SIST EN 60835-1-3:2002/A1:2002

• Abstract:

  EN following parallel vote

• Status: Published
• Publication Date: 30-Sep-2002
• ICS: 33.060.30 - Radio relay and fixed satellite communications systems
• Technical Committee: OMS - Equipment used in mobile services and satelite comunication systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Oct-2002
• Due Date: 01-Oct-2002
• Completion Date: 01-Oct-2002
• Ref Project: EN 60835-1-3:1995/A1:1995 - 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 3: Transmission characteristics

• Amends: SIST EN 60835-1-3:2002 - 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 3: Transmission characteristics
• Effective Date: 21-Sep-2010

SIST EN 60835-1-3:2002/A1:2002 is the Slovenian adoption of an amendment to the IEC method of measurement for digital microwave radio transmission systems. It updates Part 1, Section 3 on transmission characteristics for terrestrial radio-relay systems and satellite earth stations. The amendment adds a new clause on delay difference between two transmission paths, so manufacturers and test labs can check switching and diversity performance in practice.

What does SIST EN 60835-1-3:2002/A1:2002 specify?

SIST EN 60835-1-3:2002/A1:2002 specifies an addition to the transmission-characteristics measurements in IEC 60835-1-3. The added material covers delay difference between two transmission paths, how to measure it at the i.f. interface, how to present the results, and what details need to be stated in an equipment specification.

The amendment is organized as:

• Clause 6, with subclauses 6.1 to 6.4
• Figures 8 to 13, which show the system example, test arrangements, CRT displays, and the absolute-delay setup

The note in the clause points readers to IEC 835-2-5:1993 for baseband delay-difference measurements. In this amendment, the focus is on i.f. measurements used in radio-link testing and adjustment.

What are the key requirements of SIST EN 60835-1-3:2002/A1:2002?

Why delay difference matters

Clause 6.1 says delay difference between two transmission paths is important because it affects slipless switching between a main and a stand-by channel, and it also influences diversity switching and combining. In practice, this means the paths in a protected or diversity system must be aligned closely enough that switching does not upset service.

Clause 6.1 also says the measurements in this section are for i.f. delay difference only. It says delay equalization in terrestrial systems may be manual or automatic, and that the limiting delay values that can be equalized should be measured during factory tests using simulated transmission paths.

How the measurement is made

Clause 6.2 describes a setup using a test transmitter, a radio link measuring set or microwave link analyser (MLA), and a test receiver in group-delay measurement mode. The swept signal is divided to feed the main and diversity receivers through cables of identical length, and an electronic change-over switch is placed between the two i.f. outputs and the test receiver.

The measurement uses a sweep width of less than 1 MHz at the centre frequency. The result appears as a step function on the CRT display, and the delay difference AT is read from the step height. An alternative method uses a square-wave drive signal from a function generator. In practice, cable equality and the correct switch drive are what make the reading meaningful.

Clause 6.2 also describes a simple arrangement for measuring the absolute delay of an i.f. component or sub-assembly. This is useful when receiver components must be matched, for example in satellite earth station systems that use frequency-hopping.

How results are recorded and what the specification must say

Clause 6.3 says results shall be presented either as a plot or photograph of the CRT display, or as measured values of Ai. That gives labs two acceptable ways to record the test outcome, either visually or as numeric data.

Clause 6.4 says the detailed equipment specification shall state:

• the maximum allowed delay difference or absolute delay
• the values of Δz to be adjusted for certain tests
• the interface points of measurement
• the measuring equipment parameters, test frequency, switching frequency, sweep width, and centre frequency

This matters because the test conditions have to be fixed in advance if the result is to be repeatable and comparable between suppliers or test sites.

What terms does SIST EN 60835-1-3:2002/A1:2002 define?

• Delay difference between two transmission paths - the timing mismatch between two signal paths, such as a main and diversity branch.
• Absolute delay - the delay of an i.f. component or sub-assembly measured against a reference path.
• Intermediate frequency (i.f.) - the frequency stage used for the measurements in this clause.
• Microwave link analyser (MLA) - test equipment used as the signal source in the measurement arrangement.
• Cathode ray tube (CRT) display - the test-receiver display from which the delay step or Ai value is read.
• Bit error rate (BER) - the quality measure used in the related switching arrangement shown in Figure 12.
• Pseudo-random binary sequence (PRBS) generator - the signal source used in the switching-characteristics arrangement in Figure 12.

Who uses SIST EN 60835-1-3:2002/A1:2002?

This amendment is used by manufacturers of digital microwave radio transmission equipment, test laboratories, and engineers who set up or verify terrestrial radio-relay systems and satellite earth stations. It is also relevant to production and acceptance testing teams, because the clause includes factory-test and component-delay measurements.

System integrators and maintenance engineers use it when working on diversity switching, combining, receiver alignment, and frequency-hopping links. Quality managers and buyers can use it to define what delay-related test data should be supplied with equipment.

