BS-6840-2-1993 IEC-60268-2-1987.pdf

BRITISH STANDARD BS 6840-2: 1993 IEC 268-2: 1987 (including Amendment No. 1 May 1991 to IEC 268-2:1987) Sound system equipment Part 2: Glossary of general terms and calculation methods (Implementation of CENELEC HD 483.2 S2) UDC 534.86:621.39:001.4 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 This British Standard, having been prepared under the direction of the Electronic Equipment Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 November 1993 © BSI 07-1999 First published August 1988 Second edition November 1993 The following BSI references relate to the work on this standard: Committee reference EEL/32 Draft for comment 84/28116 DC and DC 89/21657 DC ISBN 0 580 22345 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Power Electrical Engineering Standards Policy Committee (EEL/-) to Technical Committee EEL/32, upon which the following bodies were represented: Association of British Theatre Technicians Association of Electronics, Telecommunications and Business Equipment Industries Audio Engineering Society British Broadcasting Corporation British Educational Equipment Association British Kinematograph, Sound and Television Society British Radio and Electronic Equipment Manufacturers Association British Telecommunications plc Consumers Association Electronic Components Industry Federation Federation of British Audio Independent Television Association Institution of Electrical Engineers International Association of Broadcasting Manufacturers National Council for Educational Technology (NCET) Professional Lighting and Sound Association Radio Electrical and Television Retailers Association Royal Institute of British Architects Royal National Institute for Deaf People Society of Cable Television Engineers Sound and Communication Industries Federation Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 © BSI 07-1999i Contents Page Committees responsibleInside front cover National forewordii Foreword2 1General terms3 1.1Sound system3 1.2Compatibility3 1.3Variable consumption apparatus3 1.4Noise signal3 1.5Rated values3 2Power4 2.1Relative power level4 2.2Power level4 2.3Available power from the source4 2.4Available power gain4 3Voltage4 3.1Relative voltage level4 3.2Voltage level4 3.3Voltage gain5 3.4E.M.F. gain (overall voltage gain)5 4Source e.m.f.5 4.1Equivalent source e.m.f5 5Balance5 5.1Balanced circuits5 5.2Balanced inputs5 5.3Balanced outputs5 6Noise6 6.1Noise voltage6 6.2Signal-to-noise ratio6 6.3Equivalent noise source e.m.f.6 7Amplitude non-linearity6 7.1Introduction6 7.2Explanation of terms6 7.3Elucidation7 8Cross-talk and separation in multi-channel equipment8 8.1General8 8.2Cross-talk attenuation (from A to B)8 8.3Separation (of A from B)8 9Acoustic characteristics8 9.1Sound pressure level8 9.2Sound power level8 9.3Equivalent input sound pressure of a microphone8 10Polarity8 10.1 Characteristics to be specified9 10.2 Method of measurement9 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications13 National annex NA (informative) Cross-referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 ii © BSI 07-1999 Page Figure 1 Balance of the input9 Figure 2 Balance of the output10 Figure 3 Distortion spectra11 Figure 3a Harmonic distortion11 Figure 3b Modulation distortion11 Figure 3c Difference-frequency distortion12 Figure 3d Total difference-frequency distortion12 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 © BSI 07-1999iii National foreword This Part of BS 6840 has been prepared under the direction of the Electronic Equipment Standards Policy Committee. It is identical with IEC 268-2:1987 Sound system equipment Part 2: Explanation of general terms and calculation methods, as amended by Amendment No. 1 (May 1991), published by the International Electrotechnical Commission (IEC). This British Standard implements Harmonization Document HD 483.2 S2:1993, published by the European Committee for Electrotechnical Standardization (CENELEC). This British Standard supersedes BS 6840-2:1988 which is withdrawn. This edition introduces technical changes to bring this standard up-to-date but does not reflect a full review of the standard, which will be undertaken in due course. The changes introduced by the IEC Amendment No. 1 are indicated by a sideline in the margin. BS 6840 consists of the following Parts: Part 1: Methods for specifying and measuring general characteristics used for equipment performance; Part 2: Glossary of general terms and calculation methods; Part 3: Methods for specifying and measuring the characteristics of sound system amplifiers; Part 4: Methods for specifying and measuring the characteristics of microphones; Part 5: Methods for specifying and measuring the characteristics of loudspeakers; Part 6: Methods for specifying and measuring the characteristics of auxiliary passive elements; Part 7: Methods for specifying and measuring the characteristics of headphones and earphones1); Part 8: Methods for specifying and measuring the characteristics of automatic gain control devices; Part 9: Methods for specifying and measuring the characteristics of artificial reverberation time delay and frequency shift equipment; Part 10: Methods for specifying and measuring the characteristics of peak programme level meters; Part 11: Specification for application of connectors for the interconnection of sound system components; Part 12: Specification for applications of connectors for broadcast and similar use; Part 13: Guide for listening tests on loudspeakers; Part 14: Guide for circular and elliptical loudspeakers; outer frame diameters and mounting dimensions; Part 15: Specification for matching values for the interconnection of sound system components; Part 16: Guide to the “RASTI” method for the objective rating of speech intelligibility in auditoria; Part 17: Methods for specifying and measuring the characteristics of standard volume indicators. 1) In preparation. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 iv © BSI 07-1999 Additional information Scope. IEC 268-2 does not give the scope of the standard, which for the purposes of this British Standard is as follows: “This Part of BS 6840 specifies general terms and calculation methods for sound system equipment”. References to page numbers in the text relate to the IEC page numbers given in brackets at the bottom of each page. