ATIS 0600005-2006 Acoustic Measurement.pdf

1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0600005.2006(R2011) Acoustic Measurement 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 communications i

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11、of Disclaimer however, only the editions cited are applicable for this standard. 1 ETSI 300 753, Equipment Engineering (EE); Acoustic Noise Emitted by Telecommunications Equipment.12 GR-63- CORE, NEBS Requirements: Physical Protection, Issue 2.21This document is available from the European Telecommu

12、nications Standards Institute (ETSI). ATIS-0600005.2006 2 3 ANSI S12.10, Acoustics Measurement of Airborne Noise Emitted by Information Technology and Telecommunications Equipment.34 ANSI S12.12, Engineering Method for the Determination of Sound Power Levels of Noise Sources Using Sound Intensity.35

13、 ANSI S12.54, Acoustics- Determination of Sound Power Level of Noise Source Using Sound Pressure- Engineering Method in an Essentially Free Field Over a Reflecting Plane.36 T1.336-2003, Engineering Requirements for a Universal Telecom Framework.47 ISO/IEC 17025, General requirements for the competen

14、ce of testing and calibration laboratories.58 ASTM E380-92, Standard practice for the use of the international system of units (SI) (The Modernized Metric System)63 DEFINITIONS The following definitions are taken from ANSI S12.10 3, ETSI 300 753 1, ANSI 12.12 4, and ANSI T1.336-2003 6. 3.1 A-weighti

15、ng filter: Response characteristic of a filter used in acoustic measurement system that attenuates low frequency and high frequency acoustic energy. This filter is used to provide a frequency response characteristic similar to that of the human auditory system. 3.2 Air Moving Devices: Devices that c

16、hange the velocity and/or direction of air. 3.3 Central office: An environmentally controlled space in which a telecommunications network facility switching system and other associated operating systems are installed. 3.4 Environmentally controlled: A condition of maintaining temperature and humidit

17、y within prescribed limits. 3.5 Equipment: A shelf, chassis, or other apparatus that operates to provide a design function either standalone or with other equipment. 3.6 Equipment assembly: A unit of electronic hardware, typically including subassemblies. 3.7 Frame: Synonymous with rack; generally d

18、oes not have doors. 3.8 Network telecommunications facility: A dedicated space for housing equipment for receiving, switching, or transmitting telecommunication signals within a network. 3.9 Shelf: An assembly that mounts directly to uprights in a frame without the need for additional structural sup

19、port. 2Telcordia documents are available from Industry Direct Sales, Telcordia, 8 Corporate Place, PYA 3A-184, Piscataway, NJ, 08854-4156, or: 3This document is available from ANSI at . 4This document is available from the Alliance for Telecommunications Industry Solutions (ATIS), 1200 G Street N.W.

20、, Suite 500, Washington, DC 20005. 5This document is available from the International Organization for Standardization. 6This document is available from the American Society for Testing and Materials (ASTM), 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, Phone: (610) 832-9585, Fax: (610) 8

21、32-9555, . ATIS-0600005.2006 3 3.10 Sound intensity: The sound intensity in a specified direction at a point is the average rate of sound energy transmitted in the specified direction through a unit area normal to this direction at the point considered. 3.11 Sound power level: Ten times the logarith

22、m (base 10) of the ratio of a given sound power to the reference sound power. The weighting network (A-weighting) or the width of the frequency band used needs to be indicated. The reference sound power is 1 pW. Units: dBA. 3.12 Sound pressure level: Ten times the logarithm (base 10) of the ratio of

23、 the time-mean-square sound pressure to the square of the reference sound pressure. The weighting network (A-weighting) or the width of the frequency band used needs to be indicated. The reference sound pressure is 20 Pa. Units: dBA. 3.13 Subassembly: A set of components designed for a particular us

24、e. 4 ACRONYMS AND ABBREVIATIONS ANSI American National Standards Institute ASTM American Society for Testing and Materials CO Central Office cm centimeter SI International System of Units 5 MEASUREMENT METHODOLOGY One of the two measurement methods specified in ANSI S12.10 3 or the sound intensity m

25、ethod described in ANSI S12.12 4 shall be used for determining the sound power level for equipment under test. The measurement methods are as follows: Reverberation; Free-field over reflecting plane (Engineering or Precision method); and Sound intensity. 6 UNITS OF MEASURE Units of measure in this s

26、tandard are shown in both SI and American Standard Units. Where a unit of measure is followed by a value enclosed in parentheses, the second value may be a mathematical approximation of the first value. 7 EQUIPMENT CONFIGURATION The telecommunications equipment shall be tested in a representative co

27、nfiguration that simulates the maximum expected acoustic noise for the environmental conditions described in this standard. ATIS-0600005.2006 4 8 ACOUSTIC NOISE EMISSION LIMITS The maximum acoustic noise emission limits for telecommunications equipment to be installed in temperature-controlled envir

28、onments are specified in Table 1. Table 1: Maximum Acoustic Noise Emission Limits for Telecommunications Equipment in Temperature-Controlled Environments Environmental Description Sound Power Level, dBA Temperature, C* Class 1 Telecommunication equipment room (unattended) 75 27 Class 2 Telecommunica

