EN 50083-5:2001

SLOVENSKI STANDARD
01-december-2003
1DGRPHãþD
SIST EN 50083-5:1995
Cable networks for television signals, sound signals and interactive services - Part
5: Headend equipment
Cable networks for television signals, sound signals and interactive services -- Part 5:
Headend equipment
Kabelnetze für Fernsehsignale, Tonsignale und interaktive Dienste -- Teil 5: Geräte für
Kopfstellen
Réseaux de distribution par câbles pour signaux de télévision, signaux de radiodiffusion
sonore et services interactifs -- Partie 5: Matériels de tête de réseau
Ta slovenski standard je istoveten z: EN 50083-5:2001
ICS:
33.060.40 Kabelski razdelilni sistemi Cabled distribution systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50083-5
NORME EUROPÉENNE
EUROPÄISCHE NORM March 2001
ICS 33.060.40 Supersedes EN 50083-5:1994
English version
Cable networks for television signals, sound signals and
interactive services
Part 5: Headend equipment
Réseaux de distribution par câbles Kabelnetze für Fernsehsignale,
pour signaux de télévision, signaux Tonsignale und interaktive Dienste
de radiodiffusion sonore et services Teil 5: Geräte für Kopfstellen
interactifs
Partie 5: Matériels de tête de réseau
This European Standard was approved by CENELEC on 1998-01-01. 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-date 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 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, Czech
Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg,
Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50083-5:2001 E
Foreword
This European Standard was prepared by CENELEC Technical Committee TC 209, "Cable
networks for television signals, sound signals and interactive services" on the basis of
EN 50083-5:1994 and the first amendment to EN 50083-5.
The text of this first amendment was submitted to the Unique Acceptance Procedure and was
approved by CENELEC on 1998-01-01 with the request to prepare a second edition of
EN 50083-5, by incorporating this amendment into the European Standard EN 50083-5:1994.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2001-10-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2001-10-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annexes A, B and D are normative and annexes C and E are informative.
__________
- 3 - EN 50083-5: 2001
Contents
Page
1 Scope.4
1.1 General.4
1.2 Specific scope of this part 5.4
2 Normative references.7
3 Terms, definitions, symbols and abbreviations.8
3.1 Terms and definitions .8
3.2 Symbols.11
3.3 Abbreviation.12
4 Methods of measurement.13
4.1 Single-channel intermodulation.13
4.2 Three-carrier intermodulation measurement.14
4.3 Two carrier intermodulation measurements for second and third order products .15
4.4 Carrier-to-spurious signal ratio at the output.16
4.5 Television carrier-to-noise ratio.18
4.6 Differential gain and phase for PAL/SECAM signals .22
4.7 Group delay variation.26
4.8 2T-pulse response, K-factor .27
4.9 Chrominance-luminance delay inequalities (20T-pulse method).28
4.10 Luminance non-linearity.30
4.11 Intermodulation distortion (FM stereo radio) .30
4.12 Decoding margin (Teletext).31
4.13 Hum modulation of carrier.33
5 Performance requirements and recommendations .36
5.1 Safety .36
5.2 Electromagnetic compability .36
5.3 Environmental.36
5.4 Marking.36
5.5 Mean time operation between failure (MTBF).37
6 Signal requirements .37
6.1 Indoor units.37
6.2 Outdoor units .40
7 Data publication requirements.40
7.1 General.40
7.2 Indoor units - TV (AM and FM).41
7.3 Indoor units - FM radio.45
7.4 Outdoor units .46
Annex A (normative) Definition of the specified test frequency range for
return loss and noise figure .48
Annex B (normative) Audio connector .49
Annex C (informative) Selectivity diagram for adjacent channel transmission .50
Annex D (normative) Special national conditions .54
Annex E (informative) Measurement errors which occur due to missmatched equipment.55

1 Scope
1.1 General
Standards of EN 50083 series deal with cable networks for television signals, sound signals and
interactive services including equipment, systems and installations
• for headend reception, processing and distribution of television and sound signals and
their associated data signals and
• for processing, interfacing and transmitting all kinds of signals for interactive services
using all applicable transmission media.

All kinds of networks like
• CATV-networks,
• MATV-networks and SMATV-networks,
• Individual receiving networks
and all kinds of equipment, systems and installations installed in such networks, are within this
scope.
The extent of this standardization work is from the antennas, special signal source inputs to the
headend or other interface points to the network up to the system outlet or the terminal input,
where no system outlet exists.

