1、BRITISH STANDARD BS EN 61120-4:1993 IEC1120-4: 1992 Digital audio tape recorder reel-to-reel system, using6.3mm magnetic tape, for professional use Part4: Magnetic tape properties: definitions and methods of measurement The European Standard EN61120-4:1992 has the status of a BritishStandard UDC 621
2、.396.7:681.846.7.083.8:681.32:621.317.08/:620.1BSEN61120-4:1993 This BritishStandard, having been prepared under the directionof the Electronic Equipment Standards Policy Committee, was published underthe authority of the Standards Board and comesintoeffect on 15October1993 BSI 01-2000 The following
3、 BSI references relate to the work on this standard: Committee reference EEL/22 Draft for comment 91/32945 DC ISBN 0 580 22573 9 Cooperating organizations The European Committee for Electrotechnical Standardization(CENELEC), under whose supervision this European Standard was prepared, comprises the
4、national committees of the following countries: Austria Italy Belgium Luxembourg Denmark Netherlands Finland Norway France Portugal Germany Spain Greece Sweden Iceland Switzerland. Ireland United Kingdom Amendments issued since publication Amd. No. Date CommentsBSEN61120-4:1993 BSI 01-2000 i Content
5、s Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN61120-4 3 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back coverBSEN61120-4:1993 ii BSI 01-2000 National foreword This Br
6、itishStandard has been prepared under the direction of the Electronic Equipment Standards Policy Committee and is the English language version of EN61120-4:1992, Digital audio tape recorder reel-to-reel system, using6,3mm magnetic tape, for professional use Part4: Magnetic tape properties: definitio
7、ns and methods of measurement, published by the European Committee for Electrotechnical Standardization(CENELEC). It is identical with IEC1120-4:1992, published by the International Electrotechnical Commission(IEC). BS EN61120 consists of the following Parts. Part1: General requirements; Part2: Form
8、at A 1) ; Part3: Format B 1) ; Part4: Magnetic tape properties: definitions and methods of measurement; Part5: Reels for6,3mm digital audio tape 1) . A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correc
9、t 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 and ii, theEN title page, pages2 to10, an inside back cover and a back cover. This standard has been upd
10、ated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) In preparation.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN61120-4 August1992 UDC 621.396.7:681.846.7.083.8:681.32:621.317.08/:620.1 Descriptors: So
11、und recording, sound readers,magnetic tapes, measurements, properties English version Digital audio tape recorder reel-to-reel system, using6,3mm magnetic tape, for professional use Part4: Magnetic tape properties: definitions and methods of measurement (IEC1120-4:1992) Sytme denregistrement bande a
12、udionumrique, bobine bobine, utilisant une bande magntique de6,3mm, usage professionnel Partie4: Proprits des bandes magntiques: dfinitions et mthodes de mesure (CEI1120-4:1992) Digitales Tonbandgert Spulensystem mit Magnetband6,3mm fr Studioanwendung Teil4: Eigenschaften der Magnetbnder Begriffe un
13、d Meverfahren (IEC1120-4:1992) This European Standard was approved by CENELEC on1992-06-16. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-d
14、ate lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions(English, French, German). A version in any other language made by translation under
15、 the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Lu
16、xembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Bru
17、ssels 1992 Copyright reserved to CENELEC members Ref. No. EN61120-4:1992 EEN61120-4:1992 BSI 01-2000 2 Foreword The text of document60A(CO)139, as prepared by Sub-Committee60A: Sound recording, of IEC Technical Committee No. 60: Recording, was submitted to the IEC-CENELEC parallel vote in September1
18、991. The reference document was approved by CENELEC as EN61120-4 on16 June1992. The following dates were fixed: Annexes designated “normative” are part of the body of the standard. In this standard, Annex ZA is normative. Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Definitions 3 3.
