1、 TECHNICAL REQUIREMENTS ATIS-TRQ.10.2009 SPLITTERS USED FOR LINE SPLITTING AND LINE SHARING APPLICATIONS ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-driven standards for the information, entertainment and communic
2、ations industry. More than 250 companies actively formulate standards in ATIS 20 Committees, covering issues including: IPTV, Service Oriented Networks, Home Networking, Energy Efficiency, IP-Based and Wireless Technologies, Quality of Service, Billing and Operational Support. In addition, numerous
3、Incubators, Focus and Exploratory Groups address emerging industry priorities including “Green”, IP Downloadable Security, Next Generation Carrier Interconnect, IPv6 and Convergence. ATIS is the North American Organizational Partner for the 3rd Generation Partnership Project (3GPP), a member and maj
4、or U.S. contributor to the International Telecommunication Union (ITU) Radio and Telecommunications Sectors, and a member of the Inter-American Telecommunication Commission (CITEL). For more information, please visit . Notice of Disclaimer these are designated by the words “shall,” “should” and “may
5、,” respectively. The word “will” is used only to designate events that will take place under some defined set of circumstances. Suggestions for improvements of this document are welcomed. They should be sent to the Alliance for Telecommunications Industries Solutions, 1200 G Street, NW, Suite 500, W
6、ashington, DC 20005. The Alliance for Telecommunication Industry Solutions (ATIS) serves the public through improved understanding between carriers, customers, and manufacturers. The Network Interface, Power, and Protection Committee (NIPP) - formerly T1E1 - develops and recommends standards and tec
7、hnical reports. The standards and technical reports are related to power systems, electrical and physical protection for the exchange and interexchange carrier networks, and interfaces associated with user access to telecommunications networks. At the time of initiation or issuance of the letter bal
8、lot for this document, NIPP, which was responsible for its development, had the following roster: E. Eckert, NIPP Chair K. Sievert, NIPP Vice-Chair C. Underkoffler, ATIS Chief Editor C. Posthuma, NIPP Technical Editor Organization Represented Name of Representative Actelis Networks Inc. Ioannis Kane
9、llakopoulos, PhD ADTRAN Inc. Arlynn Wilson Richard Goodson (Alt.) Aktino, Inc. Ray Nagele Michail Tsatsanis (Alt.) Alcatel - Lucent Ken Biholar Tim Pantalis (Alt) ASSIA Inc. Peter Silverman Wonjong Rhee (Alt.) AT however, such features and performance characteristics are beyond the scope of this doc
10、ument. 1.2 Purpose This TRQ is intended to facilitate the provisioning of various digital subscriber line (DSL) technologies and voice-band services over the same loop. The document is written broadly to permit the LSS to be used for current DSL technologies and potential new DSL technologies that u
11、se the same frequency spectra. 1.3 Other Considerations Network systems apply various electrical signals to the subscriber loop for the purpose of network maintenance and alerting the customer of an incoming call. These signals vary considerably in amplitude and can reach values of -/+ 200Vdc for ma
12、intenance functions and 276.2 volts peak for alerting signals. When these signals are applied to an access line that also has a Network Equipment Facility LSS wired in series with the subscriber loop, the low pass section of the splitter may see the full magnitude of these signals. Therefore, consid
13、eration should be given to the selection of circuit components used for the LSS design. During the times these signals are applied, it is acceptable that the low pass filter does not perform all of its functions nor meet the all of the technical requirements in this document. However, the filter com
14、ponents should not be permanently damaged. Such phenomena as lightning and over voltage due to inductive interference or power cross lie beyond the scope of this TRQ. The detailed technical parameters of the network maintenance and alerting signals referenced here can be found in the informative ref
15、erences in clause 7. 2 REFERENCED STANDARDS The following standards contain provisions that, through reference in this text, constitute provisions of this technical requirements document. At the time of publication, the editions indicated were valid. All standards are subject to revision, and partie
16、s to agreements based on this document are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. ATIS-TRQ.10.2009 2 ATIS-0600413.2009, Network to Customer Installation Interfaces Asymmetrical Digital Subscriber Line (DSL) Metallic Interface.
