1、BRITISH STANDARD BS 6840-6: 1987 IEC 268-6: 1971 Sound system equipment Part 6: Methods for specifying and measuring the characteristics of auxiliary passive elements IEC title: Sound system equipment. Part 6: Auxiliary passive elements UDC 621.396+681.84:621.395.61:621.317.6BS6840-6:1987 This Briti
2、sh Standard, having been prepared under the direction of the Electronic Equipment Standards Committee, was published under the authority of the Board of BSI and comes into effect on 30 November 1987 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference EEL
3、/32 Draft for comment 73/23761 DC ISBN 0 580 16223 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Electronic Equipment Standards Committee (EEL/-) to Technical Committee EEL/32, upon which the following bodies were represented: Associ
4、ation of British Theatre Technicians Association of Sound and Communications Engineers Limited Audio Engineering Society British Educational Equipment Association British Kinematograph, Sound and Television Society British Radio and Electronic Equipment Manufacturers Association British Telecommunic
5、ations plc Cable Television Association of Great Britain Consumer Standards Advisory Committee of BSI Consumers Association Federation of British Audio Independent Television Companies Association Institution of Electronic and Radio Engineers Radio Electrical and Television Retailers Association Roy
6、al Institute of British Architects Royal National Institute for the Deaf Society of Cable Television Engineers Training and Educational Systems Testing Bureau Amendments issued since publication Amd. No. Date of issue CommentsBS6840-6:1987 BSI 07-1999 i Contents Page Committees responsible Inside fr
7、ont cover National foreword iii 1 Scope 1 2 Object 1 Chapter I: Conditions for specification and measurement 3 General conditions 1 4 Rated conditions and normal working conditions 1 Chapter II: Characteristics to be specified and the relevant measuring methods Section 1. Auxiliary passive elements
8、5 Diagram 2 5.1 Structure diagram (block schematic) 2 6 Terminals and controls 2 6.1 Marking 2 6.2 Symbols for marking 2 7 Input characteristics 3 7.1 Rated source impedance 3 7.2 Input impedance 3 7.3 Rated source e.m.f. 4 8 Output characteristics 4 8.1 Rated load impedance 4 8.2 Output impedance 4
9、 9 Limiting characteristics 4 9.1 Overload source e.m.f. 4 9.2 Temperature limited input voltage 5 10 Attenuation 5 10.1 Rated matched insertion loss 5 10.2 Voltage attenuation (insertion attenuation) 5 11 Response 6 11.1 Frequency response 6 11.2 Effective frequency range 6 11.3 Phase-frequency res
10、ponse 6 12 Amplitude non-linearity 7 12.1 Harmonic distortion 7 12.2 Distortion curves 8 13 Unbalance 8 13.1 Unbalance of the input 8 13.2 Unbalance of the output 9 14 External influences 11 14.1 General 11 14.2 Rated equivalent source e.m.f. for external magnetic fields of power supply frequency 11
11、 14.3 Residual equivalent source e.m.f. for external magnetic fields of power supply frequency 11 15 Magnetic stray field 12 15.1 Magnetic stray field generated by the passive element 12 16 Alignment 12 16.1 Attenuation alignment 12BS6840-6:1987 ii BSI 07-1999 Page 16.2 Phase alignment 13 Section 2.
