BS-6288-8-1989 IEC-60094-8-1987.pdf

BRITISH STANDARD BS 6288-8: 1989 IEC 94-8:1987 Magnetic tape sound recording and reproducing systems Part 8: Specification for eight-track magnetic tape cartridge for commercial tape records and domestic use UDC 681.846.7 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 This British 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 28 February 1989 © BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference EEL/22 Draft for comment 79/33117 DC ISBN 0 580 17143 4 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/22, upon which the following bodies were represented: British Broadcasting Corporation British Kinematograph, Sound and Television Society Council for Educational Technology for the United Kingdom Electronic Engineering Association Independent Broadcasting Authority Independent Television Association Sound and Communication Industries Federation The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Association of Professional Recording Studios Audio Engineering Society British Tape Industry Association Royal Photographic Society Training and Educational Systems Testing Bureau Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 © BSI 12-1999i Contents Page Committees responsibleInside front cover National forewordii Section 1. General 1Scope1 2Definitions1 Section 2. Mechanical requirements for cartridges and for recording and reproducing equipment 3Tape speed1 4Tape winding1 5Position, utilization and dimensions of magnetic tracks1 6Mechanical specifications2 Section 3. Electrical requirements for recording and reproducing equipment 7Recorded tape flux characteristic2 8Reproducing characteristic2 9Tolerances on recording and reproducing characteristics2 Section 4. Magnetic tape 10Dimension3 11Sensing foil3 12Flammability3 13Identification of tape sides3 Figure 1 Dimensions of the cartridge4 Figure 2 Head and switch positioning6 Figure 3 True point checking fixture7 Figure 4 Position of tracks8 Table I Track allocation for two-channel sound9 Table II Track allocation for four-channel sound9 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 ii © BSI 12-1999 National foreword This Part of BS 6288 was prepared under the direction of the Electronic Equipment Standards Committee and is identical with IEC 94-8:1987 “Magnetic tape sound recording and reproducing systems” Part 8 “Eight-track magnetic tape cartridge for commercial tape records and domestic use”, published by the International Electrotechnical Commission (IEC). BS 6288 consists of the following Parts: Part 1: Specification for general conditions and requirements; Part 2: Specification for calibration tapes; Part 3: Methods of measuring the characteristics of recording and reproducing equipment for sound on magnetic tape; Part 4: Methods for measuring the mechanical characteristics of magnetic tape for analogue recording; Part 5: Specification for electrical magnetic tape properties1); Part 6: Specification for reel-to-reel systems; Part 7: Specification for cassettes for commercial tape records and domestic use; Part 8: Specification for eight-track magnetic tape cartridge for commercial tape records and domestic use; Part 9: Specification for magnetic tape cartridge for professional use1); Part 10: Specification for time and address codes1); Part 11: Guide to an address code for compact cassettes1). Terminology and conventions. The text of the International Standard has been 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 drawn especially to the following. In the figures, the comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. 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 and ii, pages 1 to 10, 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. 1) In preparation. Cross-references International StandardCorresponding British Standard IEC 94-1:1981BS 6288 Magnetic tape sound recording and reproducing systems Part 1:1982 Specification for general conditions and requirements (Identical) Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 © BSI 12-19991 Section 1. General 1 Scope This standard applies to magnetic tape sound recording with eight-track endless loop cartridges for both stereo and four-channel sound. 2 Definitions The following definitions apply for the purposes of this standard. 2.1 endless loop cartridge a device composed of a case containing a recorded or unrecorded magnetic tape in the form of a multiturn endless loop carried on a single hub. The tape is unwound from the inside turn of the loop and returned to the outside turn of the loop the device can be easily and rapidly inserted in a recorder or reproducer designed for the purpose without handling the magnetic tape 2.2 capstan the spindle or shaft, often the motor shaft itself, which drives the tape 2.3 pressure roller (pinch roller) an idler roller which holds the magnetic tape against the capstan NOTESometimes called “puck” in the USA. 2.4 capstan pressure pad a member that holds the tape against the capstan in order to obtain suitable driving action of the tape 2.5 magnetic head an electromagnetic transducer for converting electric signal variations into magnetic flux variations or the converse 2.6 external tape guide a mechanical forked arm used to position the tape in a fixed path across the magnetic head 2.7 internal tape supports the members within the case to maintain the tape within an appropriate path 2.8 switch head a device that is utilized to change the magnetic head position. In its simplest form, the switch head may consist of two electrical contacts that are shorted by a strip of conducting foil placed on the magnetic tape 2.9 pressure pad a resilient member used to hold the tape against a head Section 2. Mechanical requirements for cartridges and for recording and reproducing equipment 3 Tape speed The tape speed shall be 9.53 cm/s (3 3/4 in/s) ± 2 %. The speed and tolerance apply to machines operating from supplies having frequencies and voltages as specified by the manufacturer. 4 Tape winding The magnetic coating shall face the openings at the front of the cartridge. 5 Position, utilization and dimensions of magnetic tracks The designation of magnetic tracks is as follows: if the tape moves from left to right with the magnetic coating facing away from the observer, the top track is designated No. 1, the track immediately below it is designated No. 2 track, and so on. 5.1 Commercial tape records The track dimensions shall be in accordance with Figure 4, page 8. 