The standardization of any user terminals (i.e. tuners, receivers, decoders, multimedia terminals
etc.) as well as of any coaxial and optical cables and accessories therefor is excluded.
1.2 Specific scope of this part 5
This standard defines the characteristics of equipment used in the headends of terrestrial
broadcast and satellite receiving systems (without satellite outdoor units and without those
broadband amplifiers in the headend as described in EN 50083-3). The satellite outdoor units
for FSS are described in standard ETS 300 158, for BSS in standard ETS 300 249. Test
methods for both types (FSS and BSS) of satellite outdoor units are laid down in ETS 300 457.
This standard
• covers the frequency range 5 MHz to 3000 MHz;
• identifies performance requirements for certain parameters;
• lays down data publication requirements for certain parameters;
• stipulates methods of measurements;
• introduces minimum requirements defining quality grades (Q-grades).
As far as possible this standard only deals with the interfaces between headend equipment and
only explains the function of the equipment if this is necessary to support the description of the
interfaces.
Coder, transcoder, encrypter, decrypter etc. are not described in this standard. If such
equipment are used in headends, the relevant parameters for RF, video, audio and data
interfaces have to be met.
According to the definitions in clause 3 the headends are divided into the following three quality
grades:
Grade 1: local headend / remote headend
Grade 2: hub headend
Grade 3: MATV headend / individual reception headend

- 5 - EN 50083-5: 2001
Practical experience has shown these types meet most of the technical requirements necessary
for supplying a minimum signal quality to the subscribers. This classification shall not be
considered as a requirement but as the information for users and manufacturers on the
minimum quality criteria of the material required to install networks of different sizes. The system
operator has to select appropriate material to meet the minimum signal quality at the
subscriber's outlet and to optimise cost performance, taking into account the size of the network
and local circumstances.
Terrestrial and/or
Satellite Reception
Remote
Headend
Terrestrial and
Satellite Reception
Local
Headend
Hub
Headend
Figure 1 - Example of headends