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, the HD title page, pages 2 to 14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI HARMONIZATION DOCUMENT DOCUMENT DHARMONISATION HARMONISIERUNGSDOKUMENT HD 483.2 S2 February 1993 UDC 534.86:621.39:001.4 Descriptors: Sound system equipment, definition, general, calculation methods English version Sound system equipment Part 2: Explanation of general terms and calculation methods (IEC 268-2:1987 + A1:1991) Equipements pour systèmes électroacoustiques Deuxième partie: Explication des termes généraux et méthodes de calcul (CEI 268-2:1987 + A1:1991) Elektroakustische Geräte Teil 2: Allgemeine Begriffe und Berechnungsverfahren (IEC 268-2:1987 + A1:1991) This Harmonization Document was approved by CENELEC on 1992-12-09. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for implementation of this Harmonization Document on a national level. Up-to-date lists and bibliographical references concerning national implementation may be obtained on application to the Central Secretariat or to any CENELEC member. This Harmonization Document exists in three official versions (English, French, German). CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels © 1993 Copyright reserved to CENELEC members Ref. No. HD 483.2 S2:1993 E Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 © BSI 07-1999 2 Foreword The CENELEC questionnaire procedure, performed for finding out whether or not the International Standard IEC 268-2:1987 and its amendment 1:1991 could be accepted without textual changes, has shown that no common modifications were necessary for the acceptance as Harmonization Document. The reference document was submitted to the CENELEC members for formal vote and was approved by CENELEC as HD 483.2 S2 on 9 December 1992. The following dates were fixed: Annexes designated “normative” are part of the body of the standard. In this standard, Annex ZA is normative. latest date of announcement of the HD at national level(doa) 1993-06-01 latest date of publication of a harmonized national standard(dop) 1993-12-01 latest date of withdrawal of conflicting national standards(dow) 1993-12-01 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 © BSI 07-19993 For the purpose of this standard, the following explanations of general terms and calculation methods apply: 1 General terms 1.1 Sound system An assembly of equipment which in combination enables sound signals or audio-frequency signals to be processed or transmitted. Such equipment may be, for example, transducers, amplifiers, recorders, etc. 1.2 Compatibility A component of a system is said to be compatible with another component if, when they are connected together, satisfactory operation is obtained. 1.3 Variable consumption apparatus An apparatus in which the power drawn from the supply system may vary significantly during operation, as a function of the signal or the load impedance or of the control settings (excluding power supply switches). NOTEFor some purposes, changes of less than 15 % may be insignificant. 1.4 Noise signal A stationary random signal having normal probability distribution of instantaneous values. Unless otherwise stated, the mean value is zero. NOTEThis explanation applies to noise signals used for testing. Noise as an unwanted signal is considered in Clause 6. 1.4.1 White noise signal A noise signal whose energy per unit bandwidthis independent of frequency. 1.4.2 Pink noise signal A noise signal whose energy per unit bandwidthis inversely proportional to frequency. 1.4.3 Broadband noise signal A noise signal, band-limited by means of a filter with defined amplitude/frequency response whose bandwidth is greater than that of the equipment under test. NOTEA broadband noise signal may be a band-limited white or pink noise signal, or have some other defined power spectrum. 1.4.4 Narrowband noise signal A noise signal, band-limited by means of a filter with defined amplitude/frequency response, whose bandwidth is small compared with that of the equipment under test. 1.5 Rated values In this standard, the term “rated value” is used in a particular sense. Wherever it is used it means “the value stated by the manufacturer”. The word “rated” has this meaning even though it is used in terms such as “rated conditions” or in the name of a characteristic. 1.5.1 Rated conditions When an equipment is to be used or tested it has to be operated under certain conditions which are fixed by the manufacturer. These conditions include electrical, mechanical and climatic conditions, and they cannot, by their nature, be verified by measurement. Rated conditions for a particular type of equipment generally include some or all of the following: Electrical Rated power supply voltage(s) Rated power supply frequency Rated source impedance(s) Rated source e.m.f.(s) Rated load impedance(s) Mechanical Mounting position Ventilation Climatic Rated ambient temperature ranges for operation and for full performance to specification Rated relative humidity range Rated air pressure range NOTERanges are defined by the extreme values, each of which may be regarded as a separate rated condition. 1.5.2 Rated value of a characteristic In IEC Publication 268, methods of measurement are given for a large number of characteristics. For each of these characteristics the manufacturer is required or permitted to state a value in the specification of equipment. This stated value is, by definition, the rated value of that characteristic (see Sub-clause 1.5). The use of the term “rated” in this sense is not restricted to a limited set of major characteristics but may be applied to any characteristic for which a method of measurement is given. Since the rated value is the value stated by the manufacturer, the defining title of the “characteristic to be specified” does not, in general, include the word “rated”; the rated value is not something which is measured but is decided by the manufacturer taking into account measurements on many samples of the equipment and theoretical tolerance calculations. %W % f - - %W % f - - Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:12:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6840-2:1993 4 © BSI 07-1999 For example, a method of measurement is described in IEC Publication 268-3 for the distortion-limited output power of an amplifier. The rated distortion-limited output power is the value stated by the manufacturer, usually calculated from measurements (according to the standard method) on several samples of the amplifier, supplemented by tolerance calculation. NOTEApplies to French text only. 1.5.3 Interdependent characteristics It often happens that the value of one characteristic is required to be stated for a particu