1、 TIA-470.120-C (Revision of TIA-470-B) February 2011Telecommunications Telephone Terminal Equipment Transmission Requirements for Analog Speakerphones ANSI/TIA-470.120-C 2011 APPROVED: FEBRUARY 7, 2011 NOTICE TIA Engineering Standards and Publications are designed to serve the public interest throug
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6、ore its use. (From Project No. 3-4350.120-RV3, formulated under the cognizance of the TIA TR-41 User Premises Telecommunications Requirements, TR-41.3 Subcommittee on Analog and Digital Wire line Terminals. . Published by TELECOMMUNICATIONS INDUSTRY ASSOCIATION Standards and Technology Department 25
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22、ES IS A FUNDAMENTAL ELEMENT OF THE USE OF THE CONTENTS HEREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. ANSI/TIA-470.120-C i TABLE OF CONTENTS 1 SCOPE 1 2 NORMATIVE REFERENCES. 2 3 ABBREVIATIONS, ACRONYMS, AND DEFINITIONS. 3 3.1 Abbreviations and Acronyms.3 3.2 Defi
23、nitions4 4 TECHNICAL REQUIREMENTS 6 4.1 Categories of Criteria .6 4.2 General Testing Considerations .6 4.3 Test Circuits and Setups.6 4.3.1 General Send Test Setup6 4.3.2 General receive Test Setup 7 4.3.3 Send Testing Circuit with Artificial Lines.7 4.3.4 Receive Testing Circuit with Artificial Li
24、nes8 4.3.5 DC Feed Circuit .8 4.3.6 Termination Impedance .10 4.3.7 Source Impedance10 4.3.8 Artificial Lines.10 4.4 Transmission Performance .11 4.4.1 Send Performance 11 4.4.2 Receive Performance .19 ANNEX A (NORMATIVE) NOISE CURVES 26 A.1 Send Noise Curves .26 A.2 Receive Noise Curve28 ANNEX B (N
25、ORMATIVE) CALCULATION OF LOUDNESS RATINGS 29 B.1 Send Loudness Rating (Handset): 30 B.2 Receive Loudness Rating (Handset): .30 B.3 Sidetone Masking Rating (Handset): .31 ANNEX C (NORMATIVE) ISO R-40 FREQUENCIES 33 ANNEX D (INFORMATIVE) LOSS PLAN AND LOUDNESS RATING REFERENCES AND HIERARCHY. 35 ANNEX
26、 E (INFORMATIVE) - BIBLIOGRAPHY. 36 ANNEX F (INFORMATIVE) BNR STUDY. 37 F.1 Objectives.37 F.2 Apparatus37 F.3 Procedure37 F.4 Preliminary Results 37 ANSI/TIA-470.120-C ii F.5 Recommendations 38 F.6 Table of Results38 ANNEX G (INFORMATIVE) ITEMS FOR FUTURE CONSIDERATION . 40 G.1 Voice Switching Perfo
27、rmance40 G.1.1 Single Talk Performance40 G.1.2 Double-Talk Performance40 G.2 Acoustic Echo Canceller Performance.41 G.2.1 Round Trip Echo Path Delay .41 G.2.2 TCL Single Talk 41 G.2.3 Convergence Time.41 G.2.4 TCL Temporally Weighted Coupling Loss - Double Talk41 G.2.5 Send Speech Attenuation During
28、 Double Talk41 G.2.6 Receive Speech Attenuation During Double Talk.41 G.2.7 Send Speech Front-end Clipping Time During Double Talk 41 G.2.8 Receive Speech Front-end Clipping Time During Double Talk .41 G.2.9 Acoustic Stability (TCL: Terminal Coupling Loss) 41 G.2.10 Stability Related to Low Level St
29、imulus.41 G.3 Dynamic Send Background Noise Suppression.41 G.4 Switching operation between speakerphone & handset mode .41 G.5 Send Level and Send Level Directionality.42 G.5.1 Send Level .42 G.5.2 Send Level Directionality (SLD).43 ANSI/TIA-470.120-C iii Table of Figures Figure 1 General Test Setup
30、 For Send Measurements 6 Figure 2 General Test Setup For Receive Measurements. 7 Figure 3 Test Circuit For Send Measurements . 7 Figure 4 Test Circuit For Receive Measurements. 8 Figure 5 One Possible dc Feed Circuit 9 Figure 6 Artificial Line Segment 10 Figure 7 Send Frequency Response Limits for 2
31、.7 km. 12 Figure 8 Speakerphone Send LR Directionality Measurement Setup 15 Figure 9 Speakerphone Receive Level Directionality Measurement Setup 21 Figure 10 Receive Frequency Response Limits for 2.7 km 23 Figure A.1 Psophometric and C-Message noise weighting curves comparison . 27 Figure A.2 A-weig
32、hting noise weighting curve 28 Figure D.1 Hierarchical Relationship between Loudness Rating and Loss Plan Standards . 35 Figure G.1 Proposed Speakerphone Send Level Directionality Measurement Setup. 44 ANSI/TIA-470.120-C iv Table of Tables Table 1 Artificial Line Segment Component Values 10 Table 2
33、Send Frequency Response Limits 12 Table 3 Send Loudness Rating (SLR) Limits . 13 Table 4 Send Loudness Rating Directionality Limits. 14 Table 5 Limits for Send SDNR vs Frequency 16 Table 6 Limits for Send SDNR vs Level 16 Table 7 Send SDNR Stimulus Center Frequencies and Band Limits . 16 Table 8 Sen
34、d SDNR Analysis Notch Frequency Band. 17 Table 9 Speakerphone Receive Level Limits 19 Table 10 Receive Level Directionality Limits 20 Table 11 Mandatory Receive Frequency Response Limits. 22 Table 12 Limits for Receive SDNR vs Frequency 23 Table 13 Limits for Receive SDNR vs Level . 23 Table 14 Rece
