SIST EN 60835-3-10:2002

SLOVENSKI STANDARD
01-oktober-2002
Methods of measurement for equipment used in digital microwave radio
transmission systems - Part 3: Measurements on satellite earth stations - Section
10: Terminal equipment - TDMA traffic earth stations (IEC 60835-3-10:1994)
Methods of measurement for equipment used in digital microwave radio transmission
systems -- Part 3: Measurements on satellite earth stations -- Section 10: Terminal
equipment - TDMA traffic earth stations
Meßverfahren für Geräte in digitalen Mikrowellen-Funkübertragungssystemen -- Teil 3:
Messungen an Satelliten-Erdfunkstellen -- Hauptabschnitt 10: Endeinrichtungen-
Erdfunkstelle für TDMA-Betrieb
Méthodes de mesure applicables au matériel utilisé pour les systèmes de transmission
numérique en hyperfréquence -- Partie 3: Mesures applicables aux stations terriennes de
télécommunications par satellite -- Section 10: Equipement terminal - Station terrienne
de trafic AMRT
Ta slovenski standard je istoveten z: EN 60835-3-10:1994
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
INTERNATIONAL 60835-3-10
Première édition
STANDARD
First edition
1994-07
Méthodes de mesure applicables au matériel
utilisé pour les systèmes de transmission
numérique en hyperfréquence
Partie 3:
Mesures applicables aux stations terriennes
de télécommunications par satellite
Section 10: Equipement terminal —
Station terrienne de trafic AMRT
Methods of measurement for equipment used in
digital microwave radio transmission systems
Part 3:
Measurements on satellite earth stations
Section 10: Terminal equipment —
TDMA traffic earth station
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835-3-10 © IEC:1994 - 3 -
CONTENTS
Page
FOREWORD 5
INTRODUCTION 7
Clause
1 Scope 9
2 Normative references 9
3 I.F. interface characteristics 11
3.1 Return loss 11
3.2 Level, frequency and spectrum of the modulator output signal 11
3.3 Carrier on-off ratio 11
3.4 Phase and amplitude balance 11
4 Terrestrial interface characteristics 13
4.1 Level and shape of the output signal 13
4.2 Other parameters 13
5 Bit error ratio 15
5.1 General consideration 15
5.2 Modem BER performance 15
5.3 Overall system BER performance 19
6 Frame acquisition and synchronization 19
6.1 General considerations 19
6.2 Clock frequency and acquisition time 21
6.3 Receive frame acquisition and synchronization 21
6.4 Transmit frame acquisition 23
6.5 Transmit frame synchronization 25
6.6 Synchronization characteristics with additive noise 27
7 System control functions 27
7.1 General considerations 27
7.2 Reference station changeover test 27
7.3 Burst Time Plan and/or Channel Mapping Plan change test 29
7.4 Other monitor and control function tests, including service channels 29
Figures
1 Typical TDMA terminal equipment used in a traffic earth station 31
2 Typical arrangement for modem BER measurement 31
3 Typical arrangement for overall system BER test 33
4 Typical arrangement for frame acquisition/synchronization test 35

835-3-10 © IEC:1994 - 5 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
METHODS OF MEASUREMENT
FOR EQUIPMENT USED IN DIGITAL MICROWAVE
RADIO TRANSMISSION SYSTEMS —
Part 3: Measurements on satellite earth stations —
Section 10: Terminal equipment —
TDMA traffic earth station
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
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. The IEC
collaborates closely with the International Organization for Standardization (ISO) in accordance with
conditions determined by agreement between the two organizations.
2) 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.
3) They have the form of recommendations for international use published in the form of standards, technical
reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
International Standard IEC 835-3-10 has been prepared by sub-committee 12E: Radio-
relay and fixed satellite communication systems, of IEC technical committee 12: Radio-
communications.
The text of this standard is based on the following documents:
DIS Report on voting
12(CO)148 12E(CO)160
Full information on the voting for the approval of this standard can be found in the repo rt
on voting indicated in the above table.

