IEC 62742 Ed. 1.0

Electrical and electronic installations in ships - Electromagnetic compatibility (EMC) - Ships with a non-metallic hull

Provides fundamental definitions for general use in time domain pulse technology. It defines terms for pulse phenomena and characteristics which are prerequisite for efficient communication of technical information. It also defines terms for standards for methods of pulse characteristics measurement, for pulse apparatus, and for apparatus which employ pulse techniques.

Installations électriques et électroniques à bord des navires - Compatibilité électromagnétique - Navires ayant une coque non métallique

Donne les définitions fondamentales d'usage général dans la technologie des impulsions dans le temps. Elle définit les termes relatifs aux phénomènes impulsionnels et aux caractéristiques des impulsions qui sont a priori nécessaires pour assurer une communication efficace des informations techniques et rédiger les normes relatives aux méthodes de mesure des caractéristiques des impulsions, aux appareils à impulsions et aux appareils qui utilisent la technique des impulsions.

Impulzna tehnika in naprave – 1. del: Izrazi in definicije impulzov

General Information

• Status: Published
• Publication Date: 10-May-2021
• ICS: 01.040.17 - Metrology and measurement. Physical phenomena (Vocabularies)
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• Technical Committee: TC 18 - Electrical installations of ships and of mobile and fixed offshore units
• Current Stage: ACDV - Draft approved for Committee Draft with Vote
• Start Date: 27-Jan-2017
• Ref Project: SIST IEC 60469-1:2005 - Pulse techniques and apparatus. Part 1: Pulse terms and definitions

Standards Content (sample)

SLOVENSKI SIST IEC 60469-1:2005
STANDARD
junij 2005
Impulzna tehnika in naprave – 1. del: Izrazi in definicije impulzov
Pulse techniques and apparatus – Part 1: Pulse terms and definitions
ICS 01.040.17; 17.080 Referenčna številka
SIST IEC 60469-1:2005(en)

© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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NORME
CEI
INTERNATIONALE IEC
60469-1
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
1987-12
Techniques des impulsions et
appareils
Première partie:
Termes et définitions concernant les impulsions
Pulse techniques and apparatus
Part 1:
Pulse terms and definitions
© IEC 1987 Droits de reproduction réservés — Copyright - all rights reserved

Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in

utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,

procédé, électronique ou mécanique, y compris la photo- including photocopying and microfilm, without permission in

copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.

International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http: //www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
PRICE CODE
International Electrotechnical Commission
IEC MemnyHapomian 3nenrporexHwiecnan HoMHccein
Pour prix, voir catalogue en vigueur
• • For price, see current catalogue
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469-1 © I E C 1987 - 3 -
CONTENTS
Page
FOREWORD 5
PREFACE 5
Clause
1. General 7
1.1 Scope 7
1.2 Object 7
2. General terms 7
2.1
Co-ordinate system 7
2.2 Wave, pulse and transition 7
2.3 Waveform, epoch and feature 9
2.4
Qualitative adjectives 9
2.5
Quantitative adjectives 11
2.6 Time-related definitions 17
2.7 Reference lines and points 17
2.8 Miscellaneous 19
3. The single pulse waveform 21
3.1
Major pulse waveform features 21
3.2 Magnitude characteristics and references 21
3.3 Time characteristics and references 23
3.4 Other pulse waveform features 25
The single transition waveform 25
4.1 Step 25
4.2 Ramp 25
5. Complex waveforms 27
5.1 Combinations of pulses and transitions 27
5.2 Waveforms produced by magnitude superposition 27
5.3 Waveforms produced by continuous time superposition of simpler waveforms 27

5.4 Waveforms produced by non-continuous time superposition of simpler waveforms 29

5.5 Waveforms produced by operations on waveforms 31
6. Time relationships between different pulse waveforms 31
7. Distortion, jitter and fluctuation 33
7.1 Distortion 33
7.2 Qualitative distortion terms 33
7.3 Jitter and fluctuation 35
8. Miscellaneous pulse terms 35
8.1 Operations on a pulse 35
8.2 Operations by a pulse 37
8.3 Operations involving the interaction of pulses 39
8.4 Logical operations with pulses 39
FIGURES 40
INDEX 47
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469-1 © I E C 1987 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
PULSE TECHNIQUES AND APPARATUS
Part 1: Pulse terms and definitions
FOREWORD

The formal decisions or agreements of the I E C on technical matters, prepared by Technical Committees on which all

the National Committees having a special interest therein are represented, express, as nearly as possible, an international

consensus of opinion on the subjects dealt with.

