IEC 60728-3:2010

IEC 60728-3 ®
Edition 4.0 2010-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Cable networks for television signals, sound signals and interactive services –
Part 3: Active wideband equipment for cable networks

Réseaux de distribution par câbles pour signaux de télévision, signaux de
radiodiffusion sonore et services interactifs –
Partie 3: Matériel actif à large bande pour réseaux de distribution par câbles

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by

any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or

IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
 Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
 IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
 Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
 Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) est la première organisation mondiale qui élabore et publie des
normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
 Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
 Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
 Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
 Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: csc@iec.ch
Tél.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 60728-3 ®
Edition 4.0 2010-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Cable networks for television signals, sound signals and interactive services –
Part 3: Active wideband equipment for cable networks

Réseaux de distribution par câbles pour signaux de télévision, signaux de
radiodiffusion sonore et services interactifs –
Partie 3: Matériel actif à large bande pour réseaux de distribution par câbles

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XB
ICS 33.060.40; 33.170 ISBN 978-2-88912-576-0

– 2 – 60728-3  IEC:2010
CONTENTS
FOREWORD . 6

INTRODUCTION . 8

1 Scope . 9

2 Normative references . 9

3 Terms, definitions, symbols and abbreviations . 11

3.1 Terms and definitions . 11

3.2 Symbols . 15

3.3 Abbreviations . 16
4 Methods of measurement . 17
4.1 General . 17
4.2 Linear distortion . 18
4.2.1 Return loss . 18
4.2.2 Flatness . 19
4.2.3 Chrominance/luminance delay inequality for PAL/SECAM only . 19
4.3 Non-linear distortion . 20
4.3.1 General . 20
4.3.2 Types of measurements . 20
4.3.3 Intermodulation. 20
4.3.4 Composite triple beat . 22
4.3.5 Composite second order beat . 25
4.3.6 Composite crossmodulation . 26
4.3.7 Method of measurement of non-linearity for pure digital channel load . 29
4.3.8 Hum modulation of carrier . 29
4.4 Automatic gain and slope control step response . 33
4.4.1 Definitions . 33
4.4.2 Equipment required . 33
4.4.3 Connection of equipment . 34
4.4.4 Measurement procedure . 34
4.5 Noise figure . 35
4.5.1 General . 35
4.5.2 Equipment required . 35
4.5.3 Connection of equipment . 35

4.5.4 Measurement procedure . 35
4.6 Crosstalk attenuation. 36
4.6.1 Crosstalk attenuation for loop through ports . 36
4.6.2 Crosstalk attenuation for output ports . 36
4.7 Signal level for digitally modulated signals . 38
4.8 Measurement of composite intermodulation noise ratio (CINR) . 38
4.8.1 General . 38
4.8.2 Equipment required . 38
4.8.3 Connection of equipment . 39
4.8.4 Measurement procedure . 40
4.8.5 Presentation of the results . 40
4.9 Immunity to surge voltages . 41
4.9.1 General . 41
4.9.2 Equipment required . 42

60728-3  IEC:2010 – 3 –
4.9.3 Connection of equipment . 42

4.9.4 Measurement procedure . 42

5 Equipment requirements . 42

5.1 General requirements . 42

5.2 Safety . 43

5.3 Electromagnetic compatibility (EMC) . 43

5.4 Frequency range . 43

5.5 Impedance and return loss . 43

5.6 Gain . 44

5.6.1 Minimum and maximum gain . 44
5.6.2 Gain control . 44
5.6.3 Slope and slope control . 44
5.7 Flatness . 44
5.8 Test points . 45
5.9 Group delay . 45
5.9.1 Chrominance/luminance delay inequality . 45
5.9.2 Chrominance/luminance delay inequality for other television
standards and modulation systems . 45
5.10 Noise figure . 45
5.11 Non-linear distortion . 45
5.11.1 General . 45
5.11.2 Second order distortion . 45
5.11.3 Third order distortion . 45
5.11.4 Composite triple beat . 46
5.11.5 Composite second order . 46
5.11.6 Composite crossmodulation . 46
5.11.7 Maximum operating level for pure digital channel load . 46
5.12 Automatic gain and slope control . 46
5.13 Hum modulation . 46
5.14 Power supply . 46
5.15 Environmental . 47
5.15.1 General . 47
5.15.2 Storage (simulated effects of) . 47
5.15.3 Transportation . 47
5.15.4 Installation or maintenance . 47

