EN 60510-3-4:1994
(Main)Methods of measurement for radio equipment used in satellite earth stations - Part 3: Methods of measurement on combinations of sub-systems - Section 4: Measurements for frequency division multiplex (f.d.m.) transmission
Methods of measurement for radio equipment used in satellite earth stations - Part 3: Methods of measurement on combinations of sub-systems - Section 4: Measurements for frequency division multiplex (f.d.m.) transmission
This section deals with baseband-to-baseband measurements for frequency division multiplex (f.d.m.) telephony. These measurements are additional to those given in part 1, section four of this publication, which are common to telephony and to television, for example group-delay and amplitude/frequency characteristics.
Meßverfahren für Funkgerät in Satelliten-Erdfunkstellen - Teil 3: Meßverfahren für Kombinationen von Untersystemen - Hauptabschnitt 4: Messungen der Frequenzmultiplex (FDM)-Übertragung
Méthodes de mesure pour les équipements radioélectriques utilisés dans les stations terriennes de télécommunication par satellites - Partie 3: Méthodes de mesure applicables aux combinaisons de sous-ensembles - Section 4: Mesures pour la transmission de la téléphonie multivoie à multiplexage par répartition en fréquence (m.r.f.)
Traite des mesures entre accès en bande de base pour la transmission de la téléphonie multivoie à multiplexage par répartition en fréquence (m.r.f.). Ces mesures viennent en complément de celles décrites dans la partie 1, section 4, qui sont communes à la téléphonie et à la télévision, comme par exemple, la mesure de la caractéristique de temps de propagation de groupe ou celle de la caractéristique amplitude/fréquence.
Methods of measurement for radio equipment used in satellite earth stations - Part 3: Methods of measurement on combinations of sub-systems - Section 4: Measurements for frequency division multiplex (f.d.m.) transmission
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2002
Methods of measurement for radio equipment used in satellite earth stations - Part
3: Methods of measurement on combinations of sub-systems - Section 4:
Measurements for frequency division multiplex (f.d.m.) transmission
Methods of measurement for radio equipment used in satellite earth stations -- Part 3:
Methods of measurement on combinations of sub-systems -- Section 4: Measurements
for frequency division multiplex (f.d.m.) transmission
Meßverfahren für Funkgerät in Satelliten-Erdfunkstellen -- Teil 3: Meßverfahren für
Kombinationen von Untersystemen -- Hauptabschnitt 4: Messungen der
Frequenzmultiplex (FDM)-Übertragung
Méthodes de mesure pour les équipements radioélectriques utilisés dans les stations
terriennes de télécommunication par satellites -- Partie 3: Méthodes de mesure
applicables aux combinaisons de sous-ensembles -- Section 4: Mesures pour la
transmission de la téléphonie multivoie à multiplexage par répartition en fréquence
(m.r.f.)
Ta slovenski standard je istoveten z: EN 60510-3-4:1994
ICS:
33.060.30 Radiorelejni in fiksni satelitski Radio relay and fixed satellite
komunikacijski sistemi communications systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
NORME CEI
INTERNATIONALE IEC
60510-3-4
INTERNATIONAL
Première édition
STANDARD
First edition
1992-05
Méthodes de mesure pour les équipements
radioélectriques utilisés dans les stations
terriennes de télécommunication par satellites
Troisième partie: Méthodes de mesure
applicables aux combinaisons de sous-ensembles
Section quatre — Mesures pour la transmission
de la téléphonie multivoie à multiplexage
par répartition en fréquence (m. r.f. )
Methods of measurements for radio equipment
used in satellite earth stations
Part 3: Methods of measurement for
combinations of sub -systems
Section Four — Measurements for frequency
division multiplex (f.d.m.) transmission
© IEC 1992 Droits de reproduction réservés — Copyright - all rights reserved
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510-3-4 ©IEC – 3 –
CONTENTS
Page
FOREWORD 5
Clause
1 Scope 7
2 Noise-loading pe rformance 7
3 Continuity pilot and out-of-band noise (o.b.n.) 23
4 Periodic noise 27
5 Intelligible crosstalk 27
6 References 31
7 Bibliography 31
Figures 33
Appendix A – Conversion of the measured n.p.r. to noise power level or signal-to-noise ratio. 41
510-3-4© IEC - 5 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
METHODS OF MEASUREMENT FOR RADIO EQUIPMENT
USED IN SATELLITE EARTH STATIONS
Part 3: Methods of measurement on combinations of
sub-systems
Section four: Measurements for frequency division multiplex
(f.d.m.) transmission
FOREWORD
1) The formal decisions or agreements of the IEC 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.