12、 Widely used passive elements 17 Attenuators 13 17.1 Residual attenuation 13 17.2 Attenuation range 13 17.3 Attenuation steps 14 17.4 Ultimate attenuation 14 18 Transformers 14 18.1 Impedance ratio 14 18.2 Voltage ratio 14 18.3 Rated output power 14 18.4 Limiting direct current 15 19 Filters and equ
13、alizers 15 19.1 Reference frequency response 15 19.2 Tone control range 15 Section 3. Physical characteristics and cable assemblies 20 Dimensions 15 21 Weight 15 22 Cable assemblies 15 Section 4. Classification of the characteristics to be specified 23 General 15 24 Classification 16 Appendix A 18 F
14、igure 1 Input impedance, balanced input, free from earth 18 Figure 2 Input impedance, balanced input, free from earth 18 Figure 3 Input impedance, balanced input, connected to earth 19 Figure 4 Input impedance, balanced input, connected to earth 19 Figure 5 Input impedance, unbalanced input 19 Figur
15、e 6 Input impedance, unbalanced input 20 Figure 7 Unbalance of the input 20 Figure 8a Unbalance of the internal impedance 21 Figure 8b Unbalance of the output e.m.f. 21 Figure 8c Internal impedance of the source of unbalance 22 Figure 9 Arrangement of three coils for the production of a uniform alte
16、rnating magnetic field 23 Figure 10 Search coil for measuring the magnetic field strength 24 Publications referred to Inside back coverBS6840-6:1987 BSI 07-1999 iii National foreword This British Standard has been prepared under the direction of the Electronic Equipment Standards Committee and is id
17、entical with Publication268.6:1973 “Sound system equipment” Part 6 “Auxiliary passive elements” published by the International Electrotechnical Commission (IEC). The text of this Part of BS6840 is unchanged from the text of BS5428-4:1978 which is now withdrawn. All Parts and Sections of BS5428 will
18、be published as Parts of BS6840 in order to achieve consistency of numbering between the corresponding Parts of the IEC Publication and the British Standard. BS6840 consists of the following parts: Part 1: Methods for specifying and measuring general characteristics used for equipment performance (S
19、upersedes part of BS5428-1); Part 2: Specification for general terms and calculation methods (Supersedes part of BS5428-1) 1) ; Part 3: Methods for specifying and measuring the characteristics of sound system amplifiers (Supersedes BS5428-2) 1) ; Part 4: Methods for specifying and measuring the char
20、acteristics of microphones (Previously BS5428-3); Part 5: Methods for specifying and measuring the characteristics of loudspeakers (Supersedes BS5428-11 and BS 5428-11: Supplement 1) 1) ; Part 6: Methods for specifying and measuring the characteristics of auxiliary passive elements (Previously BS542
21、8-4); Part 7: Methods for specifying and measuring the characteristics of headphones and headsets (New) 1) ; Part 8: Methods for specifying and measuring the characteristics of automatic gain control devices (Previously BS5428-7); Part 9: Methods for specifying and measuring the characteristics of a
22、rtificial reverberation, time delay and frequency shift equipment (Previously BS5428-8); Part 10: Specification for programme level meters (Supersedes BS5428-9); Part 11: Specification for application of connectors for the interconnection of sound system components (Supersedes BS5428-5.2) 1) ; Part
23、12: Specification for application of connectors for broadcast and similar use (Supersedes BS5428-5.3) 1) ; Part 13: Guide for listening tests on loudspeakers (New); Part 14: Guide for circular and elliptical loudspeakers: outer frame diameters and mounting dimensions (Previously BS5428-5.1); Part 15
24、: Specification for matching values for the interconnection of sound system components (Supersedes BS5428-10) 1) ; Part 16: Guide to the RASTI method for the objective rating of speech intelligibility in auditoria (New) 1) . Terminology and conventions. The text of the international standard has bee
25、n approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards: attention is especially drawn to the following. Wherever the word “Publication” or “Recommendation” appears, referring to t
26、his standard, it should be read as “British Standard”. References to page numbers in the text relate to the IEC page numbers given in brackets at the bottom of each page. 1) In preparation.BS6840-6:1987 iv BSI 07-1999 The Technical Committee has reviewed the provisions of IEC27, to which reference i
27、s made in 6.2 and IEC 65, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this British Standard. A related British Standard to IEC27 is the series of Parts of BS5775 which are themselves identical to the ISO31 series of Parts. A related Br
28、itish Standard to IEC65:1976 is BS415:1979. 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 obligation
29、s. Cross-references International standard Corresponding British Standard IEC 68 BS 2011 Basic environmental testing procedures (Mostseparately published Parts are identical) IEC 94 BS 6288 Magnetic tape sound recording and reproducing systems (Separately published Parts are identical) IEC 98 BS 485
30、2 Methods of defining and measuring the characteristics of disk record playing equipment IEC 268-1:1985 BS 6840 Sound system equipment Part 1:1987 Methods for specifying and measuring general characteristics used for equipment performance (Identical) BS 5428 Methods for specifying and measuring the
31、characteristics of sound system equipment IEC 268-2:1971 a Part 1:1977 General (Technically equivalent) IEC 268-3:1969 a Part 2:1979 Amplifiers (Technically equivalent) IEC 617:1983 b BS 3939 Guide for graphical symbols for electrical power, telecommunications and electronics diagrams (Separately pu