5.1.1 Two-channel sound The track allocation shall be in accordance with Table I. All tracks shall be recorded for reproduction in the same direction. All areas adjacent to the recorded tracks specified in Figure 4, page 8, shall be free of recorded signals. 5.1.2 Four-channel sound The track allocation shall be in accordance with Table II. All tracks shall be recorded for reproduction in the same direction. All areas adjacent to the recorded tracks specified in Figure 4 shall be free of recorded signals. NOTEThe recommended reproducing head core width is 0.508 mm (0.020 in) with a centre-to-centre dimension of 3.23 mm (0.127 in) for two track heads and 1.61 mm (0.063 in) for four track heads. 5.2 Domestic use As for commercial tape records. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 2 © BSI 12-1999 5.3 Phasing of tracks Tracks containing correlated information shall be recorded with head gaps in line, and perpendicular to the direction of travel. In recording, phasing shall be such that in-phase signals shall produce in-phase magnetization of correlated tracks. In reproducing, in-phase magnetization of correlated tracks shall produce in-phase signals. 6 Mechanical specifications Constructional data which standardize the cartridge to secure interchangeability of cartridges on any tape recorder or player of different manufacture are given in Figure 1, Figure 2 and Figure 3, page 4, page 6 and page 7, which shall be interpreted in accordance with the following notes (to which reference is made in the figures): a) Operation of the cartridge depends to a large extent upon the design of the player. The cartridge shall be clamped in the reference position in order to maintain adequate contact between capstan, tape, and pressure roller or pad. Head penetration shall be sufficient to ensure good contact with the magnetic tape. It becomes necessary, therefore, to use cartridge reference base lines in designing the player. The cartridge dimensions are specified in accordance with this philosophy. b) Side dimensional base line Due to the spring action of the roller in the notch of the lower left side of the case, facing the end with openings, the cartridge is forced against the capstan and against a guide rail on the logical dimensional base line, designated B-B in Figure 1, page 4. c) Front dimensional base line The dimensional base line A-A is a perpendicular from the surface of a 6.35 mm (0.250 in) diameter reference capstan to the reference side of the cartridge B-B. The reference capstan is located relative to the reference side as being on the centreline G-G of the pressure roller with an engagement pressure of 13.4 N applied along the centreline. (See Figure 1). d) Internal tape supports A theoretical tape angle on the approach side of the magnetic head is specified in order to allow freedom of design with regard to location of the centre tape support. The 14 ± 2° angle is the theoretical tape angle formed by the centre point of the head and a tape support in the cartridge. (See Figure 2, page 6). e) Four shaded areas (/ / / / / / / /) define unobstructed openings in the cartridge for head and switch penetration (except for area covered by tape). (See Figure 1). f) Three shaded areas (: : : : : : : : : : :) define openings in the cartridge unobstructed by fixed members (for external tape guidance). (See Figure 1). g) The 2.41/1.40 mm (0.095/0.055 in) dimension applies only at the front surface of the cartridge designated as D½. (See Figure 1). h) The 0.64 mm (0.025 in) maximum dimension applies only at the front surfaces of the cartridge designated as D and D½. (See Figure 1). i) To check the location of notch reference point, it is recommended that the notch fixture in Figure 3, page 7, be used. j) Shaded areadefines the unobstructed opening for the capstan. (See Figure 1). k) Dimensions indicated for slot apply for 4 channel sound cartridge only. The slot is provided to permit the player to sense that the cartridge has been recorded for 4 channel sound. (See Figure 1). m) Pressure pad force should be 0.2 N (0.7 oz) nominally when head penetration is as specified in Figure 2. n) Width of cartridge of between 101.60 mm and 100.84 mm (4.00 in and 3.970 in) is obligatory within the area defined by 4.7 mm (0.185 in) and 17.4 mm (0.685 in) above dimensional base line C and from 16 mm to 88.9 mm (0.630 in to 3.50 in) above dimensional base line A. Section 3. Electrical requirements for recording and reproducing equipment 7 Recorded tape flux characteristic As in IEC Publication 94-1 for a tape speed of 9.53 cm/s (3 3/4 in/s). 8 Reproducing characteristic As in IEC Publication 94-1. 9 Tolerances on recording and reproducing characteristics As in IEC Publication 94-1. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 © BSI 12-19993 Section 4. Magnetic tape 10 Dimension The tape shall have a width of 6.30 mm. 11 Sensing foil The conductive sensing foil shall be placed on the oxide side of the tape to complete the circuit through the switching head. The foil shall cover a minimum of 5.6 mm (0.22 in) of the tape width and shall be not less than 9.53 mm (0.375 in) nor more than 22.9 mm (0.9 in) in length. NOTEThe minimum conductive sensing foil length indicated may result in insufficient mechanical strength if used as a splice. The electrical resistance of a length of 6.35 mm (0.25 in) of the sensing foil shall not exceed 0.1 7 12 Flammability As in IEC Publication 94-1. 13 Identification of tape sides Not applicable. 0 0.06 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 4 © BSI 12-1999 Figure 1 Dimensions of the cartridge Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 © BSI 12-19995 Explanation of Figure 1 Remarks: Notes from a) to n) are to be found in Clause 6. Dimensions are expressed in millimetres; those in brackets are expressed in inches. Where two numbers are mentioned, the upper one gives the maximum, the lower one the minimum dimension. The encircled numbers in the figure refer to the explanations given hereafter. 1. Supporting edges and ribs optional within 16.0 mm (0.630 in) of front. 2. True point. 3. Reference capstan. 4. Front corners. 5. Upper internal tape barrier (this location only). 6. Tape CL (Ref.). 7. Area for pressure pad rigid support. 8. Lower internal tape barrier (this location only). Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 6 © BSI 12-1999 Figure 2 Head and switch positioning Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6288-8:1989 © BSI 12-19997 Figure 3 True point checking fixture (see 2, Figure 1) Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 09:50:33 GMT+00:00 2006, Uncontrolled Copy,