2) They have the form of recommendations for international use and they are accepted by the National Committees in that

sense.

In order to promote international unification, the I E C expresses the wish that all National Committees should adopt

the text of the I E C recommendation for their national rules in so far as national conditions will permit. Any divergence

between the I E C recommendations and the corresponding national rules should, as far as possible, be clearly indicated

in the latter.
PREFACE

This standard has been prepared by Sub-Committee 66A: Generators, of I E C Technical Com-

mittee No. 66: Measuring Equipment for Electronic Techniques.

The text of this standard which replaces the first edition is based upon the following documents:

Six Months' Rule Report on Voting
66A(CO)38
66A(CO)36

Full information on the voting for the approval of this standard can be found in the Voting

Report indicated in the above table.
The following I E C publications are quoted in this standard:

Publications Nos. 351 (1976): Expression of the Properties of Cathode-ray Oscilloscopes.

469-2 (1987): Pulse Techniques and Apparatus,
Part 2: Pulse Measurement and Analysis, General Considerations.
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469-1 © I E C 1987 — 7
PULSE TECHNIQUES AND APPARATUS
Part 1: Pulse terms and definitions
1. General
1.1 Scope

This standard provides fundamental definitions for general use in time domain pulse

technology. It defines terms for pulse phenomena and pulse characteristics which are prerequi-

site to:
– efficient communication of technical information;
– standards for methods of pulse characteristic measurement;
standards for pulse apparatus;
– standards for apparatus which employ pulse techniques.
1.2 Object

Within its scope, the object of this standard is the definition of an internally consistent,

mathematically rigorous and general set of pulse terms which are applicable:
– to hypothetical and practical pulses;
– regardless of the applicable limits of error;
– to a wide range of technologies and disciplines;

– in a measurement situation, regardless of the means of measurement or the means for

waveform evaluation employed.
2. General terms
2.1 Co-ordinate system

Throughout the following, a rectangular Cartesian co-ordinate system is assumed in which,

unless otherwise specified:

– is the independent variable taken along the horizontal axis, increasing in the positive

time (t)
sense from left to right;

– magnitude (m) is the dependent variable taken along the vertical axis, increasing in the

positive sense or polarity from bottom to top;
the following additional symbols are used:
e = base of natural logarithms;

a, b, c, etc. = real parameters which, unless otherwise specified, may have any value

and either sign;
n =
a positive integer.
2.2 Wave, pulse and transition
2.2.1
Wave

A modification of the physical state of a medium which propagates in that medium as a

function of time* as a result of one or more disturbances.
* Terms in italic type are defined in this standard.
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469-1 © I E C 1987 — 9
2.2.2
Pulse

wave which departs from a first nominal state, attains a second nominal state and

ultimately returns to the first nominal state.
Throughout the remainder of this standard, "pulse" is included in "wave".
2.2.3 Transition

A portion of a wave or pulse between a first nominal state and a second nominal state.

Throughout the remainder of this standard, "transition" is included in "pulse" and "wave".

2.3 Waveform, epoch and feature
2.3.1 Waveform, pulse waveform, transition waveform

A manifestation or representation (e.g. graph, plot, oscilloscope presentation, equation(s),

table of co-ordinates or statistical data) or a visualization of a wave, pulse or transition.

Throughout the remainder of this standard:
— "pulse waveform" is included in "waveform;"
"transition waveform" is included in "pulse waveform" and "waveform."
2.3.2
Waveform epoch
The span of
time for which waveform data are known or knowable. A waveform epoch

manifested by equations may extend in time from – co to + o0 or, like all waveform

data, may

extend from a first datum time t o, to a second datum time t l (see Figure 1, page 40).