19、1 Flux transitions 3 3.2 Physical recording density 3 3.3 Test density 3 3.4 Recording current wave-form 3 3.5 Recording current peak-to-peak value 4 3.6 Recommended recording current 4 3.7 Reference recording current 4 3.8 Test recording current 4 3.9 Average signal level 4 3.10 Standard reference
20、level 4 4 Technical requirements and test conditions 4 4.1 Standard atmospheric conditions 4 4.2 Mechanical characteristics of test equipment 5 4.3 Electrical characteristics of test equipment 5 4.4 Reference tapes 5 4.5 Condition of the tape to be tested 5 5 Electrical parameters to be measured 6 5
21、.1 Resolution 6 5.2 Overwrite characteristic 6 5.3 Drop-outs 6 Page 5.4 Relative average signal level to noise ratio 6 5.5 Characteristics of the sub-tracks in caseof bias-recording 6 6 Recommended parameters to be describedin published data for professional digitalaudiotapes 7 7 Mechanical paramete
22、rs to be measured 7 Annex A (informative) Name and address of themanufacturer of primary standard IEC reference tapes 10 Annex ZA (normative) Other international publications quoted in this standard with thereferences of the relevant European publications 10 Figure 1 Recording current wave-form 8 Fi
23、gure 2 Reference recording current and testrecording current 9 Figure 3 Average signal level to noise ratio 9 Table 1 Primary reference tape 5 Table 2 Recommended parameters 7 latest date of publication of an identical national standard (dop)1993-06-01 latest date of withdrawal ofconflicting nationa
24、l standards (dow)1993-06-01EN61120-4:1992 BSI 01-2000 3 1 Scope This part of IEC1120 applies to methods of measurement for the properties of magnetic tapes used in digital audio reel-to-reel recording and reproducing systems using6,3mm magnetic tape for professional use. 2 Normative references The f
25、ollowing standards contain provisions which, through reference in this text, constitute provisions of this part of IEC1120. At the time of publication of this standard, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of IEC1120 a
26、re encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC50(806):1975, International Electrotechnical Vocabulary(IEV) Chapter806: Recording and reproductio
27、n of sound and video. IEC94-4:1986, Magnetic tape sound recording and reproducing systems Part4: Mechanical magnetic tape properties. IEC94-5:1988, Magnetic tape sound recording and reproducing systems Part5: Electrical magnetic tape properties. IEC386:1972, Method of measurement of speed fluctuatio
28、ns in sound recording and reproducing equipment, Amendment No.1(1988). IEC1120-1:1991, Digital audio tape recorderreel-to-reel system, using6,3mm magnetic tape, for professional use Part1: General requirements. IEC1120-2:1991, Digital audio tape recorderreel-to-reel system, using6,3mm magnetic tape,
29、 for professional use Part2: Format A. IEC1120-3:1991, Digital audio tape recorderreel-to-reel system, using6,3mm magnetic tape, for professional use Part3: Format B. IEC1120-5:199x, Digital audio tape recorderreel-to-reel system, using6,3mm magnetic tape, for professional use Part5: Reels. 3 Defini
30、tions The following definitions apply for the purposes of this part. 3.1 flux transitions flux transitions are those parts along the tape where the magnetization reverses its direction 3.2 physical recording density physical recording density is the number of recorded flux transitions per unit lengt
31、h of track(flux transitions per millimetre) 3.3 test density for the purpose of testing the tape in accordance with this part the physical recording density shall be336 flux transitions per mm(test density A) and1008 flux transitions permm(test density B) with tolerances of 0,1% the corresponding no
32、minal squarewave frequencies F aand F bare32kHz and96kHz respectively at19,05cm/s, and64kHz and192kHz respectively at38,1cm/s 3.4 recording current wave-form the recording current to be used shall conform to the wave-form as given in Figure 1EN61120-4:1992 4 BSI 01-2000 3.5 recording current peak-to
33、-peak value recording current peak-to-peak values are specified as follows. I pp = Iw 1 + Iw 2 3.6 recommended recording current When the recording current is increased in amplitude from zero at test density B, the playback signal level(r.m.s. value) will increase to a maximum and then decrease. The
34、 smaller peak-to-peak value of the recording current which causes an output signal level equal to0,5dB of the maximum level is called the0,5dB below saturation current(seeFigure 2). The larger peak-to-peak value of the recording current which makes an output signal level equal to0,5dB of the maximum
35、 level is called the0,5dB above saturation current(see Figure 2). The recommended recording current shall be calculated from the value of0,5dB below saturation current and that of0,5dB above saturation current as follows: Recommended recording current is: I nr = I b +0,35 (I a I b ) 3.7 reference re
36、cording current reference recording current(peak-to-peak value) is the nominal recording current of the reference tape 3.8 test recording current the recording current to be used for testing the tape in accordance with this part shall have a peak-to-peak value equal to reference recording current 3.