5.15.5 Operation . 47
5.15.6 Energy efficiency of equipment . 47
5.16 Marking . 47
5.16.1 Marking of equipment . 47
5.16.2 Marking of ports . 47
5.17 Mean operating time between failure (MTBF) . 48
5.18 Requirements for multi-switches . 48
5.18.1 Control signals for multi-switches . 48
5.18.2 Amplitude frequency response flatness . 48
5.18.3 Return loss . 48
5.18.4 Through loss . 48
5.18.5 Isolation . 48
5.18.6 Crosstalk attenuation . 48
5.18.7 Satellite IF to terrestrial signal isolation . 48

– 4 – 60728-3  IEC:2010
5.19 Immunity to surge voltages . 49

5.19.1 Degrees of testing levels . 49

5.19.2 Recommendation of testing level degree . 49

Annex A (informative) Derivation of non-linear distortion . 50

Annex B (normative) Test carriers, levels and intermodulation products . 52

Annex C (normative) Checks on test equipment . 54

Annex D (informative) Test frequency plan for composite triple beat (CTB), composite
second order (CSO) and crossmodulation (XM) measurement . 55

Annex E (informative) Measurement errors which occur due to mismatched equipment . 56

Annex F (informative) Examples of signals, methods of measurement and network
design for return paths . 57
Bibliography . 64

Figure 1 – Maximum error a for measurement of return loss using VSWR-bridge with
directivity D = 46 dB and 26 dB test port return loss . 18
Figure 2 – Measurement of return loss . 19
Figure 3 – Basic arrangement of test equipment for evaluation of the ratio of signal to
intermodulation product . 21
Figure 4 – Connection of test equipment for the measurement of non-linear distortion
by composite beat . 24
Figure 5 – Connection of test equipment for the measurement of composite
crossmodulation. 28
Figure 6 – Carrier/hum ratio . 30
Figure 7 – Test set-up for local-powered objects . 31
Figure 8 – Test set-up for remote-powered objects . 31
Figure 9 – Oscilloscope display . 32
Figure 10 – Time constant T . 33
c
Figure 11 – Measurement of AGC step response . 34
Figure 12 – Measurement of noise figure . 35
Figure 13 – Measurement of crosstalk attenuation for loop trough ports of multi-
switches . 37
Figure 14 – Characteristic of the noise filter . 39
Figure 15 – Test setup for the non-linearity measurement . 39

Figure 16 – Presentation of the result of CINR . 41
Figure 17 – Measurement set-up for surge immunity test . 42
Figure B.1 – An example showing products formed when 2ƒ > ƒ . 52
a b
Figure B.2 – An example showing products formed when 2ƒ < ƒ . 53
a b
Figure B.3 – Products of the form ƒ ± ƒ ± ƒ . 53
a b c
Figure E.1 – Error concerning return loss measurement . 56
Figure E.2 – Maximum ripple . 56
Figure F.1 – Spectrum of a QPSK-modulated signal . 57
Figure F.2 – Measurement of non-linearity using wideband noise . 59
Figure F.3 – Network used in the design example . 60
Figure F.4 – A test result measured from a real 20 dB return amplifier . 61
Figure F.5 – The CINR curve of one amplifier is modified to represent the CINR of the
whole coaxial section of the network . 62

60728-3  IEC:2010 – 5 –
Figure F.6 – The CINR of an optical link as a function of OMI, example . 63