835-3-10 © IEC:1994 - 7 -
INTRODUCTION
In a TDMA (Time Division Multiple Access) satellite communication system, the reference
earth station transmits the reference burst which provides a timing reference to the traffic
(non-reference) earth stations. In many TDMA systems, the reference earth station
monitors the operation of the traffic earth stations, and controls them in case of a burst
plan change, etc. Usually, at least two reference earth stations are included in a TDMA
system for redundancy purposes.
A block diagram of typical TDMA terminal equipment for a traffic earth station is shown in
figure 1. This section deals mainly with the method of measurement for the TDMA terminal
used in traffic earth stations. It consists of PSK modulator/demodulator (PSK modem),
Common TDMA Terminal Equipment (CTTE) and one or more Terrestrial Interface Mod-
ules (TIM). The PSK modem interfaces with the earth station r.f. equipment at an inter-
mediate frequency of typically 70 MHz or 140 MHz, and the TIE interfaces with the
terrestrial digital circuits.
The CTTE processes the transmit data from the TIE, produces transmit bursts, processes
received bursts and sends recovered data to the TIE. It also controls the acquisition and
synchronization functions.
Special measuring equipment specific to the system, such as the reference burst
generators, the burst negator, the burst mode bit error ratio measuring set, etc., may
sometimes be required for measurement of the TDMA terminal equipment. They may be
provided by the manufacturer of the TDMA equipment if they are not commercially
available.
The TDMA terminal equipment is usually provided with various built-in monitoring func-
tions with indicators and/or displays. In some cases, the tests are performed using these
monitoring functions.
Because different system designs may exist for some TDMA systems, some of the
methods of measurement described here may be inappropriate, or at least the detailed
procedures may be different. Therefore, it is necessary to consult the responsible system
operator and/or the equipment manufacturer, before beginning the measurements.
Some performance characteristics may be affected by the satellite round-trip delay time.
These effects can usually be evaluated only by on-site tests which are outside the scope
of this section.
835-3-10 © IEC:1994 — 9 —
METHODS OF MEASUREMENT
FOR EQUIPMENT USED IN DIGITAL MICROWAVE
RADIO TRANSMISSION SYSTEMS —
Part 3: Measurements on satellite earth stations —
Section 10: Terminal equipment —
TDMA traffic earth station
1 Scope
This section deals with methods of measurement on Time Division Multiple Access
(TDMA) terminal equipment. There are various type of TDMA systems which may differ,
for instance, in the bit rate, the frame/burst format, and/or the acquisition and
synchronization scheme.
In this section, the methods of measurement are described as generally as possible so
that they may be applicable to various TDMA terminal equipment used in many interna-
tional and regional satellite systems.
2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this section of IEC 835-3. At the time of publication, the
editions indicated were valid. All normative documents are subject to revision, and parties
to agreements based on this section of IEC 835-3 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated
below. Members of IEC and ISO maintain registers of currently valid International
Standards.
IEC 835-1-2: 1992, Methods of measurement for equipment used in digital microwave
radio transmission systems — Pa
rt 1: Measurements common to terrestrial radio-relay
systems and satellite earth stations — Section 2: Basic characteristics.
IEC 835-1-4: 1992,
Methods of measurement for equipment used in digital microwave
radio transmission systems — Part 1: Measurements common to terrestrial radio-relay
systems and satellite earth stations — Section 4: Transmission performance.

835-3-10 © IEC:1994
3 I.F. Interface characteristics
3.1 Return loss
The return loss of the modulator output po rt and the demodulator input po rt should be measured
according to IEC 835-1-2. The modulator is operating continuously.
3.2
Level, frequency and spectrum of the modulator output signal
Refer to IEC 835-1-2.
The level and the spectrum of the modulator output signal should be measured by
operating the modulator continuously with a pseudo-random binary sequence (p.r.b.s.)
present at the modulator input. If required, the spectrum should also be measured in the
burst mode.
The frequency of the modulator output signal should be measured in the continuous mode
with no modulation (CW mode).
3.3 Carrier on/off ratio
3.3.1
Method of measurement
Connect a spectrum analyzer to the output po
rt of the modulator and measure the level of
the carrier signal with the modulator output on and off. The on-off ratio is the difference of
the two levels in decibels.
3.3.2 Presentation of results
The results should be presented in decibels.
3.3.3 Detail to be specified
The following item should be included, as required, in the detailed equipment
specification:
a) minimum required on-off ratio.