29、tion equipment room (attended) 75 27 Power room 87 27 * Maximum acoustic level that occurs between 23C and 27C should be measured (see methodology, section 9.1 for clarification). 9 TESTING METHODOLOGY 9.1 Procedure for Nominal Operating Conditions Sound power measurements taken between 23C and 27C

30、can be obtained using one of two methods. In the first method, the ambient temperature in the test environment shall be set at the test requirement temperature of 27C (consideration for test room temperature variation shall be taken into account when making measurements). In the second method, the a

31、mbient temperature in the test environment shall be 23C 2C, but the air moving devices within the equipment under test shall be set to the level that the devices would run at when the equipment is operating in an ambient temperature equal to 27C. The recorded acoustic output value shall be the maxim

32、um equal to or between 23 and 27C. Cooling device hysteresis shall be taken into account when determining maximum cooling device acoustic level at test temperature (see Annex D for explanation). 9.2 Procedure for Maximum Acoustic Output The ambient temperature in the test environment shall be 23C 2C

33、, but the air moving devices within the equipment under test shall be set to produce the maximum acoustic output level that the devices will produce in an environment from 27C up to and including 55C. The data shall be recorded and the results provided in a test report, if required. 10 RETEST OF REV

34、ISED EQUIPMENT Technical justification shall be documented by the manufacturer to avoid retest. ATIS-0600005.2006 5 Annex A (informative) A RATIONALE FOR SOUND POWER MEASUREMENT For many years, the telecommunication industry has been discussing the best way to measure acoustic noise from communicati

35、ons equipment. Both of the methods investigated (source sound power and sound pressure) have advantages and disadvantages. However, in the last decade, the telecommunications industry has worked towards the development of product noise standards that measure source sound power as an alternative to s

36、ound pressure (see GR-63-CORE, Issue 2, Section 4.6 2 where sound power is cited as a future goal). This shift has taken place largely because “sound power test methods are far less susceptible to ambiguities than sound pressure test methods.” 1 The lack of ambiguity that occurs within the measureme

37、nt of sound power makes it easier and more accurate to measure the noise emission of different systems of devices and gives a better and fairer comparison. While this standard focuses on sound power as the preferred method of measuring the emission of acoustic noise from telecommunications equipment

38、, it is necessary to look at why sound pressure is no longer preferred by the industry. While sound power is the preferred testing method in the industry today, sound pressure testing is not totally discounted; however, sound pressure can be a less accurate form of measurement when not performed in

39、a closely controlled and characterized environment. Without properly accounting for the test environment, sound pressure measurements for a given piece of equipment can vary significantly. Additionally, unless a sufficient number of measurement locations is taken, the noise emitted may not be fully

40、captured due to directionality effects. Because it is difficult to consistently measure sound pressure under the testing methodology set by GR-63-CORE 2, this standards committee submits that a sound power method is highly preferable, especially as it can be used to estimate the sound pressure level

41、s in the installed environment given the sound power of the equipment and information about the room conditions. This standard adopts the sound power method described in ANSI S12.10 (ISO 7779) 3, that provides complete measuring and reporting methodologies. This method was adopted by ETSI (European

42、Telecom Standard Institute) in 1997 as a foundation for their sound power testing requirements. Though much of the American telecommunications market currently uses sound pressure measurements it is the decision of this standards body that a shift to sound power measurement is necessary to harmonize

43、 with the international community and to provide the most accurate and repeatable results. ATIS-0600005.2006 6 Annex B (informative) B EXPLANATION OF SOUND POWER DETERMINATION METHODS B.1 Reverberation Rooms When performing sound power testing in a reverberation room, a comparison is made between th

44、e acoustic output of a reference sound source and the equipment under test. The requirements for the reverberation room, procedures for room qualification, reference sound source, ambient conditions, test item placement and instrumentation are given in ANSI S12.10 3. B.2 Equipment Measurements under

45、 Essentially Free Field Conditions over a Reflecting Plane When performing sound power testing under this method, sound pressure level measurements are made at the specified microphone locations around a hypothetical reference surface. The requirements of the measurement environment, procedures for

46、environment qualification, measurement locations, test item placement, and instrumentation are provided in ANSI S12.10 3. This standard recommends that the Engineering Method described in ANSI S12.10 3 (and its associated references) should be used. B.3 Sound Intensity This method provides a procedu

47、re for sound power testing that allows more flexibility in the testing environment. The method employs a sound intensity probe that provides a vector quantity representing the acoustic output of the equipment under test. The vector information can be used to discriminate between the acoustic output

48、of the equipment under test and reflections and background noise. The requirements of the measurement environment, measurement locations, test item placement, and instrumentation are provided in ANSI S12.12 4. ATIS-0600005.2006 7 Annex C (informative) C EMISSION LIMITS The emission limits stated in

49、this standard are derived from issues of perception (such as speech communication and annoyance) rather than hearing loss. Currently, the acoustic output of most telecommunications devices is below the level required to cause hearing damage. ATIS-0600005.2006 8 Annex D (informative) D TEMPERATURE VARIATION IN TEST FACILITY AND COOLING DEVICE HYSTERESES The intent of the requirement is to characterize the noise level of the equipment in a Central Office that may operate to a minimum tempera