Table 1 – Correction factors where the modulation used is other than 100 % . 26

Table 2 – Notch filter frequencies . 39

Table 3 – Return loss requirements for all equipment . 44

Table 4 – Parameters of surge voltages for different degrees of testing levels . 49

Table 5 – Recommendations for degree of testing levels . 49

Table D.1 – Frequency allocation plan . 55

Table F.1 – Application of methods of measurement in IEC 60728-3 for return path
equipment . 58
Table F.2 – Application of methods of measurement in IEC 60728-6 for return path
equipment . 58

– 6 – 60728-3  IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
CABLE NETWORKS FOR TELEVISION SIGNALS,

SOUND SIGNALS AND INTERACTIVE SERVICES –

Part 3: Active wideband equipment for cable networks

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote interna-
tional co-operation on all questions concerning standardization in the electrical and electronic fields. To this
end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Tech-
nical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publica-
tion(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the
subject dealt with may participate in this preparatory work. International, governmental and non-governmental
organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the Interna-
tional Organization for Standardization (ISO) in accordance with conditions determined by agreement between
the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all inter-
ested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinter-
pretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence be-
tween any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and ex-
penses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publica-
tions.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of pa-
tent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60728-3 has been prepared by technical area 5: Cable networks
for television signals, sound signals and interactive services, of IEC technical committee 100:
Audio, video and multimedia systems and equipment.
This fourth edition cancels and replaces the third edition published in 2005 of which it consti-
tutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• extension of upper frequency range limit for cable network equipment from 862 MHz to
1 000 MHz;
• method of measurement and requirements for immunity to surge voltages;
• extension of scope to equipment using symmetrical ports;
• additional normative references;

60728-3  IEC:2010 – 7 –
• additional terms and definitions and abbreviations.

This bilingual version, published in 2011-07, corresponds to the English version.

The text of this standard is based on the following documents:

FDIS Report on voting
100/1746/FDIS 100/1766/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The list of all the parts of the IEC 60728 series, under the general title Cable networks for tel-
evision signals, sound signals and interactive services, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data re-
lated to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understand-
ing of its contents. Users should therefore print this document using a colour printer.

– 8 – 60728-3  IEC:2010
INTRODUCTION
Standards of the IEC 60728 series deal with cable networks including equipment and associ-

ated methods of measurement for headend reception, processing and distribution of television

signals, sound signals and their associated data signals and for processing, interfacing and

transmitting all kinds of signals for interactive services using all applicable transmission me-

dia.
This includes
• CATV -networks;
• MATV-networks and SMATV-networks;
• individual receiving networks;
and all kinds of equipment, systems and installations installed in such networks.
For active equipment with balanced RF signal ports this standard applies to those ports which
carry RF broadband signals for services as described in the scope of this standard.
The extent of this standardization work is from the antennas and/or special signal source in-
puts to the headend or other interface points to the network up to the terminal input.
The standardization of any user terminals (i.e., tuners, receivers, decoders, multimedia termi-
nals, etc.) as well as of any coaxial, balanced and optical cables and accessories thereof is
excluded.
___________
This word encompasses the HFC (Hybrid Fibre Cable) networks used nowadays to provide telecommunications
services, voice, data, audio and video both broadcast and narrowcast.

