ISO 6068:1985

International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEXAYHAPOAHAR OPrAHM3ALWlfl i-l0 CTAH~APTM3ALWl.ORGANISATION INTERNATIONALE DE NORMALISATION
Information processing - Recording characteristics of
instrumentation magnetic tape (including telemetry
Systems) ‘- Interchange requirements
Caractkistiques d’enregistrement de Ia bande magnktique de mesure (y compris les systemes de
Traitemen t de l’informa tion -
telemesure) - Spkifica tions d’echanges
First edition - 1985-03-01
Ref. No. ISO 60684985 (EI
UDC 681327.64
tape recorders, specifications, magnetic properties, tests, magnetic
information interchange, magnetic tapes,
Descriptors : data processing,
tests, measuring instruments.
Price based on 98 pages
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of
national Standards bodies (ISO member bedies). The work of preparing International
Standards is normally carried out through ISO technical committees. Esch member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the ISO Council. They are approved in accordance With ISO procedures requiring at
least 75 % approval by the member bodies voting.
International Standard ISO 6068 was prepared by Technical Committee ISO/TC 97,
Information processing s ys tems.
lt cancels and replaces ISO 3413-1975 and ISO 3615-1976 of which it constitutes a
technical revision.
0 International Organkation for Standardkation, 1985
Printed in Switzerland
ii
Contents
Page
1 Scope and field of application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 References. 1
3 Definitions. 1
4 Tape and recorder/reproducer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 General. 4
......................................
4.2 Tape and reel characteristics
..............................................
4.2.1 Tape widths
4.2.2 Reels. 4
....................................................
4.3 Tapespeeds
..................................... 4
Standard tape Speeds.
4.3.1
......................................
4.3.2 Effective tape Speeds
.............................................
4.4 Track configurations
...............................
4.5 Recorder/reproducer characteristics
..............................................
4.51 Data scatter
......................................
Data azimuth (static)
4.5.2
....................................
Data azimuth (dynamic)
4.5.3
...................... 5
4.5.4 Individual track data azimuth differente
.................................................
4.5.5 Headtilt
....................................
4.5.6 Head interchangeability
.............................................
4.5.7 Head polarity
.....................................
4.5.8 Standard tensile forte
.............................................
4.6 Other characteristics
...................................................
5 Modes of recording
............................................
5.1 Direct recording (DR)
Bandwidths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.1
. . .
Ill
5.1.2 Bias .
5.1.3 Record Parameters .
5.1.4 Reproduce Parameters. .
5.1.5 Other System Parameters. .
5.2 Single-carrier frequency modulation recording .
5.2.1 Bandwidths .
Carrier deviations
5.2.2 .
Record characteristics
5.2.3 .
5.2.4 Other System Parameters. .
5.3 Recording without bias .
5.3.1 General .
5.3.2 Optimum record Ievel .
5.4 Predetection recording .
5.5 Timing Signal recording .
5.6 Tape Speed correction and flutter compensation .
5.6.1 Types of control Signal .
5.6.2 Amplitude-modulated Speed-control Signal .
..................... 12
5.6.3 Constant-amplitude Speed-control Signal
5.6.4 Track allocation .
Modulation Patterns 16
6 .
......... 16
6.1 Multiple-carrier FM recording (frequency-division multiplexing)
6.1.1 Proportional-bandwidth subcarrier channels .
6.1.2 Constant-bandwidth subcarrier channels .
6.1.3 Subcarrier channel spacing .
Tape Speed correction and flutter compensation . 16
6.1.4
Recording mode 16
6.1.5 .
6.1.6 Subcarrier tests .
6.1.7 Information for users .
6.2 PAM recording
..................................................
6.2.1 General .
6.2.2 Waveform structure
.......................................
6.2.3 Pulse and minor frame rate 17
.................................
6.2.4 Accuracy and stability .

Multiple and submultiple sampling . 17
6.2.5
6.2.6 Frequency modulation . 17
6.2.7 Premodulation filtering .
........................................ 18
6.2.8 PAM test methods
6.3 PCMrecording .
6.3.1 General .
6.3.2 Word and minor frame structure. . 18
PCM bit representations . 18
6.3.3
............................ 18
6.3.4 Minimum and maximum bit rates
..................................... 18
6.3.5 Accuracy and stability
6.3.6 Multiple and submultiple sampling .
6.3.7 Premodulation filtering (not applicable when waveforms are
.......................... 19
recorded directly on magnetic tape)
6.3.8 PCM record characteristics .
6.3.9 PCM System tests .
Annexes
A Recommended procedures for testing recorder/reproducer Systems . .
............ 76
B Magnetit tape recorder/reproducer information and use criteria
...... 79
C Additional notes for the testing of magnetic tape recorder/reproducers
........... 94
D PCM Standards - Additional information and recommendations
E Use criteria for frequency division multiplexing .