2.3.3 Waveform feature
A specified portion or segment of, or a specified event in, a waveform.
2.4
Qualitative adjectives

The adjectives in this sub-clause may be used individually or in combination, or in combi-

nation with adjectives in Sub-clause 2.5, to modify any substantive term in this standard.

2.4.1
Descriptive adjectives
2.4.1.1 Major (minor)

Having or pertaining to greater (lesser) importance, magnitude, time, extent, or the like, than

another similar feature(s).
2.4.1.2 Ideal

Of or pertaining to perfection in, or existing as a perfect exemplar of, a waveform or a

feature.
2.4.1.3
Reference
Of or pertaining to a
time, magnitude, waveform, feature or the like, which is used for

comparison with, or evaluation of, other times, magnitudes, waveforms, features or the like.

A reference entity may, or may not, be an ideal entity.
2.4.2 Time-related adjectives
2.4.2.1 Periodic (aperiodic)

Of or pertaining to a series of specified waveforms or features which repeat or recur regularly

(irregularly) in time.
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469-1
© I EC 1987 — 11 —
2.4.2.2 Coherent (incoherent)

Of or pertaining to two or more repetitive waveforms whose constituent features have (lack)

time correlation.
2.4.2.3
Synchronous (asynchronous)

Of or pertaining to two or more repetitive waveforms whose sequential constituent features

have (lack)
time correlation.
2.4.3
Magnitude-related adjectives
2.4.3.1 Proximal (distal)

Of or pertaining to a region near to (remote from) a first state or region of origin.

2.4.3.2 Mesial
Of or pertaining to the region between the
proximal and distal regions.
2.4.4
Polarity-related adjectives
2.4.4.1
Unipolar
Of, having or pertaining to a single polarity.
2.4.4.2
Bipolar
Of, having or pertaining to both polarities.
2.4.5
Geometrical adjectives
2.4.5.1 Trapezoidal
Having or approaching the shape of a trapezoid.
2.4.5.2
Rectangular
Having or approaching the shape of a rectangle.
2.4.5.3 Triangular
Having or approaching the shape of a triangle.
2.4.5.4 Sawtooth

Having or approaching the shape of a right-angled triangle (see Figure 2, page 41, wave-

form D).
2.4.5.5
Rounded
Having a curved shape characterized by a relatively gradual change in slope.
2.5 Quantitative adjectives

The adjectives in this sub-clause may be used individually or in combination, or in combi-

nation with adjectives in Sub-clause 2.4, to modify any substantive term in this standard.

2.5.1 Integer adjectives

The ordinal integers (i.e. first, second, ..., nth, last) or the cardinal integers (i.e. 1, 2, ...,

n) may be used as adjectives to identify or distinguish between similar or identical features.

The assignment of integer modifiers should be sequential as a function of time within a

waveform epoch
and/or within features thereof.
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469-1 © I EC 1987 13 —
2.5.2 Mathematical adjectives

All definitions in this sub-clause are stated in terms of time (the independent variable) and

magnitude (the dependent variable). Unless otherwise specified, the following terms apply only

to waveform data within a waveform epoch. These adjectives may also be used to describe the

relation(s) between other specified variable pairs (e.g. time and power, time and voltage).

2.5.2.1 Instantaneous
Pertaining to the magnitude at a specified time.
2.5.2.2 Positive (negative) peak
Pertaining to the maximum (minimum) magnitude.
2.5.2.3 Peak-to-peak

Pertaining to the absolute value of the algebraic difference between the positive peak

magnitude and the negative peak magnitude.
2.5.2.4 Root-mean-square (r.m.s.)
magnitude.
Pertaining to the square root of the average of the squares of the values of the
If the magnitude takes on discrete values, m., its root-mean-square value is:
mrms= [()
j=1
wherein the time intervals between adjacent values of m. are equal.
If the magnitude is a continuous function of time, m(t), its r.m.s. value is:
1 J m (t) dt lz
=[(

The summation or the integral extends over the interval of time for which the r.m.s.