3.4 Phase and amplitude balance
This measurement is usually carried out for QPSK modulators.
3.4.1
Method of measurement
Connect vector voltmeter probes to the modulated carrier output po rt and to the un-
modulated carrier monitor port, if available. Apply static binary symbols (00,01,11,10) to
the I/Q baseband input po rt
in sequences, and measure output carrier phase/amplitude
related to unmodulated carrier for each state.
Instead of the vector voltmeter, a constellation analyzer using the above principle can also
be applied.
835-3-10 © IEC:1994 - 13 -
3.4.2
Presentation of results
The results should be presented by stating the difference between the measured and ideal
values for the four individual states:
a) in degrees for the phase unbalance, and
b) in decibels for the amplitude unbalance.
3.4.3 Details to be specified
The following items should be included, as required, in the detailed equipment
specification:
maximum permitted phase unbalance between the phase states relative to an ideal
a)
value;
b) maximum permitted unbalance for the phase states.
4 Terrestrial interface characteristics
4.1 Level and shape of the output signal
4.1.1 Method of measurement
Drive an appropriate input port of the TIE by a suitable p.r.b.s. generator. The applied sig-
nal should be looped back at an appropriate point (digital or i.f. loopback) so that a bit
stream is obtained from the output po rt of the TIE to be measured. The level and shape of
the output signal should be measured from the oscilloscope display.
4.1.2
Presentation of results
The results should be presented as a copy of the oscilloscope display with time and ampli-
tude information included.
4.1.3 Details to be specified
The following items should be included, as required, in the detailed equipment
specification:
a) ports at which the measurements are to be performed;
b) bit rate and its tolerance;
c) code, e.g. B8ZS;
d) test load impedance;
e) mask of the pulses.
4.2 Other parameters
The following items should be measured, referring to IEC 835-1-2, "Basic characteristics":
return loss of terrestrial interface;
a)
b) clock frequency.
835-3-10 © IEC:1994 - 15 -
5 Bit error ratio
5.1
General consideration
The BER
should be measured with additive white Gaussian noise. Carrier-to-noise ratio
(C/N)
should be set to obtain the specified energy per bit to noise density ratio (Eb/No).
5.2
Modem BER performance
5.2.1 Definition and general considerations
A burst mode BER
test set,which may be specific to the TDMA system, is required to
measure the burst mode BER performance of the modem. Usually burst signals of various
lengths with specified preamble sequences can be generated at the modulator output
using a burst mode BER test set. At the receive side, it may be necessary to sample a
specified portion
(BER measuring window) of the received burst. This may be required to
assess the difference of the BER BER
performance with respect to the position of the
measuring window within the burst.
5.2.2 Method of measurement
5.2.2.1 Test set-up
BER
A typical test set-up arrangement is shown in figure 2. The burst mode test set is
connected to the modulator input and the demodulator output. The modulator output i.f.
signal is combined with i.f. noise generated by the i.f. noise source and connected to the
demodulator input. Attenuators are used to adjust the signal and the noise level.
A power meter, connected through a calibrated bandpass filter with known equivalent
noise bandwidth, is used to measure the signal and noise power to set a value of Eb/No.
The bandwidth of the filter should be less than the bandwidth of the i.f. transmission pass-
band.
5.2.2.2 Setting of a value of Eb/No
Refer to figure 2.
1) Setting a value of Eb/No is usually performed using a CW carrier which has the same
power as the modulated carrier used for the BER measurement, to avoid the effect of
the bandpass filter on the wide bandwidth modulated carrier power. To take into ac-
count the power difference between the CW carrier and the modulated carrier, first
connect the power meter (without the bandpass filter) to the output of attenuator 1.
Set attenuator 1 to obtain the specified output power and record the reading of the
power meter with modulated carrier. The modulator is then switched to CW mode
and attenuator 1 is adjusted to obtain the same power meter reading as in the
modulated case. Then reconnect the output of attenuator 1 to the combiner.
2)
Connect the power meter through a calibrated bandpass filter, to the output of attenuator
3 to measure the demodulator input level. Switch off the i.f. noise source and adjust
attenuator 3 to obtain the s
...