35、ive SDNR Stimulus Center Frequencies and Band Limits 24 Table 15 Receive SDNR Analysis Notch Frequency Band 24 Table A.1 Psophometric weighting curve Table A.2 C-Message weighting curve 26 Table A.3 A-weighting curve . 28 Table B.1 ITU-T P.79 Tables 1, 2 and 3, Weighting factors for calculating loud
36、ness ratings . 32 Table C.1 ISO R-40, ISO R-10,1/12thOctave and 1/3rdOctave Frequencies . 33 Table C.2 ISO R-40, ISO R-10,1/12th Octave and 1/3rd Octave Frequencies (Continued) 34 Table F.1 Room noise 35 dBA User Acceptance Levels 38 Table F.2 Room noise 45 dBA User Acceptance Levels 39 Table F.3 Ro
37、om noise 55 dBA User Acceptance Levels 39 Table G.1 Proposed Speakerphone Send Level Limits. 42 Table G.2 Proposed Send Level Directionality Limits. 43 ANSI/TIA-470.120-C v FOREWORD (This foreword is not part of this Standard.) This document is a TIA Telecommunications standard produced by Working G
38、roup TR-41.3.10 of Committee TR-41. This standard was developed in accordance with TIA procedural guidelines, and represents the consensus position of the Working Group and its parent Subcommittee TR-41.3, which served as the formulating group. There are seven annexes in this Standard. Annex A, Anne
39、x B and Annex C are normative and are considered part of this Standard. Annex D, Annex E, Annex F and Annex G are informative and are not considered part of this Standard. The leadership of the TR-41.3.10 Working Group (Chair: Al Baum, Uniden) acknowledges the written contributions provided by the f
40、ollowing individuals in the development of this standard. Organization Representative TIA-470.120-C Uniden Al Baum 9 Editor AST Technology labs, Inc Don McKinnon 9 Editor Acoustics for Communications Ron Magnuson 9 Advent Instruments Dave Stenner 9 Atlinks Fred Bonhomme 9 Consultant in Electroacoust
41、ics John Bareham 9 CenturyLink Amar Ray 9 Listen Inc. Dan Foley 9 MWM Acoustics Glenn Hess 9 Nortel Miguel DeAraujo 9 Texas Instruments Tom Harley 9 VTech Communications Steve Whitesell 9 Suggestions for improvement of this standard are welcome. They should be sent to: Telecommunications Industry As
42、sociation Engineering Department Suite 300 250 Wilson Boulevard Arlington, VA 22201 ( http:/www.tiaonline.org ) ANSI/TIA-470.120-C 1 Telephone Terminal Equipment Transmission Requirements for Analog Speakerphones 1 SCOPE This standard provides speakerphone acoustic performance requirements for Custo
43、mer Premises Equipment (CPE) intended for analog connection to the Public Switched Telephone Network (PSTN). These requirements should ensure compatibility and satisfactory performance to the user in a high percentage of installations. Test measurement methods reference procedures in IEEE Std 1329 w
44、here applicable. This document proposes or references at least one measurement procedure for each technical requirement. However, these procedures are not exclusive. Any measurement procedure and equipment that can result in an identical measurement is considered valid. While the procedures may call
45、 out specific test points within the requirements, the full range of the requirements take precedent. This standard is primarily intended to be used for evaluating single user speakerphones normally used at a distance of one half meter or closer. These requirements are not intended for Cordless hand
46、set speakerphones or multi-user conference speakerphones. ANSI/TIA-470.120-C 2 2 NORMATIVE REFERENCES The following standards contain provisions, which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standard
47、s are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. ANSI and TIA maintain registers of currently valid national standards. ANSI/IEEE Std 1329-1999 Standard met
48、hod for measuring transmission performance of handsfree telephone sets ANSI/IEEE Std 269-2002 Standard methods for measuring transmission performance of analog and digital telephone sets, handsets and headsets ANSI S1.4-1983 (Reaff. 2006) American National Standard Specification for sound level mete
49、rs ANSI S1.12-1967 (Reaff. 1997) American National Standard Specifications for Laboratory Standard Microphone ITU-T Recommendation O.41 (10/94) Psophometer for use on telephone-type circuits ITU-T Recommendation P.50 (9/99) Artificial Voices ITU-T Recommendation P.51 (8/96) Artificial Mouth ITU-T Recommendation P.56 (3/93) Objective Measurement of Active Speech Level ITU-T Recommendation P.79 (11/07) Calculation of loudness ratings for telephone sets ANSI/TIA-4