60728-3  IEC:2010 – 9 –
CABLE NETWORKS FOR TELEVISION SIGNALS,

SOUND SIGNALS AND INTERACTIVE SERVICES –

Part 3: Active wideband equipment for cable networks

1 Scope
This part of IEC 60728 lays down the measuring methods, performance requirements and da-
ta publication requirements for active wideband equipment of cable networks for television
signals, sound signals and interactive services.
This standard
• applies to all broadband amplifiers used in cable networks;
• covers the frequency range 5 MHz to 3 000 MHz;
NOTE The upper limit of 3 000 MHz is an example, but not a strict value. The frequency range, or ranges, over
which the equipment is specified, should be published.
• applies to one-way and two-way equipment;
• lays down the basic methods of measurement of the operational characteristics of the ac-
tive equipment in order to assess the performance of this equipment;
• identifies the performance specifications to be published by the manufacturers;
• states the minimum performance requirements of certain parameters.
Amplifiers are divided into the following two quality levels:
Grade 1: amplifiers typically intended to be cascaded;
Grade 2: amplifiers for use typically within an apartment block, or within a single residence,
to feed a few outlets.
Practical experience has shown that these types meet most of the technical requirements
necessary for supplying a minimum signal quality to the subscribers. This classification is not
a requirement but is provided to users and manufacturers for information about minimum
quality criteria of the material required to install networks of different sizes. The system op-
erator has to select appropriate material to meet the minimum signal quality at the subscrib-
er’s outlet, and to optimise cost/performance, taking into account the size of the network and
local circumstances.
All requirements and published data are understood as guaranteed values within the specified
frequency range and in well-matched conditions.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60065, Audio, video and similar electronic apparatus – Safety requirements
IEC 60068-1:1998, Environmental testing – Part 1: General and guidance
IEC 60068-2-1, Environmental testing – Part 2-1: Tests – Tests A: Cold

– 10 – 60728-3  IEC:2010
IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Tests B: Dry heat

IEC 60068-2-6, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)

IEC 60068-2-14, Environmental testing – Part 2-14: Tests – Test N: Change of temperature

IEC 60068-2-27, Environmental testing – Part 2-27: Tests – Test Ea and guidance: Shock

IEC 60068-2-29, Basic environmental testing procedures – Part 2-29: Tests – Test Eb and

guidance: Bump
IEC 60068-2-30, Environmental testing – Part 2-30: Tests – Test dB: Damp heat, cyclic

(12 h + 12 h cycle)
IEC 60068-2-31, Environmental testing – Part 2-31: Tests – Test Ec: Rough handling
shocks, primarily for equipment-type specimens
IEC 60068-2-32, Basic environmental testing procedures – Part 2-32: Tests – Test Ed: Free
fall
IEC 60068-2-40, Basic environmental testing procedures – Part 2-40: Tests – Test Z/AM:
Combined cold/low air pressure tests
IEC 60068-2-48, Basic environmental testing procedures – Part 2-48: Tests – Guidance on
the application of the tests of IEC publication 60068 to simulate the effects of storage
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 60728-1, Cable networks for television signals, sound signals and interactive services –
Part 1: System performance of forward paths
IEC 60728-2, Cable networks for television signals, sound signals and interactive services –
Part 2: Electromagnetic compatibility for equipment
IEC 60728-4, Cable networks for television signals, sound signals and interactive services –
Part 4: Passive wideband equipment for coaxial cable networks
IEC 60728-5, Cable networks for television signals, sound signals and interactive services –
Part 5: Headend equipment
IEC 60728-11, Cable networks for television signals, sound signals and interactive ser-
vices – Part 11: Safety
IEC 60950-1, Information technology equipment – Safety – Part 1: General requirements

IEC 61000-4-5, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement
techniques – Surge immunity test
IEC 61319-1, Interconnections of satellite receiving equipment – Part 1: Europe
IEC 61319-2, Interconnections of satellite receiving equipment – Part 2: Japan
ITU-T Recommendation G.117, Transmission systems and media – Digital systems and net-
works – International telephone connections and circuits – General recommendations on the
transmission quality for an entire international telephone connection – Transmission aspects
of unbalance about earth
ITU-T Recommendation O.9, Specifications of measuring equipment – General – Measuring
arrangements to assess the degree of unbalance about earth

60728-3  IEC:2010 – 11 –
3 Terms, definitions, symbols and abbreviations

For the purposes of this document, the following terms, definitions, symbols and abbreviations

apply.
3.1 Terms and definitions
3.1.1
amplitude frequency response
gain or loss of an equipment or system plotted against frequency