17、1T1.417-2003 (R2007), Spectrum Management for Loop Transmission Systems.1T1.424-2004 (R2009), Trial Use Interface Between Networks and Customer Installations Very-High Speed Digital Subscriber Lines (VDSL) Metallic Interface.1IEEE Standard 455, IEEE Standard Test Procedure for Measuring Longitudinal
18、 Balance of Telephone Equipment Operating in the Voice Band, 1985 or later.2IEEE Standard 743, IEEE Standard Equipment Requirements and Measurement Techniques for Analog Transmission Parameters for Telecommunications, 1995.2GR-57-CORE Issue: 01 2001-10-19, Functional Criteria for Digital Loop Carrie
19、r Systems.3GR-507-CORE Issue: 01 2000-06-30, Section 7 - Transmission Requirements and Objectives of the LATA Switching Systems Generic Requirements (LSSGR).33 DEFINITIONS, ABBREVIATIONS, ACRONYMS gain is negative value. Table 2 - Increase in Attenuation Distortion in Voice Band-Type A 0.2 - 3.4 kHz
20、 3.4 - 4.0 kHz Short loop Type A Splitter ZTc = 900 ZTr = 600 +1.5 -1.5 +2.0 -2.0 Long loop Type A Splitter ZTc = 900 ZTr = 600 +0.5 -1.5 +1.0 -1.5 Figure 7 defines the test configuration and the value of the test components that shall be used for transmission measurements in the voice band for the
21、line sharing splitter. LPFTestLoopZTc(900ohm)TestEq uipm entZHP-c(load)ZTr(600ohm)PSTN U-C U-RSIGCO POTS Splitter0.12uF *ZTc is the NormalTermination in TestSetDSLFigure 7 - Transmission Measurements in Voice Band for the Line Sharing Splitter-Type A NOTES: 1. ZTc = 900 ohm. 2. ZTr = 600 ohm. 3. ZHP
22、-C is the impedance presented to the PSTN connection by a TU-C through the capacitance of the splitter DC blocking capacitors. 4. (*) These capacitors are only for the external Line-sharing splitter without the HPF function. Internal splitter function or external splitters with a complete HPF functi
23、on may incorporate this capacitance in the input to the HPF function. ATIS-TRQ.10.2009 10 4.7.1.4 Envelope Delay Distortion The envelope delay distortion of the line sharing splitter shall be measured using Figure 7. The increase in delay distortion caused by the line sharing splitter as measured fr
24、om the PSTN port to the U-R interface for each of the test loops shall be less than the values in Table 3. Table 3 - Increase in Envelope Delay Distortion-Type A 0.6 - 3.2 kHz 0.2 - 4.0 kHz Short loop Line Sharing Splitter ZTc = 900 ZTr = 600 200 sec 250 sec Long loop Line Sharing Splitter ZTc = 900
25、 ZTr = 600 200 sec 250 sec 4.7.1.5 Return Loss Figure 8 defines the test configuration and the value of the test components that shall be used for impedance measurements in the voice band for the line sharing splitter unit. Return Loss measurements shall be made in accordance with IEEE Standard 743.
26、 LPFSIGZHP-c600OhmTest EquipmentZNL-cPOTS Splitter at COPSTN U-C0.12 uF. *(used only at COtermination)DSLReturn loss referenceimpedanceTermination(Use real OSP cableor a DSL linesimulator)Figure 8 - Line Sharing splitter Return Loss Set Up-Type A NOTES: 1. ZNL-c = 800 ohm in parallel with the series
27、 connection of a 100 ohm resistor and a 50 nF capacitor (non-loaded loop model seen from CO). This value comes from the Telcordia LSSGR as a reference compromise impedance for non-loaded cable. 2. ZHP-C is the impedance presented to the PSTN connection by a TU-C through the capacitance of the Line-s
28、haring splitter DC blocking capacitors. 3. (*) These capacitors are for the external Line-sharing splitter without the HPF function only. Internal Splitter function or external splitters with a complete HPF function may incorporate this capacitance in the input to the HPF function. ATIS-TRQ.10.2009
29、11 The Echo Return Loss (ERL), Singing Return Loss Low (SRL-L), and Singing Return Loss High (SRL-H) shall exceed the values given in Table 4. The Single Frequency Return Loss (SFRL) at any frequency between 2200 Hz and 3400 Hz shall be greater than 2 dB. Table 4 - Return Loss-Type A Zref Zterm ERL
30、(dB) SRL-L (dB) SRL-H (dB) Comments Line Sharing Splitter ZNL-c 600 ohm 8 5 5 Individual frequencies start at 2200 Hz and sweep to 3400 Hz. See IEEE 743-1995, Section 8.4 4.7.1.6 Intermodulation Distortion The intermodulation distortion contributed by the LSS LPF shall be measured using the test con
31、figuration of Figure 7 and the null loop. With an applied tone set per IEEE 743, at a level of -9 dBm, the second and third order intermodulation distortion products shall be at least 57 dB and 60 dB, respectively, below the received signal level. Test shall be made in accordance with IEEE Standard
32、743. 4.7.2 Longitudinal Balance of Line Sharing Splitter The longitudinal balance of the line sharing splitter can be measured using two different techniques. One technique would be to treat the line sharing splitter as a separate entity that would require using the two-port testing technique. The o
33、ther technique that can be used to test the line sharing splitter would be to treat it, the TU-C, and line card combination as a one-port network. This one-port network would require using the one-port testing technique. Tests should be made according to IEEE Standard 455. 4.7.2.1 Longitudinal Balan