magnitude is desired or, if the function is periodic, over any integral number of periodic

repetitions of the function.
2.5.2.5 Average

Pertaining to the mean of the values of the magnitude. If the magnitude takes on n discrete

values, m., its average value is:
(—)
j=1
wherein the time intervals between adjacent values of m. are equal.
If the magnitude is a continuous function of time, m(t), its average value is:
) [z m (td
m_ (
t2ti

The summation or the integral extends over the interval of time for which the average

magnitude is desired or, if the function is periodic, over any integral number of periodic

repetitions of the function.
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469-1 © I E C 1987 15 —
2.5.2.6 Average absolute

Pertaining to the mean of the absolute values of the magnitude. If the magnitude takes on

n discrete values, mj, its average absolute value is:
Fri-
\n/
wherein the time intervals between adjacent values of m are equal.

If the magnitude is a continuous function of time, m(t), its average absolute value is:

mt _ ^ 1 )
1 t m (t)dt
t 2 — t,
,lr

The summation or the integral extends over the interval of time for which the average

absolute magnitude is desired or, if the function is periodic, over any integral number of

periodic repetitions of the function.
2.5.2.7 Root sum of squares (r.s.s.)

Pertaining to the square root of the arithmetic sum of the squares of the values of the

magnitude. If the magnitude takes on n discrete values, m;, its root sum of squares value is:

mrss =
i=1
wherein the time intervals between adjacent values of m. are equal.

If the magnitude is a continuous function of time, m(t), its root sum of squares value is:

C m 2 (t) dt
m rss =
J 1

The summation or the integral extends over the interval of time for which the root sum of

squares magnitude is desired or, if the function is periodic, over any integral number of periodic

repetitions of the function.
2.5.3 Functional adjectives
2.5.3.1 Linear
Pertaining to a time
feature whose magnitude varies as a function of in accordance with the
following relation or its equivalent:
m=a
+bt
2.5.3.2 Exponential

Pertaining to a feature whose magnitude varies as a function of time in accordance with

either of the following relations or their equivalents:
-bt
m =ae
m= a(1— e-b`)
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— 17 —
469-1 © I E C 1987
2.5.3.3 Gaussian
time in
whose magnitude varies as a function of
Pertaining to a waveform or feature
accordance with the following relation or its equivalent:
b(t
m=ae- -`)Z where b>0
2.5.3.4 Trigonometric
varies as a function of time in
waveform or feature whose magnitude
Pertaining to a

accordance with a specified trigonometric function or by a specified relationship based on

trigonometric functions (e.g. cosine squared).
2.6 Time-related definitions
2.6.1 Instant
of a
specified with respect to the first datum time, to,
Unless otherwise stated, a time
waveform epoch.
2.6.2 Interval
instant
difference calculated by subtracting the time of a first specified
The algebraic time
from the time of a second specified instant.
2.6.3 Duration
or feature exists or
The absolute value of the interval during which a specified waveform
continues.
2.6.4 Period
after which the same characteristics of a periodic
The absolute value of the minimum interval
waveform or a periodic feature recur.
2.6.5 Frequency
The reciprocal of period.
2.6.6 Cycle
through which a periodic waveform or a periodic
The complete range of states or magnitudes
feature passes before repeating itself identically.
2.7 Reference lines and points

The reference lines and points defined in this sub-clause and used throughout the remainder

of this standard are constructions which are (either actually or figuratively) superimposed on

for descriptive or analytical purposes. Unless otherwise specified, all defined lines

waveforms
waveform epoch.
and points lie within a
2.7.1 Time origin line
equal to
time which, unless otherwise specified, has a time
A line of constant and specified
(see Figure 1, page 40).
zero and passes through the first datum time, to, of a waveform epoch
2.7.2 Magnitude origin line
magnitude equal to zero
A line of specified magnitude which, unless otherwise specified, has a
and extends through the waveform epoch (see Figure 1).
2.7.3 Time reference line
A line parallel to the time origin line at a specified instant.
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469-1
0 I E C 1987 19 —
2.7.4 Time referenced point
A point at the intersection of a time reference line
and a waveform.
2.7.5 Magnitude reference line
A line parallel to the magnitude origin line at a specified magnitude.
2.7.6 Magnitude referenced point
A point at the intersection of a magnitude reference line and a waveform.
2.7.7 Knot
A point tk, m k (where k =
1, 2, 3, ..., n) in a sequence of points wherein tk k+ , through
, t
which a cubic natural spline passes (see Figure 3, page 41).
2.7.8 Cubic natural spline
A catenated piecewise sequence of cubic polynomial functions
p (1,2), p (2,3), ...,p (n-1, n)