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INTERNATIONAL STANDARD ISO 60684985 (E)
Information processing - Recording characteristics of
instrumentation magnetic tape (including telemetry
Interchange requirements
Systems) -
3.1 bi-Phase (or Bi-@) : Form of representation for binary
1 Scope and field of application
“1” and “0” in pulse code modulation IPCM). Three variants,
known as “level”, “mark” and “space”, are defined in 6.3.3
This International Standard specifies the tape and
and figure 1.
recorder/ reproducer characteristics and modes of recording to
enable users of different Systems to interchange information
recorded on instrumentation magnetic tape.
3.2 data azimuthl) : Angle in the plane of the tape, at any
instant in time, between a line perpendicular to the reference
edge of the tape and either of the two parallel lines defining
Modulation Patterns are described in clause 6.
data scatter.
Test procedures recommended for use in measuring perfor-
NOTE - Data azimuth may be expressed as the sum of static and
mance Parameters of magnetic tape recorder and reproducer
dynamic components in the form :
Systems are described in annex B.
A + Bf(t)
where
Annexes C to F provide additional information but do not form
patt of this International Standard. The characteristics of
‘f(t) dt = 0
unrecorded tape are specified in ISO 6371. s
3.3 data azimuth (dynamicll) : Maximum angular devia-
tion, over a period of time, of the data azimuth from its mean
2 References
value as defined by data azimuth (static). For the purposes of
this definition, the word maximum is interpreted as being at the
95 % probability level. For a Gaussian distribution, this is two
ISO 1858, Information processing - Generalpurpose hubs and
Standard deviations (2 a).
reels, with 76 mm (3 in ) centre hole, for magnetic tape used in
in terchange ins trumen ta tion applica tions.
NOTE - Data azimuth (dynamic) is the maximum value of the quantity
BjIt) in the note on data azimuth.
ISO 1860, lnforma tion processing - Precision reels for
magnetic tape used in in terchange instrumen ta tion applica-
3.4 data azimuth (static)l) : Mean value, over a period of
tions.
time, of the data azimuth.
NOTE - Data azimuth (static) is the quantity A in the note on data
ISO 3802, Information processing - General purpose reels
azimuth.
with 8 mm (5116 in) centre hole for magnetic tape for in ter-
Change instrumen ta tion applica tions.
3.5 data scatterl) : Minimum distance between two parallel
I S 0 637 1, lnforma tion processing - In terchange prac tices and lines, in the plane of the tape, between which all data tran-
test methods for unrecorded instrumentation magnetic tape. sitions recorded in the same head, at the same time, shall fall.
3.6 data spacing : Distance on the tape between
simultaneous events recorded on odd and even numbered
3 Definitions tracks, when interlaced heads are used.
NOTE - On recording, this is equal to the head spacing, but on
The following terms have a special technical meaning in this
reproducing is only exactly equal to head spacing when record and
International Standard, and no attempt is made to lay down
reproduce tensions are equal. Different record and reproduce tensions
definitive terminologies outside the specific context of this
will give rise to small errors in time correlation between the Signals from
International Standard. the two heads.
1) The errors in location and angular relation among transient data recorded simultaneously on all odd or even tracks are defined by the terms : data
: head azimuth, gap scatter and
azimuth, data scatter, and individual track data azimuth differente. These are approximately equivalent to the terms
head Segment gap azimuth differente; however, guiding misalignment is included in the data location error definitions.

ISO 6068-1985 (El
3.19 head reference plane : The plane, which may be im-
pulse) : Percentage
37 duty factor tof a occupancy of
aginary (for some head designers, it is the nominal head moun-
pulse duration within a pu Ise period or time-slo t.
ting surface), parallel to the reference edge of the tape and
perpendicular to the plane of the tape (sec figure 3). (For the
purpose of the definition, the tape shall be considered as
3.8 edge margin (IM) : Distance between the outside edge
perfett. )
of the highest numbered track and the tape edge ( see figu re 5).
3.20 head Segment : Single transducer which reco rds or
3.9 edge margin, minimum UL&.,) : Minimum allowable
reproduces one track on magnetic tape (sec figure 3).
value of edge margin.
3.21 head Segment gap azimuth : The angle, in the plane
NOTE - This value places an additional constraint on track configura-
of the tape, between a line perpendicular to the head reference
tions since, in general, the simultaneous application of all worst case
plane and the gap trailing edge in a record head Segment (see
tolerantes for track width, track location and tape width will result in a
figure 3).
value of edge margin less than Ib&.,.
3.22 head Segment gap azimuth differente : Angular
deviation of the azimuth of head Segment gaps, in a head, from
3.10 frequency division multiplex (FDM) : Multiplexing
the head azimuth (see figure 3).
technique in which modulated subcarriers are combined in
such a way that each of a number of data channels occupies a
unique and defined section of the available bandwidth.
3.23 head Segment numbering : Numbering of a head
Segment shall correspond to the track number on the magnetic
tape on which that head Segment normally operates. Head 1 of
3.11 frame, major :
The minimum Overall repetitive se-
a pair will contain all odd-numbered Segments while head 2 will
quence of pulses, in which each input channel is sampled at
contain all even-numbered Segments (sec figures 3 and 4).
least once. The period of the major frame is determined by the
length of the longest submultiple frame(s).
3.24 head spacing (S) : The distance along the tape path
between the gap centre lines of head 1 and head 2, when in-
terlaced heads are used (sec figure 4).
3.12 frame, minor : A group of data pulses or samples; it
includes and ends with a synch. pulse or Pattern. The minor
3.25 head tilt : Angle, between the plane tangent to the
frame is an integral submultiple of the major frame and, in the
front (active) surface of the head at the centre-line of the head
absence of subcommutation, is repetitive and equal to the
Segment gaps, and a line perpendicular to the head reference
major frame.
plane (sec figure 3).
3.13 frame, submultiple :
A repetitive group of subcom-
3.26 heads in-line : For in-line reco rding, only one
mutated data pulses. Supercommutation within a submultiple
head and one reproduce head will be u sed.
frame is possible (sec figure
...