OUTDOOR INDOOR
Demodulator Transcoder Modulator
Antennas
+
Preamplifier
VHF/UHF
FM Radio, DAB
f
f
Pilot
Data
Video Encoder
Audio
Polarizer
f
Video
f
Audio
LNB
M
VHF/UHF
FM-TV
1st SAT IF
ETS 300 158
ETS 300 249
FM-TV
1st SAT IF
f
f
Figure 2 - Example of headend
Polarmount
- 7 - EN 50083-5: 2001
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions
of any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies.
EN 50083 Cable networks for television signals, sound signals and interactive
services
EN 50083-1 1993 Part 1: Safety requirements
+ A1 1997
+ A2 1997
EN 50083-2 1995 Part 2: Electromagnetic compatibility for equipment
+ A1 1997
EN 50083-3 1998 Part 3: Active wideband equipment for coaxial cable networks
EN 60068/HD 323 series Environmental testing/Basic environmental testing procedures
(IEC 60068 series)
EN 60130-9 2000 Connectors for frequencies below 3 MHz – Part 9: Circular
connectors for radio and associated sound equipment
(IEC 60130-9:2000)
EN 60244-5 1994 Methods of measurement for radio transmitters
Part 5: Performance characteristics for television transmitters
(IEC 60244-5:1992)
EN 60417-1 1999 Graphical symbols for use on equipment
Part 1: Overview and application (IEC 60417-1:1998)
EN 60417-2 1999 Graphical symbols for use on equipment
Part 2: Symbol originals (IEC 60417-2:1998)
EN 60529 1991 Degrees of protection provided by enclosures (IP Code)
+ corr. May 1993 NOTE: Basic Safety Publication
(IEC 60529:1989)
EN 300 163 1998 Television systems - NICAM 728: Transmission of two-channel
V1.2.1 digital sound with terrestrial television systems B, G, H, I, K1 and L
EN 300 473 1997 Digital Video Broadcasting (DVB) - Satellite Master Antenna
V1.1.2 Television (SMATV) distribution systems
HD 134.2 S2 1984 Radio frequency connectors - Part 2: Coaxial unmatched connector
(IEC 60169-2:1965 + A1:1982)
HD 571 S1 1990 General principles for the creation of graphical symbols for use on
equipment (IEC 60416:1988)
ETS 300 158 1992 Satellite Earth Stations and Systems (SES) - Television Receive
Only (TVRO-FSS) Satellite Earth Stations operating in the
11/12 GHz FSS bands
ETS 300 249 1993 Satellite Earth Stations and Systems (SES) - Television Receive
Only (TVRO) equipment used in the Broadcasting Satellite Service
(BSS)
ETS 300 457 1995 Satellite Earth Stations and Systems (SES) - Test methods for
Television Receive Only (TVRO) operating in the 11/12 GHz
frequency bands
IEC 60169-8 1978 Radio frequency connectors -- Part 8: RF coaxial connectors with
inner diameter of outer conductor 6,5 mm (0,25 in) with bayonet
lock - Characteristic impedance 50 ohms (type BNC)
CCIR Rec. 468 Measurement of audio frequency noise in broadcasting and in
sound recording systems
ITU-T Rec. J.61 06/90 Transmission performance of television circuits designed
for use in international connections
(Formerly ITU-R Rec. 567-3)
ITU-T Rec. J.101 06/90 Measurement methods and test procedures for teletext signals
(Formerly ITU-R Rec. 720)
CCIR Report 624 Characteristics of television systems
3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
For the purposes of this standard, the following definitions apply.
3.1.1
headend
equipment which is connected between receiving antennas or other signal sources and the
remainder of the cable network, to process the signals to be distributed.
NOTE  The headend may, for example, comprise antenna amplifiers, frequency converters, combiners, separators
and generators.
3.1.2
hub headend
a headend used to feed the entire operating network in the service area
3.1.3
local headend
a headend which is directly connected to the system trunk feeders or to a short haul "trunk
feeder replacement" link
3.1.4
remote headend
a headend from which signals are delivered to a local headend via a long-distance
terrestrial link
- 9 - EN 50083-5: 2001
3.1.5
MATV headend
a headend used in blocks of flats and in built-up sites to feed TV channels and FM radio
channels into the house network or the spur network.=
3.1.6
Satellite Master Antenna Television system (SMATV)
a system which is designed to provide sound and television signals to the households of a
building or group of buildings. Two system configurations are defined in EN 300 473 as
follows:
• SMATV system A, based on transparent transmodulation of QPSK satellite signals into
QAM signals to be distributed to the user
• SMATV system B, based on direct distribution of QPSK signals to the user, with two
options:
- SMATV-IF distribution in the satellite IF band (above 950 MHz)
- SMATV-S distribution in the VHF/UHF band, for example in the extended
S-band (230-470 MHz)
3.1.7
headend for individual reception
a headend supplying an individual household. This type of installation may include one or
more system outlets
3.1.8
antenna preamplifier
an amplifier (often a low noise type) associated with an antenna
3.1.9
frequency converter
a device for changing the carrier frequency of one or more signals
3.1.10
combiner
a device in which the signals arriving at two or more input ports are fed to a single output
port
NOTE  Some forms of this device may be used in the reverse direction as splitters.
3.1.11
decibel ratio
ten times the logarithm of the ratio of two quantities of power P to P i. e.
1 2
,
P
10lg (dB)
P
3.1.12
standard reference power and voltage
in cable networks the standard reference power P is 1/75 pW
NOTE  This is the power dissipated in a 75 Ohm resistor with a voltage drop of 1µV across it.
RMS
The standard reference voltage U is 1 µV.
3.1.13
level
the level of any power P is the decibel ratio of that power to the standard reference power
P , i.e.
P
10lg
P
The level of any voltage U is the decibel ratio of that voltage to the standard reference
voltage U , i.e.
U
20lg
U
This may be expressed in decibels (relative to 1 µV in 75 Ω) or more simply in dB(µV) if
there is no risk of ambiguity.
3.1.14
image carrier power
"power", in relation to a vision-modulated carrier, is defined as the power at the peak of the
modulation envelope (i.e. the maximum RMS voltage squared, divided by the resistance)
3.1.15
attenuation
the ratio of the input power to the output power of an equipment or a system, usually
expressed in decibel
3.1.16
gain
the ratio of the output power to the input power of any equipment or system, usually
expressed in decibel
3.1.17
automatic gain control (AGC)
the automatic control of a device to maintain the level of the signal at its output constant,
using the signal to be controlled as the control stimulus
3.1.18
amplitude frequency response
the gain or losses of an equipment or system plotted against frequency
3.1.19
intermodulation
the process whereby the non-linearity of equipment in a system produces spurious output
signals (called intermodulation products) at frequencies which are linear combinations of
those of the input signals
3.1.20
carrier-to-intermodulation ratio
the difference in decibels between the carrier level at a specified point in a system or in an
equipment and the level of a specified intermodulation product or combination of products