3.1.2
attenuation
ratio of the input power to the output power of an equipment or system, usually expressed in
decibels
3.1.3
balun
device to match symmetrical impedance 100 Ω (balanced) to un-symmetrical impedance 75 Ω
(unbalanced) and vice-versa
3.1.4
carrier-to-noise ratio
difference in decibels between the vision or sound carrier level at a given point in an equip-
ment or system and the noise level at that point (measured within a bandwidth appropriate to
the television or radio system in use)
3.1.5
chrominance-luminance delay inequality
difference in transmission delay of chrominance and luminance signals, which results in the
spilling of colour to left or right of the area of corresponding luminance
[IEC 60050-723:1997, 723-06-61]
3.1.6
composite intermodulation noise
CIN
sum of noise and intermodulation products from digital modulated signals
3.1.7
composite intermodulation noise ratio
CINR
ratio of the signal level and the CIN level
3.1.8
crossmodulation
undesired modulation of the carrier of a desired signal by the modulation of another signal as
a result of equipment or system non-linearities
3.1.9
crosstalk attenuation
unwanted signals beside the wanted signal on a lead caused by electromagnetic coupling be-
tween leads; ratio of the wanted signal power to the unwanted signal power, while equal sig-
nal powers are applied to the leads
NOTE Crosstalk attenuation is usually expressed in decibels.

– 12 – 60728-3  IEC:2010
3.1.10
decibel ratio
ten times the logarithm of the ratio of two quantities of power P and P , i.e.
1 2
P
10lg in dB
P
3.1.11
equaliser
device designed to compensate over a certain frequency range for the amplitude/frequency

distortion or phase/frequency distortion introduced by feeders or equipment

NOTE This device is for the compensation of linear distortions only.
3.1.12
feeder
transmission path forming part of a cable network
NOTE Such a path may consist of a metallic cable, optical fibre, waveguide or any combination of them. By ex-
tension, the term is also applied to paths containing one or more radio links.
3.1.13
gain
ratio of the output power to the input power, usually expressed in decibels
3.1.14
ideal thermal noise
noise generated in a resistive component due to the thermal agitation of electrons
NOTE The thermal power generated is given by
P= 4⋅ B⋅ k⋅ T
where
P is the noise power in watts;
B is the bandwidth in hertz;
–23
k is the Boltzmann's constant = 1,38·10 J/K;
T is the absolute temperature in kelvins.
It follows that
U
= 4⋅ B⋅ k⋅ T
R
and
U= 4⋅ R⋅ B⋅ k⋅ T
where
U is the noise voltage (e.m.f.);
R is the resistance in ohms.
In practice, it is normal for the source to be terminated with a load equal to the internal resistance value, the noise
voltage at the input is then U/2.
3.1.15
level
decibel ratio of any power P to the standard reference power P , i.e.
1 0
60728-3  IEC:2010 – 13 –
P
10 lg
P
decibel ratio of any voltage U to the standard reference voltage U , i.e.
1 0
U
20 lg
U
NOTE The power level may be expressed in decibels relative to P = (U /R) = (1/75) pW, i.e. in dB(P ), taking

0 0 0
into account that the level of P corresponds to 0 dB(P ) or, as more usually, in dB(pW), taking into account that
0 0
the level of P corresponds to –18,75 dB(pW). The voltage level is expressed in decibels relative to 1 µV (across
75 Ω), i.e. in dB(µV).
3.1.16
modulation error ratio
MER
sum of the squares of the magnitudes of the ideal symbol vectors is divided by the sum of the
squares of the magnitudes of the symbol error vectors of a sequence of symbols, the result
being expressed as a power ratio in dB
N


