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Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 3241.1-2025: Electroacoustics - Octave-band and fractional-octave-band filters - Part 1: Specifications Status: Valid GB/T 3241.1: Historical versions
Basic dataStandard ID: GB/T 3241.1-2025 (GB/T3241.1-2025)Description (Translated English): Electroacoustics - Octave-band and fractional-octave-band filters - Part 1: Specifications Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: A59 Classification of International Standard: 17.140.50 Word Count Estimation: 38,352 Date of Issue: 2025-05-30 Date of Implementation: 2025-12-01 Older Standard (superseded by this standard): GB/T 3241-2010 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration GB/T 3241.1-2025: Electroacoustics - Octave-band and fractional-octave-band filters - Part 1: Specifications---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order. ICS 17.140.50 CCSA59 National Standard of the People's Republic of China Partially replaces GB/T 3241-2010 Electroacoustic Octave and Fractional Octave Filters Part 1.Specification Part 1.Specifications (IEC 61260-1.2014, IDT) Released on 2025-05-30 2025-12-01 Implementation State Administration for Market Regulation The National Standardization Administration issued Table of contentsPreface III Introduction IV 1 Scope 1 2 Normative references 1 3 Terms and Definitions 2 4 Reference environmental conditions 5 5 Performance requirements 5 5.1 General 5 5.2 octave frequency ratio 6 5.3 Reference frequency 6 5.4 Accurate center frequency 6 5.5 Nominal center frequency 7 5.6 Cut-off frequency 7 5.7 Time-averaged signal level 7 5.8 Filter Attenuation 7 5.9 Reference attenuation 7 5.10 Relative attenuation 8 5.11 Normalized effective bandwidth 10 5.12 Effective bandwidth deviation 11 5.13 Linear operating range 11 5.14 Time-invariant work 12 5.15 Anti-aliasing filter 12 5.16 Sum of output signals 13 5.17 Overload indicator 13 5.18 Filter decay time 13 5.19 Maximum input signal 13 5.20 Output and Terminal Impedance 13 5.21 Power supply check 13 5.22 Sensitivity to various environments 14 5.23 Electrostatic discharge and electromagnetic compatibility requirements 14 6 Instrument logo 16 7 User Manual 17 7.1 Overview 17 7.2 Operation 17 7.3 Test 17 Appendix A (informative) Relationship between tolerance interval, corresponding acceptance interval and maximum permissible measurement uncertainty 18 Appendix B (Normative) Maximum permissible expanded measurement uncertainty 19 Appendix C (Informative) Example of conformity assessment of this document specification 20 C.1 Overview 20 C.2 Compliance criteria 20 C.3 Test results example 20 Appendix D (Informative) Base 2 Filters 22 Appendix E (Informative) Nominal center frequency 23 E. Center Frequencies of 1-Octave and One-Third-Octave Filters 23 E.2 Center frequency of half-octave filter 24 E.3 Center frequencies of other bandwidths 24 Appendix F (informative) Normalized frequencies at the turning points of the minimum and maximum relative attenuation acceptance limits for one-third octave band filters Appendix G (Informative) Filter response to exponentially swept sine signals 27 G.1 Exponential Frequency Sweep 27 G.2 Response of a Bandpass Filter Bank to Sweep 27 Appendix H (Informative) Measurement of filter decay time 30 H.1 Overview 30 H.2 Measurement of filter decay time 30 Reference 31 Figure 1 Minimum and maximum limits on relative attenuation as a function of f/fm for 1- and 2-order octave-band filters 10 Figure A.1 Relationship between tolerance interval, corresponding acceptance interval and maximum permissible measurement uncertainty 18 Figure C.1 Conformity assessment example 21 Figure G.1 Relationship between logarithmic frequency coordinate and linear time coordinate during exponential scanning 29 Table 1 Acceptance limits of relative attenuation of octave band filters 8 Table 2 RF disturbance limits for Class B information technology equipment (ITE) at a distance of 10m 16 Table 3 Limits for conducted disturbances from public power supply voltage 16 Table B.1 Maximum allowable expanded measurement uncertainty 19 Table C.1 Conformity evaluation example 20 Table E.1 Centre frequencies of octave and one-third octave band filters in the audio frequency range 23 Table F.1 Acceptance limits for relative attenuation of one-third octave band filters 25ForewordThis document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1.Structure and drafting rules for standardization documents" Drafting. This document is part 1 of GB/T 3241 "Electroacoustic octave and fractional octave filters". GB/T 3241 has been published The following parts. --- Part 1.Specification; --- Part 2.Type evaluation test. This document partially replaces the relevant terms and definitions, properties and specifications in GB/T 3241-2010 "Electroacoustic octave and fractional octave filters" Compared with the relevant contents of GB/T 3241-2010, in addition to structural adjustments and editorial changes, the main changes are. The technical changes are as follows. a) The scope of