- 11 - EN 50083-5: 2001
3.1.21
carrier-to-noise ratio
the difference in decibels between the vision or sound carrier level at a given point in the
system and the noise level at that point (measured within a bandwidth appropriate to the
television or radio system in use)
3.1.22
well-matched
the matching condition when the return loss of the equipment complies with the
requirements of Table 1 of EN 50083-3
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.
3.1.23
subscriber equipment
equipment at the subscriber premises such as receivers, tuners, decoders, video recorders
3.1.24
out of band emissions
emissions on a frequency or on frequencies immediately outside the necessary bandwidth
which results from the modulation process, but excluding spurious emissions
3.1.25
spurious emissions
emissions on a frequency or frequencies which are outside the necessary bandwidth and
the level of which may be reduced without affecting the corresponding transmission of
information. Spurious emissions include harmonic emissions, parasitic emissions,
intermodulation products and frequency conversion products but exclude out of band
emissions
3.1.26
unwanted emissions
consist of spurious emissions and out of band emissions
3.2 Symbols
Symbols Terms Symbols Terms
voltmeter amperemeter
V A
variable Generator variable attenuator
G
dB
Device under Test oscilloscope
DUT
high pass filter low pass filter

Symbols Terms Symbols Terms
frequency converter amplifier
f
f
splitter
pilotgenerator
modulator demodulator
adjustable AC voltage source detector with LF-amplifier

ground variable resistor
3.3 Abbreviation
AC alternating current
AF audio frequency
AGC automatic gain control
ALC automatic level control
AM amplitude modulation
BSS broadcast satellite services
CATV community antenna television (system)
CH channel
C/N carrier to noise (ratio)
CW continuous wave
DAB digital audio broadcasting
DG peak-to-peak differential gain
PP
DPH peak-to-peak differential phase
PP
DSR digital satellite radio
DUT device under test
EMC electromagnetic compatibility
FM frequency modulation
FSS fixed satellite services
HP high pass
IF intermediate frequency
IP international protection
ITS interval test signal
LF low frequency
- 13 - EN 50083-5: 2001
LNC low noise converter
LP low pass
LUM NL luminance non-linearity
MATV master antenna television (system)
MPEG motion picture experts group
MTBF meantime between failure
NICAM near-instantaneously companded audio multiplex
NF noise figure
PAL phase alternating line
QAM quadrature amplitude modulation
Q grade(s) quality grade(s)
QPSK quadrature phase shift keying
RF radio frequency
RMS root mean square
SAT IF (1st) satellite intermediate frequency
SECAM Séquenciel couleur a mémoire
SMATV satellite master antenna television (system)
S/N signal to noise (ratio)
TV television
TVRO television receive only (system, .)
UHF ultra high frequency
VHF very high frequency
VSB-IF vestigial sideband intermediate frequency

NOTE  Only the abbreviations used in the English version of this part of EN 50083 are mentioned in this subclause.
The German and the French versions of this part may use other abbreviations. Refer to 3.3 of each language version
for details.
4 Methods of measurement
4.1 Single-channel intermodulation
Specifications for channel amplifier / frequency converter
Frequencies and levels of test carriers as shown in Figure 3 simulate a colour television
transmission where f , f and f respectively correspond to vision carrier, colour subcarrier and
a b c
sound carrier. The most significant intermodulation products are:
P3 = f + f - f
f a b c
P3 = f + f - f
g a c b
The carrier levels for different television systems are given in Table 1.