They have the form of recommendations for international use and they are accepted by the National
2)
Committees in that sense.
In order to promote international unification, the IEC expresses the wish that all National Committees
3)
should adopt the text of the IEC recommendation for their national rules in so far as national conditions will
permit. Any divergence between the IEC recommendation and the corresponding national rules should, as
far as possible, be clearly indicated in the latter.
This standard has been prepared by Sub-Committee 12E: Radio relay and fixed-satellite
communications systems, of IEC Technical Committee No. 12: Radiocommunications.
The text of this standard is based on the following documents:
Report on Voting
Six Months' Rule
12 E(CO)128
12E(CO)120
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 IEC publications are quoted in this standard:
Publications Nos. 50(55) (1987): International Electrotechnical Vocabulary (IEV) - Chapter 55: Telegraphy
and telephony.
510-1-4(1986): Methods of measurement for radio equipment used in satellite earth stations -
Part 1: Measurements common to sub-systems and combinations of sub-
systems - Section four: Measurements in the baseband.
510-3-4©IEC -7-
METHODS OF MEASUREMENT FOR RADIO EQUIPMENT
USED IN SATELLITE EARTH STATIONS
Part 3: Methods of measurement on combinations of
sub-systems
Section four: Measurements for frequency division multiplex
(f.d.m.) transmission
1 Scope
This section deals with baseband-to-baseband measurements for frequency division
multiplex (f.d.m) telephony. These measurements are additional to those already given
in part 1, section four of this publication: Measurements in the baseband, which are
common to telephony and to television, for example group-delay and amplitude/frequency
characteristics.
All of the following measurements are carried out on a system loop either by establishing
a transmission path through the transmitting and receiving chain via a test loop translater
or by means of an i.f. loop.
2 Noise-loading performance
2.1 Definitions and general considerations
The noise-loading pe rformance of a system is the noise power measured in a chosen
narrow measuring channel, which simulates an unloaded telephone channel, when the
baseband is loaded with random noise of uniform spectrum (white noise) at a conventional
loading level (see 2.1.1). The white noise applied to the baseband input of the system
under test is limited to the frequency band occupied by the telephone channels by means
of a high-pass and a low-pass filter. Noise-measuring channels are provided by means of
narrow band-stop filters which allow performance to be measured at several frequencies
including channels located close to the bottom, middle and top of the baseband, frequency
range.
The total noise appearing within a noise-measuring channel at the system output com-
prises basic noise and intermodulation noise (sometimes referred to as "idle noise" and
"distortion noise" respectively). It is, therefore, common practice to measure the noise
within each noise-measuring channel with the baseband loaded with noise and then un-
loaded, in order to obtain the total noise and basic noise separately; from these results the
intermodulation noise may be obtained.
The noise pe rformance may be expressed as a noise power ratio (n.p.r.), a signal-to-noise
ratio, in units of noise power or noise power level referred to the system zero relative level
point. The units used may be picowatts, decibels above 1 pW or decibels below 1 mW,
and they may be specified as a weighted or unweighted psophometric value.
510-3-4 ©I EC - 9 -
Noise power ratio is defined as the ratio of the noise power in a measuring channel when
the baseband is fully loaded with the white noise load, to the power in that channel either
with all the baseband loaded except the measuring channel (i.e. total noise) or with all the
baseband unloaded (i.e. basic noise); n.p.r. is always expressed as a positive number
of decibels.
Signal-to-noise ratio is defined as the ratio of the power of the standard test tone (0 dBmO)
to the noise power, in a specified bandwidth within the noise-measuring channel, both
being referred to the same point in the circuit. Signal-to-noise ratio may be measured
weighted or unweighted and is expressed as a positive number in decibels.
Conversion between commonly encountered noise-loading measurement units may be
made by reference to appendix A.
2.1.1 Conventional load
The conventional loading level, which is defined by the CCITT (reference 1, see clause 6)
and recommended by the CCIR (reference 2, see clause 6), is shown in table 1 for some
Lc of the
typical channel capacities. For other channel capacities the mean power level
conventional load may be calculated from the following expressions:
(2-1)
15 + 10 log 10 N dBmO for N >_ 240 Lc = -
for 12 <_ N < 240 (2-2)
Lc = - 1 + 4 N dBmO
Iog10
where N is the system channel capacity.
Notes
1 These levels simulate the mean power of speech plus signalling currents, etc., transmitted over the
system during the busy hour. Where a significant proportion of the baseband is used for v.f. telegraphy or
data transmission, these expressions do not apply.