between knots t, m i and t2 m 2 , t 2 m2 and t3 m 3 , ..., t _o mo i _ 1) and t„ mn,

respectively, wherein:
a) at all
knots, the first and second derivatives of the adjacent polynomial functions are
equal, and

b) for all values of t less than tl and greater than to the function is linear (see Figure 3 and

Sub-clause 5.5).

Note. — The cubic natural spline yields a curve which, throughout, is continuous and has continuous first and second

derivatives. The resulting curve is the rigorous mathematical embodiment of what is conventionally called

a smooth curve drawn through a group of points (i.e. knots) and it consists of a sequence of curvilinear

segments which are defined by equations of the third degree.
2.8 Miscellaneous
2.8.1 Pulse shape

For descriptive purposes, a pulse waveform may be imprecisely described by any of the

adjectives, or combinations thereof, in Sub-clauses 2.4.1.1, 2.4.4, 2.4.5 and 2.5.3.2 to 2.5.3.4,

inclusive. When so used, these adjectives describe general shape only and no precise distinc-

tions are defined.

For tutorial purposes, a hypothetical pulse waveform may be precisely defined by the further

addition of the adjective "ideal" (Sub-clause 2.4.1.2).

For measurement or comparison purposes, a pulse waveform may be precisely defined by

the further addition of the adjective
"reference" (Sub-clause 2.4.1.3).
2.8.2 Transition shape
For descriptive purposes, a
transition waveform may be imprecisely described by any of the

adjectives, or combinations thereof, in Sub-clauses 2.4.1.1, 2.4.4, 2.4.5.5 and 2.5.3. When so

used, these adjectives describe general shape only and no precise distinctions are defined.

For tutorial purposes, a hypothetical transition waveform may be precisely defined by the

further addition of the adjective
"ideal" (Sub-clause 2.4.1.2).
For measurement or comparison purposes, a
transition waveform may be precisely defined
by the further addition of the adjective "reference" (Sub-clause 2.4.1.3).
2.8.3 Pulse power
The power transferred or transformed by a
pulse(s). Unless otherwise specified by a
mathematical adjective (from Sub-clause 2.5.2),
average power over a specified interval is
assumed.
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469-1 © I E C 1987 — 21 —
2.8.4 Pulse energy

The energy transferred or transformed by a pulse(s). Unless otherwise specified by a

mathematical adjective (from Sub-clause 2.5.2), the total energy over a specified interval is

assumed.
3. The single pulse waveform
3.1 Major pulse waveform features
3.1.1 Base
The two portions of a which represent the first nominal state from which
pulse waveform
a pulse departs and to which it ultimately returns.
3.1.2 Top

The portion of a pulse waveform which represents the second nominal state of a pulse.

3.1.3 First transition
The major transition waveform of a pulse waveform between the base and the top.
3.1.4 Last transition
The major transition waveform of a pulse waveform between the top and the base.
3.2 Magnitude characteristics and references

All magnitude characteristics, unless otherwise specified, are derived from data within the

waveform epoch.
3.2.1 Base magnitude

The magnitude of the base as obtained by a specified procedure or algorithm. Unless

otherwise specified, both portions of the base are included in the procedure or algorithm (see

Figure 1, page 40, and I E C Publication 469-2, Sub-clause 4.3.1 for suitable algorithms).