Table 1 - Test signal levels in decibels relative to reference level
System B, G, H, I L
Test signal
Vision carrier (f)-8 0
a
Colour subcarrier (f)-17 0
b
Sound carrier (f)-10 0
c
Reference level
f f f
Fundamental
a b c
P3 P3
third order f g
Figure 3 - Frequencies and levels of test carriers
NOTE  Levels of measuring signals are to be adjusted as in Table 1.
4.2 Three-carrier intermodulation measurement
Specifications for the measurement of three-carrier intermodulation on sub-band, full-band and
multi-band amplifiers or multi channel frequency converters
In television band amplifiers the simultaneous transmission of multi channel programming may
cause mutual interference between vision carriers through crossmodulation. The carrier-to-
crossmodulation distortion ratio is defined as the difference between the level of a given test
carrier and the level of the crossmodulation products produced by interfering signals and falling
near that test carrier.
This method of measurement is used to simulate transfer of modulation between two television
signals. The test carrier having the frequency f is an unmodulated wanted signal, while the
a
carriers having the frequencies f and f represent the sidebands of a one-hundred percent
b c
amplitude modulated (AM) interfering signal (Table 2 and Figure 4).
Carrier-to-interfer-
ence ratio
- 15 - EN 50083-5: 2001
Table 2 - Test signal levels in decibels relative to reference level
Test signal
Test frequency (f)0
a
Interfering frequency (f)-6
b
Interfering frequency (f)-6
c
Reference level
f f f
a b c
f -2 MHz f +2 MHz
a a
2 MHz
Figure 4 - Test carrier and interfering products in the passband
The carriers having the frequencies f , f and f shall be varied over the entire frequency range.
a b c
NOTE  If the equal carrier method of measurement as described in subclauses 4.2.2 and 5.11.2 of EN 50083-3 is
used, the output level giving the appropriate signal-to-distortion ratio must be increased by 6 dB.
4.3 Two carrier intermodulation measurements for second and third order
products
The two carrier method is applicable to the measurement of the ratio of the carrier to a single
intermodulation product at a specified point within a cable network. The method can also be
used to determine the intermodulation performance of individual items of equipment.
Second-order products are encountered only in wideband equipment and systems covering
more than one octave, and can be measured using two signals.
Third-order products are encountered in both wideband and narrow-band equipment and
systems and, depending on the type, can also be measured using two signals.
Carrier-to-
interference
ratio
Intermodulation products with test signals at frequencies f and f (Figure 5)
a b
Second order (see note): P2 = f - f
a b a
P2 = f + f
b a b
Third order: P3 =2f - f where 2f > f
a a b a b
P3 = f - 2f where 2f < f
a b a a b
P3 =2f - f
b b a
P3 =2f + f
c a b
P3 =2f + f
d b a
NOTE : Not applicable to narrow band equipment unless the frequency range covered by the equipment is such
that 2f < f .
min max
Signal levels
The two test carriers shall be set to the reference level.
Reference level
f f
Fundamental
a b
P2
P2
b
Second order a
P3
P3 b P3 P3
Third order a c d
Figure 5 - An example showing products formed when 2f > f
a b
NOTE  The sequence of the intermodulation products will depend on the fundamental frequency chosen.
4.4 Carrier-to-spurious signal ratio at the output
4.4.1 Carrier-to-spurious signal ratio at the output of equipment for AM-TV systems
Carrier-to-spurious signal ratio in the output, out of channel 40 . 862 MHz
The carrier levels are given in Table 3.

- 17 - EN 50083-5: 2001
Table 3 - Test signal levels in decibels relative to reference level
System B/G/I L
Test signal
Vision carrier (f)0 0
a
Sound carrier (f)-10 0
b
Reference level
> 60 dB
CH-1 CH CH+1
f f
a b
f f
u w
f f
x y
f = 2f - f ; f = 2f - f
x a b y b a
f ,f are examples for all other spurious outputs
u w
NOTE: for exception: If for channel processing in CH-1 and CH+1
the difference between the intermodulation products fx and fy and
the reference level is less than 60 dB, the device shall be marked
with the note:
*Not suitable for adjacent channel operation
Figure 6 - Carrier-to-spurious signal ratio in the output
4.4.2 Carrier-to-spurious signal ratio at the output of equipment for FM-TV systems
Carrier-to-spurious signal ratio at the output of equipment for FM-TV systems, out of channels
and in channels between 950 MHz and 3 000 MHz.