60. For smaller channel
2 Equations 2-1 and 2-2 give a good approximation to actual signals when N >_
capacities, however, tests with white noise are less realistic owing to the differing nature of actual signals
and test signals.
—11 —
510-3-4 © IEC
Table 1 — Level of the conventional load
Level of the conventional
Number of telephone
load
channels
(dBmO)
+4,5
+5,2
60 +6,1
+6,4
+6,9
132 +7,5
+8,1
+9,1
312 +9,9
+10,7
+11,4
+11,9
+12,4
612 +12,9
792 +14,0
972 +14,9
+15,4
1 092
1 872 +17,7
A conventionally loaded system is one which is loaded at the conventional loading level
with a uniform spectrum random noise signal which is band-limited to correspond with the
total bandwidth of the f.d.m. signal.
The test signal level, in most cases, is chosen to equal the conventional load.
2.1.2 Noise components
The total noise measured within the baseband of a simulated satellite system includes the
following three components:
Residual noise which is independent of path attenuation and loading. This is
a)
normally referred to as path-loss-independent basic noise.
Thermal noise which varies with path attenuation. This is normally referred to as
b)
path-loss-dependent basic noise.
Intermodulation noise which is dependent upon the baseband noise loading level.
c)
Basic noise a) + b) is measured without noise loading as described below in 2.3.4. Total
noise a) + b) + c) is measured with noise loading as described below in 2.3.2 or 2.3.3.
2.2 Measuring equipment
2.2.1 General considerations
Equipment for the measurement of noise-loading performance is commercially available
and known either as "white noise test sets" or "noise-loading test sets". A white noise test
set comprises a noise generator and a noise receiver; a typical circuit arrangement is
shown in figure 1.
510-3-4 © IEC — 13 —
To ensure test equipment compatibility and to achieve good measurement accuracy, the
relevant characteristics of white noise test sets are closely specified by both CCIR
(reference 2, see clause 6) and the CCITT (reference 3, see clause 6).
Commercial white noise test sets are normally sufficiently accurate for measurements on
simulated satellite systems without making allowance for test equipment errors. However,
where the required accuracy of measurement is comparable with the intrinsic accuracy of
the test equipment, due allowance for measurement error should be made in the
presentation of results.
Measurement accuracy depends upon many factors, including the following:
— generator and receiver attenuator and monitor accuracies;
number of band-stop filters inserted and the effective bandwidths of the
—
noise-measuring channels;
region of the loading curve at which the measurement is being made (i.e. whether
—
basic or intermodulation noise predominates);
— order of distortion predominant in the system under test.
These factors are discussed in references 3 and 4 (see 6) and in the publications listed in
the bibliography (see 7).
2.2.2 Noise generator
2.2.2.1 Output characteristics
The r.m.s. voltage of the noise source, when measured in a bandwidth of about 2 kHz,
shall not vary by more than ± 0,5 dB within the bandwidth corresponding to the baseband
of the system under test.
The test signal should have a Gaussian amplitude distribution up to a peak-to-r.m.s. ratio
of at least 12 dB. The density of the noise power at the generator output shall have a
maximum value of not less than —40 dBm/kHz to enable loading levels up to at least 10 dB
above the conventional loading level to be used. The transmit level should be adjustable
continuously or in small steps (e.g. 0,1 dB), by means of an output attenuator, to the
specified value. The attenuator may typically have a range in excess of 50 dB.
Band-limiting and band-stop filters
2.2.2.2
High-pass and low-pass filters are required to define the baseband frequency limits
appropriate to the simulated system under test and a series of band-stop filters are
required to determine the noise-measuring channels. A wide variety of filters is available
with current white noise test sets so enabling tests to be carried out for all commonly
encountered telephone channel capacities. The recommended filter frequencies are listed
in table 2 and detailed filter specifications are given in reference 2 (see clause 6).
510-3-4 © I EC
- 15 -
Table 2 - Recommended filter frequencies
(from reference 2, see clause 6)
Effective cut-off frequencies
Limits of band
of band-limiting filters
occupied by Frequencies of recommended
Capacity
(kHz)
measuring channels
telephone
(channels)(
channels (kHz)
High pass Low pass
(kHz)
12- 60 12 ± 0,5 60 ±0,5 16 56
24 12- 108 12 ± 0,5
108 ± 1,0 16 98
36 12- 156 12 ± 0,5 156 ± 1,0
16 140
48 12-
...
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