3.2.2 Top magnitude

The magnitude of the top as obtained by a specified procedure or algorithm (see Figure 1

and I E C Publication 469-2, Sub-clause 4.3.1 for suitable algorithms).
3.2.3
Pulse amplitude
and the (see Figure 1).
The algebraic difference between the top magnitude base magnitude
3.2.4
Per cent reference magnitude
reference magnitude specified by:
(x) % MI 00 (Mt—Mb)
= Mb Tc—,6
where :
0 (x) % Mr = per cent reference magnitude
Mb =
base magnitude
Mt = top magnitude
(x)
Mb, Mt and % M r are all in the same unit of measurement
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469-1 © I E C 1987 — 23 —
3.2.5 Magnitude reference lines
3.2.5.1 Base line (Top line)

The magnitude reference line at the base (top) magnitude (see Figure 1, page 40).

3.2.5.2 Proximal (distal) line

A magnitude reference line at a specified magnitude in the proximal (distal) region of a pulse

waveform. Unless otherwise specified, the proximal (distal) line is at the 10 (90) per cent

reference magnitude (see Figure 1).
3.2.5.3 Mesial line
A mesial region of a pulse waveform.
magnitude reference line at a specified magnitude in the

Unless otherwise specified, the mesial line is at the 50 per cent reference magnitude (see

Figure 1).
3.2.6 Magnitude reference point
3.2.6.1 Proximal (distal) point

A magnitude referenced point at the intersection of a waveform and a proximal (distal) line

(see Figure 1).
3.2.6.2 Mesial point

A magnitude referenced point at the intersection of a waveform and a mesial line (see

Figure 1).
3.3 Time characteristics and references
3.3.1 Pulse start (stop) time
The on the first (last) transition of a
instant specified by a magnitude referenced point pulse

waveform. Unless otherwise specified, the pulse start (stop) time is at the mesial point on the

first (last) transition (see Figure 1).
3.3.2 Pulse duration
The duration between pulse start time and pulse stop time (see Figure 1).
3.3.3 Transition duration

The duration between the proximal point and the distal point on a transition waveform.

3.3.3.1 First (last) transition duration

The transition duration of the first (last) transition waveform in a pulse waveform (see

Figure 1).
Note. — Previously called "rise (fall) time".
3.3.4 Time reference lines
3.3.4.1 Pulse start (stop) line
The time reference line (see Figure 1).
at pulse start (stop) time
3.3.4.2 Top centre line

The time reference line at the average of pulse start time and pulse stop time (see Figure 1).

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469-1 © I E C 1987 — 25 —
3.3.5 Pulse time reference points
3.3.5.1 Top centre point

A specified time referenced point or magnitude referenced point on a pulse waveform top. If

no point is specified, the top centre point is the time referenced point at the intersection of a

pulse waveform and the top centre line (see Figure 1).
3.3.5.2 First (last) base point
(compare with base
Unless otherwise specified, the first (last) datum point in a pulse epoch
centre point, Sub-clause 5.3.2.7) (see Figure 1, page 40).
3.4 Other pulse waveform features
3.4.1 Pulse corner

A continuous pulse waveform feature of specified extent which includes a region of

maximum curvature or a point of discontinuity in the waveform slope. Unless otherwise

specified, the extent of the corners in a rectangular or a trapezoidal pulse waveform are as

specified in the following table:
Corner First point Last point
First transition proximal point
First First base point
Second First transition distal point Top centre point
Third Top centre point Last transition distal point
Fourth Last transition proximal point Last base point
3.4.2 Pulse quadrant

One of the four continuous and contiguous pulse waveform features of specified extent which

include a region of maximum curvature or a point of discontinuity in the waveform slope.

Unless otherwise specified, the extent of the quadrants in a rectangular or a trapezoidal pulse

waveform are as specified in the following table:
Quadrant First point Last point
First First base point First transition mesial point
Top centre point
Second First transition mesial point
Third Top centre point Last transition mesial point
Fourth Last transition mesial point Last base point
4. The single transition waveform
4.1 Step

A transition waveform which has a transition duration which is negligible relative to the

duration of the waveform epoch or to the duration of its adjacent first and second nominal

states.
4.2 Ramp
linear feature.
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469-1 © I E C 1987 27 —
Complex waveforms
5.1 Combinations of pulses and transitions
5.1.1 Double pulse