Reference level
≥ 35 dB
CH-n CH-1 CH CH+1 CH+m
f f
x b
f f f
z y a
Figure 7 - Carrier-to spurious signal ratio at the output
f , f and f are intermodulation products between f and f or with other signals occuring in the
x y z a b
system like oscillator frequency signals. f is varied within the whole transmission range
b
assigned to the device except for the useful channel regarded.
4.5 Television carrier-to-noise ratio
4.5.1 Introduction
The method described is applicable to the measurement of the carrier-to-random-noise ratio
within a television channel at a specified point within a cable network. The method of
measurement actually determines carrier (plus noise) to noise ratio; however, the difference
between this and the carrier-to-noise ratio is very small if the value exceeds 20 dB.
The method assumes that the random noise is evenly distributed within the channel.
Equipment required:
• a selective voltmeter with a known noise bandwidth less than that of the channel to be
measured;
• a CW signal generator covering the frequencies at which the tests are to be carried out;
• a variable attenuator with a range greater than the carrier-to-noise ratio expected;
• a shielded terminating resistor.
NOTE  Additional items may be necessary, for example, to ensure correct calibration and operation of the test
equipment (see 4.5.3).
Connection of the equipment:
The equipment shall be connected as in Figure 8.

- 19 - EN 50083-5: 2001
Meter Attenuator
preamplifier and filter
Signal
DUT dB dB
generator
Variable
Selective
attenuator
voltmeter
Shielded
terminating
resistor
Measuring equipment
Pilot signal
generator
NOTE: Dotted lines signify items wich may may be required
Figure 8 - Arrangement of test equipment for carrier-to-noise ratio measurement
4.5.2 Measurement procedure
4.5.2.1 General
The test set-up shall be well-matched and the sensitivity of the measuring equipment (see 4.5.3.4) shall be
known over the frequency range of the channel to be measured.
Where the system to be measured includes automatic gain control (AGC), tests shall be carried out at
minimum and maximum levels of signal input.
Where the system to be measured includes automatic level control (ALC), pilot signals of the correct type,
frequency and level shall be maintained throughout the tests.
4.5.2.2 Calibration
The selective voltmeter shall be calibrated and checked for satisfactory operation as follows:
• level correction, average/RMS or peak/RMS (see 4.5.3.3);
• noise bandwidth (see 4.5.3.5).
4.5.2.3 Other checks
• sensitivity (see 4.5.3);
• noise (see 4.5.3.4.1);
• intermodulation (see 4.5.3.4.2);
• overload (see 4.5.3.4.3).
4.5.2.4 Measurement
Set the signal generator to the vision carrier frequency of the channel to be tested and adjust its
output, and those of the different points of the system as far as the point of measurement, to
obtain the specified system operating levels throughout.