application has been changed (see 1.2, 1.2 of the.2010 edition); b) The design objectives have been changed (see 1.3, 5.2, and 3.2 of the.2010 edition); c) Changed the terms and definitions of “reference level range”, “reference input signal level”, “level linearity error” and “level range controller” (see 3.20, 3.21, 3.22, 3.24, 3.18, 3.19, 3.22, 3.24 of the.2010 edition); d) The temperature and relative humidity in the reference environmental conditions have been changed (see Chapter 4, 4.13 of the.2010 edition); e) Changed the acceptance limit of filter effective bandwidth deviation (see 5.12, 4.5 of the.2010 edition); f) The linear operating range of the filter has been changed (see 5.13, 4.6 of the.2010 edition); g) Deleted the contents of "real-time operation" and "flat frequency response" (see 4.7 and 4.10 of the.2010 edition); h) Added the contents of “time-invariant operation”, “overload indicator” and “filter decay time” (see 5.14, 5.17 and 5.18); i) Changed the filter air temperature range, the temperature and relative humidity of the controllable working environment area (see 5.22.2,.2010 edition) 4.14.2). This document is equivalent to IEC 61260-1.2014 "Electroacoustic octave and fractional octave filters Part 1.Specification". Please note that some of the contents of this document may involve patents. The issuing organization of this document does not assume the responsibility for identifying patents. This document was proposed by the Ministry of Industry and Information Technology of the People's Republic of China. This document is under the jurisdiction of the National Electroacoustics Standardization Technical Committee (SAC/TC23). This document was drafted by. Hangzhou Aihua Instrument Co., Ltd., Hunan Shengyi Measurement and Control Technology Co., Ltd., China Institute of Metrology, Nanjing University, Institute of Acoustics, Chinese Academy of Sciences, Third Research Institute of China Electronics Technology Group Corporation, Shenzhen Tiansuo Metrology and Testing Co., Ltd. The State-owned No. 4380 Factory Jiaxing Branch, China Performing Arts Equipment Technology Association, Zhejiang Institute of Metrology, Beijing Ecological Environment Monitoring center. The main drafters of this document are. Zhang Shaodong, Liu Xiangheng, Bai Ying, Shen Yong, Li Xiaodong, Wu Xin, Cui Jian, Zhang Guoqing, Shu Guohua, Zhou Jianhui, Qiu Jianmin, Tan Jiateng, Niu Feng, Yuan Fang, He Yanjun. The previous versions of this document and the documents it replaces are as follows. ---First published as GB/T 3241-1982 in 1982, first revised in.1998, second revised in.2010; --- This is the third revision, GB/T 3241-2010 is divided into 3 parts, the standard number of this part isIntroductionA filter is a device that separates the components of a signal by frequency, and octave and fractional octave filters are devices that have a single A bandpass filter with a transmission band and an upper cutoff frequency and a lower cutoff frequency ratio equal to an octave frequency ratio or a certain power thereof. Octave and fractional Octave filters are usually used in conjunction with sound measuring instruments such as sound level meters for spectral analysis of sound signals. GB/T 3241 aims to specify the performance requirements for octave and fractional octave filters and to describe the type evaluation tests and periodic tests. The method is planned to consist of three parts. --- Part 1.Specification. The purpose is to specify the performance requirements for octave and fractional octave filters. --- Part 2.Type evaluation test. The purpose is to ensure that all testing laboratories use a consistent method to perform octave and fractional Type evaluation test of octave band filters. --- Part 3.Periodic test. The purpose is to ensure that all testing laboratories or metrology laboratories perform octave testing in a consistent manner. and periodic experiments with fractional-octave filters. To evaluate compliance with performance specifications, this document uses different criteria from GB/T 3241-2010. GB/T 3241-2010 does not provide any requirements or recommendations for considering measurement uncertainty in the evaluation of conformity to performance specifications. Due to the lack of requirements or recommendations on measurement uncertainty, when the measured deviation from the design target is close to the limit of the allowable deviation, The determination of compliance with the specification becomes ambiguous. If compliance is determined based on whether the measured deviation exceeds the limit, then the octave and The end user of the fractional-octave band filter will be subject to the risk that the actual deviation from the design target exceeds the limit. To eliminate ambiguity, the 29th Technical Committee of the International Electrotechnical Commission (IEC) determined at its.1996 meeting that in formulating standards, Measurement uncertainty should be taken into account when evaluating the performance of the system. This document adopts the modified criteria for compliance with the specification. Compliance