Two pulse waveforms of the same polarity which are adjacent in time and which are

considered or treated as a single feature.
5.1.2
Bipolar pulse

Two pulse waveforms of opposite polarity which are adjacent in time and which are consid-

ered or treated as a single feature.
5.1.3 Staircase
of steps of equal magnitude and
Unless otherwise specified, a periodic and finite sequence
of the same polarity.
5.2 Waveforms produced by magnitude superposition
5.2.1 Offset

The algebraic difference between two specified magnitude reference lines. Unless otherwise

specified, these two magnitude reference lines are the waveform base line and the magnitude

origin line (see Figure 1, page 40), in which case the offset is the base magnitude (see

Sub-clause 3.2.1).
5.2.2 Offset waveform

A waveform whose base line is offset from, unless otherwise specified, the magnitude origin

line.
5.2.3 Composite waveform
which is, or which for analytical or descriptive purposes is treated as, the
A waveform
algebraic summation of two or more waveforms (see Figure 2, page 41).
5.3 Waveforms produced by continuous time superposition of simpler waveforms
5.3.1 Pulse train
A continuous repetitive sequence of pulse waveforms.
5.3.2 Pulse train time-related definitions
5.3.2.1 Pulse repetition period

The interval between the pulse start time of a first pulse waveform and the pulse start time

of the immediately following pulse waveform in a periodic pulse train.
5.3.2.2 Pulse repetition frequency
The reciprocal of pulse repetition period.
5.3.2.3 Pulse separation

The interval between the pulse stop time of a first pulse waveform and the pulse start time

of the immediately following pulse waveform in a pulse train.
5.3.2.4 Duty factor

Unless otherwise specified, the ratio of the pulse waveform duration to the pulse repetition

period of a periodic pulse train.
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469-1 © I E C 1987 29
5.3.2.5 On/off ratio

Unless otherwise specified, the ratio of the pulse waveform duration to the pulse separation

of a periodic pulse train.
5.3.2.6 Base centre line
pulse stop time of a first pulse waveform and
The time reference line at the average of the
of the immediately following pulse waveform in a pulse train.
the pulse start time
5.3.2.7 Base centre point
on a pulse train waveform
A specified time referenced point or magnitude referenced point
time referenced point at the intersection
base. If no point is specified, the base centre point is the
and a base centre line (compare with first (last) base point,
of a pulse train waveform base
Sub-clause 3.3.5.2).
5.3.2.8 Pulse train epoch
data are known or knowable and which
The span of time in a pulse train for which waveform
to the immediately following base centre point.
extends from a first base centre point
5.3.3 Square wave

A periodic rectangular pulse train with a duty factor of 0.5 or an on/off ratio of 1.

5.4 Waveforms produced by non-continuous time superposition of simpler waveforms
5.4.1 Pulse burst
A finite sequence of pulse waveforms.
5.4.2 Pulse burst time-related definitions
5.4.2.1 Pulse burst duration
pulse start time of the first pulse waveform and the pulse stop time
The interval between the
of the last pulse waveform in a pulse burst.
5.4.2.2 Pulse burst separation

The interval between the pulse stop time of the last pulse waveform in a pulse burst and the

pulse start time of the first pulse waveform in the immediately following pulse burst.

5.4.2.3 Pulse burst repetition period
pulse waveform in a pulse burst and the
The interval between the pulse start time of the first
in the immediately following pulse burst in a
pulse start time of the first pulse waveform
sequence of periodic pulse bursts.
5.4.2.4 Pulse burst repetition frequency
The reciprocal of pulse burst repetition period.
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5.5 Waveforms produced by operations on waveforms
cubic natural spline (or its related
All envelope definitions in this sub-clause are based on the
at specified points.
approximation, the draughtsman's spline) with knots

All burst envelopes extend in time from the first to the last knot specified, the remainder of

the waveform being:
which precedes the first knot, and
a) that portion of the waveform
b) that portion of the waveform which follows the last knot.

Burst envelopes and their adjacent waveform bases, taken together, comprise a continuous

of the

waveform which has a continuous first derivative except at the first and last knots

envelope.
5.5.1 Pulse train top (base) envelope

Unless otherwise specified, the waveform defined by a cubic natural spline with knots at each

point of intersection of the to
...