37、9 average signal level average signal level is the average value of the r.m.s. output voltages over at least76mm along the tape, which has been recorded under the conditions of3.3 and using the test recording current for both density A and B 3.10 standard reference level defined as the average signa
38、l level(r.m.s. value) obtained by recording the reference tape, using the test recording current 4 Technical requirements and test conditions 4.1 Standard atmospheric conditions Ambient temperature:20 C 5 C Relative humidity:60% 15% Before commencing measurements, the test specimen shall have reache
39、d equilibrium with its environment. where Iw 1 is the actual current at t=and Iw 2 is the actual current at t=(seeFigure 1) where I nr is the recommended recording current I a =0,5dB above saturation current value I b =0,5dB below saturation current value T 1 2 - T 1 T 2 2 - +EN61120-4:1992 BSI 01-2
40、000 5 4.2 Mechanical characteristics of test equipment 4.2.1 Tape speed Tape transports shall be capable of operating at the rated speeds of19,05cm/s and38,1cm/s with a tolerance of 0,2%. The short term tape speed fluctuations shall be not more than0,1% when measured in accordance with IEC386 and it
41、s Amendment No.1, method2. 4.2.2 Tape width Tape transports shall be capable of accommodating and running the tapes of width6,3mm, conforming to tolerances specified in IEC1120-1. 4.2.3 Tape guides Tape guides shall ensure stability of measurement without affecting the inherent properties of the tap
42、e. 4.2.4 Tape to head force The tape to head force shall be such that maximum short wavelength output stability is obtained. 4.2.5 Tape wrap Tape wrap is defined as the total angular displacement of the tape by the head. The tape wrap shall be in accordance with the recommendation of the relevant he
43、ad manufacturer and shall be adjusted for maximum short wavelength response. 4.3 Electrical characteristics of test equipment 4.3.1 Electrical characteristics of test equipment shall be in accordance with IEC1120-1 4.3.2 Heads Heads authorized by the equipment manufacturers shall be used. 4.4 Refere
44、nce tapes Unrecorded magnetic tapes with specified properties intended to be used as a basis of comparison with other magnetic tapes or to measure the characteristics of tape recorders. 4.4.1 Reference tapes shall be provided on the basis of a primary standard issued from an agreed carefully measure
45、d batch of tape and shared among all member national standards organizations. Primary reference tapes shall be periodically revised to ensure they are compatible with currently available tape recorders of various categories covered by this part. 4.4.2 The measurements on these primary reference tape
46、s shall be certified by the issuing national standards organization and verified by a second IEC member national standards organization able and prepared to do so. Table 1 Primary reference tape 4.4.3 Secondary reference tape Unrecorded magnetic tape intended to be used for routine measurement purpo
47、ses, the properties of which are known and stated in relation to those of the primary reference tape. NOTESeeAnnex A for the name and address of the manufacturer of primary standard IEC reference tapes. 4.5 Condition of the tape to be tested The tape to be tested shall be erased. The residual signal
48、 level shall be50dB below the average signal level at a test density of bothA and B. Tape speed (cm/s) Tape width (mm) Reference batch number Use Country of origin Type Description 19,05 and 38,1 6,3 8000 Mandatory USA Format A and Format B CoFe 2 O 3 (oxide) NOTEFormat A and Format B are specified
49、in IEC1120-2 and IEC1120-3 respectively.EN61120-4:1992 6 BSI 01-2000 5 Electrical parameters to be measured 5.1 Resolution The resolution is the difference between the average signal level at test density B and that at test density A, when both are measured using the test recording current specified in3.8. 5.1.1 Relative resolution The relative resolution is expressed by D, where: D = d d o 5.2 Overwrite characteristic The overwrite characteristic is defined as the difference betw