2 2


(I + Q )
j j
∑


 
j=1
MER= 10 lg in dB
 
N
 
2 2
(δI +δQ )
∑ j j
 

j=1 


3.1.17
multi-switch
equipment used in distribution systems for signals that are received from satellites and con-
verted to a suitable IF
NOTE The IF signals that are received from different polarisations, frequency bands and orbital positions are in-
put signals to the multi-switch. Subscriber feeders are connected to the multi-switch output ports. Each output port
is switched to one of the input ports, depending on control signals that are transmitted from the subscriber equip-
ment to the multi-switch. Besides a splitter for each input port and a switch for each output port, a multi-switch can
contain amplifiers to compensate for distribution or cable losses.
3.1.18
multi-switch loop through port
one or more ports to loop through the input signals through a multi-switch

NOTE This enables larger networks with multiple multi-switches, each one installed close to a group of subscrib-
ers. The multi-switches are connected in a loop through manner. The IF signals that are received by an outdoor
unit from different polarisations, frequency bands and orbital positions are input signals to a first multi-switch. Ca-
bles connect the loop through ports of this multi-switch to the input ports of a second multi-switch and so on.
3.1.19
multi-switch port for terrestrial signals
port in a multi-switch used to distribute terrestrial signals in addition to the signals received
from satellites
3.1.20
noise factor/noise figure
used as figures of merit describing the internally generated noise of an active device
NOTE The noise factor, F, is the ratio of the carrier-to-noise ratio at the input, to the carrier-to-noise ratio at the
output of an active device.
– 14 – 60728-3  IEC:2010
C /N
1 1
F=
C /N
2 2
where
C is the signal power at the input;
C is the signal power at the output;
N is the noise power at the input (ideal thermal noise);
N is the noise power at the output.
In other words, the noise factor is the ratio of noise power at the output of an active device to the noise power at
the same point if the device had been ideal and added no noise.
N
2actual
F=
N
2ideal
The noise factor is dimensionless and is often expressed as noise figure, NF, in dB
NF = 10 lg F   in dB
3.1.21
slope
difference in gain or attenuation at two specified frequencies between any two points in an
equipment or system
NOTE The slope sign is considered
a) negative when the attenuation increases with frequency (cables) or the gain (amplifiers) decreases with fre-
quency,
b) positive when the gain (amplifiers) increases with frequency (compensating slope).
3.1.22
standard reference power and voltage
in cable networks, the standard reference power, P , is (1/75) pW
NOTE 1 This is the power dissipated in a 75 Ω resistor with an RMS voltage drop of 1 µV across it.
NOTE 2 The standard reference voltage, U , is 1 µV.
3.1.23
surge voltage
produced by a direct or indirect lightning stroke
3.1.24
well-matched
matching condition when the return loss of the equipment complies with the requirements of
Table 3
NOTE Through mismatching of measurement instruments and the measurement object, measurement errors are
possible. Comments to the estimation of such errors are given in Annex E.

60728-3  IEC:2010 – 15 –
3.2 Symbols
The following graphical symbols are used in the figures of this standard. These symbols are

either listed in IEC 60617 or based on symbols defined in IEC 60617.

Symbols Terms Symbols Terms
Amperemeter Voltmeter
based on based on
V
A
[IEC 60617-S00910 [IEC 60617-S00910

(2001-07)] (2001-07)]
Power meter
based on
Selective voltmeter W
V
[IEC 60617-S00910
(2001-07)]
Signal generator
Equipment Under Test
based on
based on
G
EUT
[IEC 60617-S00899,
[IEC 60617-S00059
IEC 60617-S01403
(2001-07)]
(2001-07)]
Variable signal genera-
tor
Noise generator based on
[IEC 60617-S01230 G [IEC 60617-S00081,
G
(2001-07)] IEC 60617-S00899,
kT
IEC 60617-S01403
(2001-09)]
Surge generator
G
[IEC 60617-S01228 VSWR-bridge
(2001-07)]
High-pass filter Low-pass filter
[IEC 60617-S01247 [I
...