34、ce of Line Sharing Splitter using Two-Port Testing Technique This method shall be used to test a line sharing splitter when it is treated as a separate entity. The longitudinal balance of the line sharing splitter (without loops) measured in either direction between the PSTN and line port, as a two-
35、port device, shall be measured in accordance with IEEE Standard 455. In the case where DC blocking capacitors are included as part of the splitter function on the DSL port, the DSL port will be shorted. Otherwise, the DSL port shall be open. Because of the maintenance signatures, the applied longitu
36、dinal voltage shall be maximum 3.0 V p-p. The balance shall be greater than 58 dB for frequencies between 200 Hz - 1 kHz with a straight-line level decreasing to 53 dB at 3 kHz. The requirements shall be met at all DC bias currents between 25mA and 100 mA. The termination of the test set is set for
37、series-balance measurement per IEEE Standard 455. Prior to testing, a test circuit balance (calibration) of 77 dB (58 + 19 dB) shall be achieved to ensure 1 dB accuracy. Figure 9 shows the test setup for the external line sharing splitter. The DSL port is shorted. If testing longitudinal balance on
38、an integrated line sharing modem, the TU-C shall be connected but powered down. ATIS-TRQ.10.2009 12 LPF S I G DSL Port PSTN 0.12 uF 0.12 uF Line Port Shorted LB Test Source LB Test Load Figure 9 - Longitudinal Balance CO Test Setup per IEEE 455-Type A 4.7.2.2 Longitudinal Balance of Line Sharing Spl
39、itter using One Port Testing Technique This method shall be used to test a line sharing splitter when the splitter, TU-C, and line card combination is treated as a one-port network. The longitudinal balance of the combined line sharing splitter, TU-C, and Line card (without loops) shall be measured
40、in accordance with IEEE Standard 455. Because of the maintenance signatures, the applied longitudinal voltage shall be maximum 3.0 V p-p. A suitable 130 to 1300 Ohm variable DC hold circuit shall be used to sink DC current from the 1 port assembly at the line port. The balance shall be greater than
41、52 dB for the frequencies between 200 Hz to 3.0 kHz. Requirements shall be met at all currents between 25 mA and 100 mA. Prior to testing, a test circuit balance (calibration) of 71 dB (52+ 19 dB) shall be achieved to ensure 1 dB accuracy. Figure 10 shows the test setup for the combined line sharing
42、 splitter, TU-C, and line card combination one-port network. Figure 10 - Longitudinal Balance CO Test Set-up for One-Port Network per IEEE 455-Type A 4.7.3 Transparent Testing Capacitance To minimize the effect of the splitter on the performance of metallic loop test systems, the input impedance is
43、defined for a special narrow frequency band. ATIS-TRQ.10.2009 13 4.7.3.1 Tip to Ring Capacitance The intent of this requirement is to limit the maximum capacitance seen by metallic line testing systems. By setting this limit, the metallic test systems can still test PSTN services with the accuracy a
44、nd dependability they have today. Overall, the admittance of the PSTN port shall be capacitive. The capacitance present at the PSTN interface in the frequency range of 17 - 33 Hz shall be a maximum of 300 nF. This amount includes the combined total capacitance due to the two splitters at the network
45、 end and the remote end with attached modems. The following maximum/minimums shall be met: Line Sharing splitter without the modem connected: o 115 nF Max o 20 nF Min Modem input allowance, including the DC blocking capacitors at the CO end: o 35 nF Max o 20 nF Min Modem with integral line sharing s
46、plitter function or external line sharing splitter with both HPF and LPF functions, are the sum of the above: o 150 nF Max o 40 nF Min Figure 11 - Capacitance Test-Type A 4.7.3.2 Capacitance to Ground There should be no designed AC path to ground. In order to maintain the ability to test accurately,
47、 the maximum stray capacitance-to-ground from either leg of the line sharing splitter shall be less than 1.0 nF. 4.8 DSL Band Testing 4.8.1 DSL Band Attenuation The insertion loss of the splitter and ZHP (i.e., the difference in attenuation measured with and without the splitter/ZHP combination inse
48、rted) when measured as shown in Figure 12 shall be greater than 65 dB from 32 to 300 kHz and greater than 55 dB from 300 to 1104 kHz with an input level of 10 dBm. ATIS-TRQ.10.2009 14 LPFSIGDSL PortPSTN0.12 uF0.12 uFLine PortVm900 ohmHi ZSource 100 ohm32kHz 1104kHzBalancedExternal CO POTS splitter w
49、ithout HPFZHPcFigure 12 - Measurement of the Line Sharing Splitter Attenuation in the DSL Band-Type A 4.8.2 Input Impedance (Loading of DSL Signal Path) The insertion loss caused by the LPF in the band from 32 to 1104 kHz between nominal impedances with an input level of -10 dBm, as shown in Figure 13 shall be no more than 0.25 dB. LPFSIGDSL PortPSTN0.12 uF0.12 uFLine Port100 ohm Load900 ohmSource 100 ohm32kHz 1104kHzBalancedVmFigure 13 - Measurement of Loading Effect of Line Sharing Splitter in the DSL Band-Type A 5 TYPE B NETWORK EQUIPMENT FACILIT
