronous Digital Hierarchy (SDH) equipment; Part 1-1: Generic processes and performance“. EN 300 462-4-1: “Transmission and Multiplexing (TM); Generic requirements for synchronization networks; Part 4-1: Timing characteristics of slave clocks suitable for synch
33、ronization supply to Synchronous Digital Hierarchy (SDH) and Plesiochronous Digital Hierarchy (PDH) equipment“. i81 (91 lo1 STD-ETSI EN 300 4b2-5-1-ENGL 1998 D 3is00855 0317785 TOb D 0 EN 300 462-5-1 V1.1.2 (1998-05) 3 3.1 Definitions, symbols and abbreviations Definit ions For the purposes of the p
34、resent document, the definitions given in EN 300 462-1-1 2 apply. 3.2 Abbreviations For the purposes of the present document, the abbreviations given in EN 300 462-1-1 2, together with the following, apply: MTIE NE PDH PLL PPm PRC SDH SEC ssu STM -N TDEV u1 UPP VCO Maximum Time Interval Error Networ
35、k Element Plesiochronous Digital Hierarchy Phase Locked Loop parts per million Primary Reference Clock Synchronous Digital Hierarchy SDH Equipment Clock Synchronisation Supply Unit Synchronous Transport Module N Time Deviation Unit interval Unit Interval peak to peak Voltage Controlled Oscillator 4
36、Frequency accuracy Under free-running conditions, the SEC output frequency accuracy shall be within 4,6 ppm with regard to a reference traceable to a clock as specified in EN 300 462-6-1 5. NOTE: The time interval for this accuracy specification is for further study. 5 Pull-in and pull-out ranges Th
37、e minimum pull-in range shall be f 4,6 ppm, whatever the internal oscillator frequency offset may be. The Pull-out range. is for further study. A value of $r 4,6 ppm has been proposed. 6 Noise generation The noise generation of a SEC represents the amount of phase noise produced at the output when t
38、here is an ideal input reference signal or the clock is in holdover state. A suitable reference, for practical testing purposes, implies a performance level at least 10 times more stable than the output requirements. The ability of the clock to limit this noise is described by its frequency stabilit
39、y. The measures Maximum Time Interval Error (MTIE) and Time Deviation (TDEV) are useful for characterization of noise generation performance. MTIE and TDEV are measured through an equivalent 10 Hz, first order, low-pass measurement filter, at a maximum sampling time to of 1/30 second. The minimum me
40、asurement period for TDEV is twelve times the integration period (T = 12). ETSI STD-ETSI EN 300 462-5-L-ENGL 1998 m 3400855 0327786 792 m Requirement 40 ns 40 7 o,1 ns 25 7 O-Zns 9 EN 300 462-5-1 V1.1.2 (1998-05) Observation interval 0,l 100 s The resultant requirement is shown by the upper solid li
41、ne in figure 2. 6.2 Non-locked wander When a clock is not locked to a synchronization reference, the random noise components are negligible compared to deterministic effects like initial frequency offset. Consequently the non-locked wander effects are included in subclause 9.1. 6.3 Jitter While most
42、 specifications in the present document are independent of the output interface at which they are measured, this is not the case for jitter production; jitter generation specifications shall utilize existing specifications that are currently specified differently for different interface rates. These
43、 requirements are stated separately for the interfaces identified in clause 10. To be consistent with other jitter requirements the specifications are in Unit Interval peak to peak (ipp), where the Unit Interval (Ui) corresponds to the reciprocal of the bit rate of the interface. Due to the stochast
44、ic nature of jitter, the peak-to-peak values given in this clause eventually are exceeded. The requirements shall therefore be fulfilled with a probability of 99 %. 6.3.1 Output jitter at a 2 048 kHz and 2 048 kbits interface In the absence of input jitter, the intrinsic jitter at a 2 O48 kHz or 2 0
45、48 kbit/s output interface as measured over a 60 seconds interval shall not exceed 0,05 Ulpp when measured through a band-pass filter with comer frequencies at 20 Hz and 100 kHz each with a first order 20 dB/decade roll-off characteristic. ETSI STD-ETSI EN 300 4b2-5-2-ENGL 2998 3400855 0337788 715 I
46、ntertace I Measurlng filter 11 EN 300 462-5-1 V1.1.2 (1998-05) Peak-to-peak amplitude 6.3.2 Output jitter at a Synchronous Transport Module N (STM-N) interface STM-1 STM-4 STM-16 In the absence of input jitter at the synchronization interface, the intrinsic jitter at optical STM-N output interfaces
47、as measured over a 60 seconds interval shall not exceed the limits given in table 4. The allowed jitter on an STM-1 electrical interface is for further study. (Hz) (Ui) 500 to 1,3 M 0,50 65 k to 1,3 M 0,lO 1 kto5M 0,50 250 k to 5 M 0,lO 5 k to 20 M 0,50 Requirement 250 ns 4 900 f -1 ns 100 ns Freque
48、ncy interval 1 15 s, exceed the following limit: where : al= 50 nsis (see note i); a2 = 2 O00 nsis (see note 2); b = 1,16 x 10-4 ns/s2 (see note 3); C = 120 ns (see note 4). NOTE 1: The fre uency offset al represents an initial frequency offset corresponding to -8 5 x 10 (0,05 ppm). NOTE 2: The freq
49、uency offset a2 accounts for temperature variations after the clock went into holdover and corresponds to 2 x to the phase error. (2 pprn). If there are no temperature variations, the term a 2 S should not contribute NOTEi 3: The drift b is caused by ageing: 1,16 x lo4 ns/s2 corresponds to a frequency drift of 1 x lo-* /day (0,Ol ppdday). This value is derived from typical ageing characteristics after 10 days of continuous operation. It is not intended to measure this value on a per day basis as the temperature e