is confirmed when the following conditions are met simultaneously. a) the measured deviation from the design target does not exceed the applicable acceptance limit; b) The measurement uncertainty does not exceed the corresponding maximum permissible uncertainty. The acceptance limits are similar to the design and manufacturing tolerance limits in GB/T 3241-2010. The actual measurement uncertainty and the maximum allowable measurement uncertainty are determined based on a coverage probability of 95%, unless there is more specific information. Otherwise, the acceptance limits and maximum allowable uncertainties specified in this document can be used to evaluate specific octave or fractional octave filters. or the contribution of the filter bank to the total measurement uncertainty. Electroacoustic Octave and Fractional Octave Filters Part 1.Specification1 Scope1.1 This document specifies the performance requirements for bandpass filters implemented using analog, sampled data, and digital methods. There are filters whose relative attenuation characteristics have a passband region that is a constant percentage of the exact center frequency. The instrument may contain any number of adjacent bandpass filters covering any desired frequency range. 1.2 This document gives the performance requirements for two filter grades, Class 1 and Class 2.In general, the specifications for Class 1 and Class 2 filters have similar characteristics. The main differences are the acceptance limits and the operating temperature range. The acceptance limits of Class 2 are greater than or equal to the acceptance limits of Class 1. The maximum permissible expanded measurement uncertainty is determined. 1.3 The design performance requirements given are based on octave ratios and center frequencies to the base 10. 1.4 Bandpass filters meeting the performance requirements of this document may be part of various measurement systems or a component such as a spectrum analyser. A component part of a specific instrument. 1.5 This document specifies the range of environmental conditions under which filters may be operated. The required range depends on whether the instrument incorporating the filter is designed to operate in an environment that is Controlled environmental conditions or more general on-site work. 1.6 Bandpass filters meeting the requirements of this document are suitable for various signals, such as time-varying, intermittent or steady-state, broadband or discrete frequency. It can provide frequency band filtered spectral information for signals of long or short duration.2 Normative referencesThe contents of the following documents constitute essential clauses of this document through normative references in this document. For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to This document. GB/T 9254.1-2021 Electromagnetic compatibility of information technology equipment, multimedia equipment and receivers Part 1.Emission requirements (CISPR32.2015,MOD) Note. There is no technical difference between the content cited in GB/T 9254.1-2021 and the content cited in CISPR22.2008. GB/T 17626.3-2023 Electromagnetic compatibility test and measurement technology Part 3.Radio frequency electromagnetic field radiation immunity test (IEC 61000-4-3.2020,IDT) Note. There is no technical difference between the referenced content of GB/T 177626.3-2023 and the referenced content of IEC 61000-4-3.2006. GB/T 17799.1-2017 General standard for electromagnetic compatibility - Immunity for residential, commercial and light industrial environments (IEC 61000-6- 1.2005,MOD) Note. There is no technical difference between the referenced content of GB/T 17799.1-2017 and the referenced content of IEC 61000-6-1.2005. GB/T 17799.2-2023 General electromagnetic compatibility standards Part 2.Immunity standards for industrial environments (IEC 61000-6- 2.2016,MOD) Note. There is no technical difference between the referenced content of GB/T 17799.2-2023 and the referenced content of IEC 61000-6-2.2005. GB/T 17799.3-2023 General standard for electromagnetic compatibility Part 3.Emissions of equipment in residential environments (IEC 61000-6-3. 2020, IDT) Note. There is no technical difference between the referenced content of GB/T 17799.3-2023 and the referenced content of IEC 61000-6-3.2006. ISO /IEC Guide 98-3 Measurement uncertainty Part 3.Guide to the expression of uncertainty in measurement (GUM..1995) ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 3241.1-2025_English be delivered?Answer: Upon your order, we will start to translate GB/T 3241.1-2025_English as soon as possible, and keep you informed of the progress. The lead time is typically 1 ~ 3 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB/T 3241.1-2025_English with my colleagues?Answer: Yes. The purchased PDF of GB/T 3241.1-2025_English will be deemed to be sold to your employer/organization who actually pays for it, including your colleagues and your employer's intranet.Question 3: Does the price include tax/VAT?Answer: Yes. 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