Connect the variable attenuator and selective voltmeter (and other items if required see 4.5.3) to
the point of measurement. Tune the voltmeter to the reference signal and note the attenuator
value a required to obtain a convenient voltmeter reading R. The attenuator value a should be
1 1
slightly greater than the signal-to-noise ratio expected at the point of measurement.
Disconnect the generator and replace it by the shielded terminating resistor, or, if the reference
signal is used for AGC, retune the voltmeter within the channel such that it is influenced only by
random noise. Reduce the attenuator setting to the value a required to again obtain the same
voltmeter reading R.
The carrier-to-noise ratio in decibel is given by:
C/N = a - a - C - C
1 2 m b
where:
a = attenuator value for the reference signal
a = attenuator value for the noise
C = voltmeter level correction factor (see 4.5.3.3.1)
m
C = bandwidth correction factor (see 4.5.3.3.2)
b
4.5.3 Equipment required -- additional items
4.5.3.1 Voltmeter preamplifier
If the sensitivity of the selective voltmeter is not adequate for the levels of noise expected at the
point of measurement, a suitable preamplifier of the correct input impedance and sensibly flat
response over the channel to be measured will be necessary. This preamplifier should be
included as part of the measuring equipment when making the checks described in 4.5.3.4.
4.5.3.2 Voltmeter input filter
If the selectivity of the selective voltmeter is not adequate to reduce to an insignificant level the
effects of "out-of-channel" signals on the measurement of the noise voltage, a suitable filter
having a sensibly flat response over the channel to be measured will be required as shown in
Figure 8.
In this case, it is important that the matching between the filter and the preceding equipment
shall be such that it results in a return loss of not less than 20 dB within the frequency range of
the channel to be measured, and that the whole measuring equipment shall satisfy all the
requirements of 4.5.3.4.
Where this is in doubt, an attenuator of sufficient value to satisfy this requirement should be
included as shown in Figure 8.
4.5.3.3 Correction factors
4.5.3.3.1 Level correction factor C
m
If a selective voltmeter responding to the average value of the applied voltage but calibrated in
RMS values (assuming a sinusoidal input signal) is employed, it will indicate a level
approximately 1 dB below the RMS value of the applied noise voltage in its noise bandwidth. In
this instance C may be taken as 1 dB.
m
If a selective voltmeter of the peak reading type is used, a correction appropriate to the
particular instrument shall be employed as C .
m
- 21 - EN 50083-5: 2001
4.5.3.3.2 Bandwidth correction factor C
b
This correction factor takes into account the difference between the noise bandwidth of the
selective voltmeter B and that of the appropriate television system B .
m TV
B
TV
C = 10lg (dB)
b
B
m
4.5.3.3.3 Noise bandwidth B
TV
The noise bandwidth B for various television systems is given in Table 4:
TV
Table 4- Noise bandwidth
System I B,G L
B (MHz) 5,08 4,75 5,58
TV
The values in Table 4 shall be used when determining C (see 4.5.3.3.2).
b
4.5.3.4 Preliminary checks on the measuring equipment for carrier-to-noise ratio
4.5.3.4.1 Noise
With the input to the measuring equipment terminated and the variable attenuator set to zero,
tune the voltmeter over the frequency range of interest and check that the reading remains
negligible relative to that expected when measuring the system noise.
4.5.3.4.2 Intermodulation
Connect signals, corresponding to those which will be present at the point of measurement, via
a matched directional coupler, to the measuring equipment. Tune the meter to any significant
intermodulation product and note the lowest value of the signal/intermodulation ratio within the
channel being considered. This ratio should exceed the minimum carrier-to-noise ratio expected
at the point of measurement by an amount relevant to the accuracy desired. For example, 20 dB
would result in an error of less than 1 dB.
If this requirement is not met, an appropriate channel pass-band filter to attenuate one of the
signals should be included as indicated in Figure 8, and the checks of 4.5.3.4.1 and 4.5.3.4.2
should be repeated.
NOTE  This check relating to intermodulation is necessary only if automatic level control (ALC) pilot signals or other
signals are present during the carrier-to-noise ratio tests.
4.5.3.4.3 Overload
Connect signals as in 4.5.3.4.2 and attenuate one of them to a level comparable with that of the
noise voltage expected at the point of measurement. Tune the meter to the low level signal.
Tune the low level signal and the meter in step over the frequency range of the channel to be
measured and check that the meter reading does not change when the high level signals are
switched off and on.
If this requirement is not met, a filter to attenuate one or more of the signals should be included
as indicated in Figure 8 and all the above checks should be repeated as mentioned in 4.5.3.4.2.

4.5.3.5 Calibration of the selective voltmeter
Noise bandwidth (B )
m
A well-matched noise generator is required, having a known bandwidth B (see note 1), and an
g
output voltage of known RMS value U sufficient to give a convenient reading on the voltmeter.
g
The voltmeter is connected to the noise generator (see note 2) and tuned to a test frequency.
The true RMS voltage U is measured (see 4.5.3.3). This procedure is repeated at each test
m
frequency.
The noise bandwidth of the voltmeter (B ) is given by:
m
B = B (U /U )
m g m g
where B and B are in the same units, for example megahertz, and U and U are in the same
m g m g
units, for example microvolts.
NOTE 1  B will usually be taken as 1 MHz and U is calculated for this bandwidth from information provided by the
g g
manufacturer of the noise generator.
NOTE 2  The noise generator may consist of a noise diode source followed by an appropriate amplifier.
4.6 Differential gain and phase for PAL/SECAM signals
Introduction
The methods described are applicable to the measurement of differential gain and differential
phase for complete systems and items of equipment thereof. The test signals employed are in
both cases those recommended in ITU-T Recommendation J.61, and are shown in Figure 10
and Figure 11. The definitions are also those given in the same recommendation.
It is intended that these measurements be carried out with test signals inserted at the system
headend. They may be either of the full field type or, where convenient, may be inserted in the
field blanking period.
The use of frame inserted test signals available on the broadcast TV channels is not generally
recommended as these are subject to variations beyond the control of the user. However, where
such signals of known stability and of adequate quality are available, they may be used to carry
out these measurements.
4.6.1 Differential gain (for PAL/SECAM only)
Definition
Differential gain is expressed by two values: x%, and y%, which represent the two peak
amplitudes of the sub-carrier relative to the amplitude of the sub-carrier at blanking level. In the
case of a monotonic characteristic, either x or y will be zero.
Differential gain, in percentage referred to blanking level, can be found from the expressions
below:
AA− AA−
min 0 min 0
x = ⋅100% y = ⋅100%
A A
0 0
Peak-to-peak differential gain (DG ) can be found from the expression:
pp
AA−
max min
DG = ⋅100%
PP
A
where:
A = amplitude of the received sub-carrier at blanking level
A = amplitude of the sub-carrier on one of the other treads of the staircase.