32、blished Parts are identical) a These Parts of BS5428 will be withdrawn when revision of IEC268-2 and IEC268-3 are published and implemented as Parts of BS6840. b IEC617:1983 supersedes IEC117. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to24, a
33、n 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.BS6840-6:1987 BSI 07-1999 1 1 Scope Auxiliary passive elements shall be understood to include su
34、ch elements as attenuators, transformers, filters and equalizers, applied as separate units to be combined with other separate sound system units to constitute a complete sound system. NOTE 1Auxiliary passive elements which are intended to be mounted as components in a sound system unit and to form
35、a non-interchangeable part of such a unit, are not within the scope of this Recommendation. Some characteristics are to be specified for all types of auxiliary passive elements. These are given in Chapter I and Section 1. Further characteristics to be specified for the different types of auxiliary p
36、assive elements are given in Section 2, Clauses 17, 18 and 19. NOTE 2Auxiliary elements may sometimes include electronic amplification, in which case these elements are considered as amplifiers and are dealt with in IEC Publication268-3, Sound System Equipment, Part3: Sound System Amplifiers. NOTE 3
37、If a network has more than four terminals as e.g. a cross-over network, it is nevertheless treated in this Recommendation as an assembly of four terminal networks. 2 Object This Publication gives recommendations relative to the characteristics to be specified and the relevant measuring methods for a
38、uxiliary passive elements for sound system equipment. In general, the methods of measurement recommended are those which are seen to be the most directly related to the definitions. This does not exclude the use of other methods which will give equivalent results. Chapter I: Conditions for specifica
39、tion and measurement 3 General conditions Reference is made to IEC Publication268-1, Sound System Equipment, Part 1: General, as concerns: units and system of measurement; frequencies of measurement; quantities to be specified and their accuracy; marking; ambient conditions; filters, networks, and m
40、easuring instruments for noise specification and measurement; individual specification and type specification; graphical presentation of data; scales for graphical presentation of data. 4 Rated conditions and normal working conditions 4.1 Introduction For convenience in specifying how auxiliary pass
41、ive elements are to be set up for measurement or verification, certain sets of conditions have been defined in this Recommendation under the respective titles of rated conditions and normal working conditions. Three ratings are basic to the formulation of these concepts: rated source impedance; rate
42、d source e.m.f.; rated load impedance. To obtain the correct conditions for measurements, the above-mentioned ratings shall be taken from the manufacturers specification. These ratings themselves are not subject to measurement but they constitute the basis for measuring the other characteristics. Th
43、e prefix “rated” applied to other characteristics relates to the specification or measurement of the particular characteristic under rated conditions or under conditions unambiguously connected with them. This applies to the following characteristics: rated matched insertion loss; rated equivalent s
44、ource e.m.f. for external magnetic field of power supply frequency. Concerning the position of the controls for rated conditions and normal working conditions, it must be taken into account that, when an auxiliary passive element is provided with a volume (attenuation) control and/or a tone control,
45、 the primary use of the element (variable attenuator, variable filter or equalizer) is generally to give a means of adjusting volume and frequency response in a sound system. Hence, all settings of the controls can be important. Some characteristics may be measured only for one specified setting of
46、the controls, particularly when they are influenced only slightly by the position of the controls themselves. This particular position of the controls may be taken as “reference setting”. In most cases, rated conditions and normal working conditions will include not only “reference setting” but also
47、 other settings of the controls, in order to supply more complete information. The values of the same characteristics, for different settings, will be presented either in a table or a graph.BS6840-6:1987 2 BSI 07-1999 4.2 Rated conditions An auxiliary passive element, considered as a four-terminal n
48、etwork with a specified pair of input terminals and a specified pair of output terminals, will be understood to be working under rated conditions when the following conditions have been fulfilled: source e.m.f. connected in series with the rated source impedance to the input terminals; output termin
49、als terminated with the rated load impedance; terminals not used terminated as specified; source e.m.f. adjusted to a sinusoidal voltage equal to the rated source e.m.f. at that frequency at which the output signal is the least influenced by the tone controls, if any. In the absence of a clear reason to the contrary, this frequency shall be the standard reference frequency of1000Hz (see IEC Publication268-1); volume control attenuation, if any, set to a specified position to giv
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