- 23 - EN 50083-5: 2001
4.6.1.1 Equipment required
The test set-up shall be well-matched.
• An oscilloscope which will not contribute significant distortion to the signal displayed.
• A modulator (unless transmitted test signals in the field blanking interval are to be used)
having the following characteristics:
- radio-frequency characteristics (excluding sound) corresponding to CCIR Report 624,
and appropriate to the television transmission system used;
- video signal input requirement of 1 V peak-to-peak composite;
- a modulated output signal of a convenient amplitude.
• A demodulator having characteristics appropriate to the television transmission system used.
• Two attenuators variable in steps of not more than 1 dB.
• A band-pass filter with f = 4,43 MHz and a bandwidth of 0,5 MHz.
• A test signal generator providing signals having characteristics appropriate to the television
transmission system under consideration, as specified in ITU-T Recommendation J.61
(Signal D2) (see Figure 10).
NOTE  Most commercially available test signal generators will provide this signal as part of a composite test line.
4.6.1.2 Connection of the equipment
The equipment shall be connected as in Figure 9.
4.6.1.3 Measurement procedure
With point A directly connected to point B (see Figure 9), adjust attenuator A for an output level
sufficient to drive the system to be tested and attenuator A to obtain the correct input level to
the demodulator.
Insert the appropriate band-pass filter after the demodulator (see Figure 9) and measure the
differential gain by examining the modified staircase waveform (see Figure 11 and subclause
4.6.1).
Ensure that the distortion of the test signal caused by the control loop (test equipment) is small
compared with the maximum distortion allowed for the system or equipment to be tested.
NOTE  Where the linearity of the modulator/demodulator is such that on systems B and G (10% residual carrier) this
requirement cannot be met, it will be necessary either to reduce the sub-carrier amplitude or to ignore the sixth
(uppermost) tread.
Connect the system or equipment to be tested between points A and B, and disconnect the
band-pass filter. Adjust attenuator A to return the input level to the demodulator to that used
mentioned above.
Reinsert the band-pass filter and measure the maximum differential gain by examining the
modified staircase waveform (see also Figure 11 and subclause 4.6.1).
NOTE  This figure includes the distortion due to the test equipment as well as the system or equipment under test.
4.6.2 Differential phase
Definition
Differential phase is expressed by two values: x, and y, in degrees, which represent the two
peak phases of the sub-carrier relative to the phase of the sub-carrier at blanking level. In the
case of a monotonic characteristic, both x and y will be zero.

Differential phase, in degrees, referred to blanking level, can be found from the expressions
below:
x=−ϕϕ y=−ϕϕ
max 0 max 0
Peak-to-peak differential phase (DPH ) can be found from the expression:
pp
DPH=−ϕϕ ()°
PP max min
where:
ϕ = phase of the received sub-carrier at blanking level
ϕ = phase of the sub-carrier on one of the other treads of the staircase.
4.6.2.1 Equipment required
• A modulator (unless transmitted test signals in the field blanking interval are to be used)
having the following characteristics:
- radio-frequency characteristics (excluding sound) corresponding to CCIR Report 624,
and appropriate to the television transmission system used;
- video signal input requirement of 1 V peak-to-peak composite;
- a modulated output signal of a convenient amplitude.
• A demodulator having characteristics appropriate to the television transmission system used.
• Two attenuators variable in steps of not more than 1 dB.
• A test set capable of measuring the difference in phase of the sub-carrier at each tread of
the staircase, with reference to the blanking level.
• A test waveform generator (unless transmitted test signals in the field blanking intervals are
to be used) providing signals having characteristics appropriate to the television transmission
system under consideration, as spec
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