What changed in SIST EN 60835-1-3:2002/A1:2002 from the previous edition?

SIST EN 60835-1-3:2002/A1:2002 is Amendment 1 to IEC 60835-1-3:1992. The amendment adds a new Clause 6 on delay difference between two transmission paths, together with subclauses 6.1 to 6.4 and Figures 8 to 13.

Which standards are used with SIST EN 60835-1-3:2002/A1:2002?

Standard	What it contributes
IEC 60835-1-3:1992	The base Section 3 on transmission characteristics that this amendment updates
IEC 835-2-5:1993	Baseband delay-difference measurements, mentioned in the note for related use
IEC 835-2-7:1993	Diversity switching and combining equipment measurements, mentioned for related switching tests

What does the SIST EN 60835-1-3:2002/A1:2002 document contain?

The document contains the new clause text for delay-difference measurements and the added figures that show the test setups and display examples. Figures 8 to 13 cover a space diversity receiving system, the arrangement for measuring delay difference between two branches, CRT displays for synchronized and non-synchronized switching, a switch-over setup as a function of delay difference, and the measurement of absolute delay of an i.f. component or sub-assembly.

It also gives the practical test parameters that matter in the lab, including sweep width, centre frequency, switching frequency, and the measurement points to be used. For users, that makes the amendment a working measurement guide rather than a general description of performance.

SLOVENSKI STANDARD
01-oktober-2002
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 3: Transmission characteristics -
Amendment A1 (IEC 60835-1-3:1992/A1:1995)
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 3: Transmission characteristics
Meßverfahren für Geräte in digitalen Mikrowellen-Funkübertragungssystemen -- Teil 1:
Messungen an terrestrischen Richtfunksystemen und Satelliten-Erdfunkstellen --
Hauptabschnitt 3: Übertragungseigenschaften
Méthodes de mesure applicables au matériel utilisé pour les systèmes de transmission
numérique en hyperfréquence -- Partie 1: Mesures communes aux faisceaux hertziens
terrestres et aux stations terriennes de télécommunications par satellite -- Section 3:
Caractéristiques de transmission
Ta slovenski standard je istoveten z: EN 60835-1-3:1995/A1:1995
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
60835-1-3
STANDARD 1992
AMENDEMENT 1
AMENDMENT 1
1995-03
Amendement 1
Méthodes de mesure applicables au matériel
utilisé pour les systèmes de transmission
numérique en hyperfréquence -
Partie 1:
Mesures communes aux faisceaux hertziens
terrestres et aux stations terriennes de
télécommunications par satellite -
Section 3: Caractéristiques de transmission
Amendment 1
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 3: Transmission characteristics
© CEI 1995 Droits de reproduction
réservés — Copyright — all rights reserved
Bureau Central de la Commission Electrotechnique Intern Genève, Suisse
ationale 3, rue de Varembé
Commission Electrotechnique Internationale CODE PRIX
International Electrotechnical Commission PRICE CODE
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0 Pour prix, voir catalogue en vigueur
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835-1-3 Amend.l © IEC:1995 - 3 -
FOREWORD
This amendment has been prepared by sub-committee 12E: Radio relay and satellite
communication systems, of IEC technical committee 12: Radiocommunications.
The text of this amendment is based on the following documents:
DIS
Report on voting
12E(CO)167 12E/252/RVD
Full information on the voting for the approval of this amendment can be found in the
repo rt on voting indicated in the above table.
Page 3
CONTENTS
Add the following items:
6 Delay difference between two transmission paths 5
6.1 Definitions and general considerations 5
6.2 Method of measurement 5
6.3 Presentation of results 7
6.4 Details to be specified 9
Figures
8 Example of space diversity receiving system where delay difference
could be a problem 9
9 Arrangement for measuring delay difference between two branches of
a diversity system 11
10 Delay difference measurement: CRT display for a synchronized switch 11
11 Delay difference measurement: CRT display for a non-synchronized switch 11
12 Arrangement for measuring the switch-over characteristics as a function
of delay difference 13
13 Measurement of absolute delay of an i.f. component or sub-assembly 15

835-1-3 Amend.1 © IEC:1995 - 5 -
Page 23
Add the following new clause:
6 Delay difference between two transmission paths
6.1 Definitions and general considerations
ant parameter with
The delay difference between two transmission paths is an impo rt
respect to the availability of radio links for the following reasons:
- the delay difference should be kept within certain limits in order to achieve slipless
switching between any main and a stand-by channel;
- the delay difference greatly influences the performance of functions such as
diversity switching and combining between any two channels.
NOTE - This clause refers only to i.f. delay-difference measurements. Baseband delay-difference
measurements are dealt with in IEC 835-2-5: 1993, Methods of measurement for equipment used in
digital microwave radio transmission systems - Part 2: Measurements on terrestrial radio-relay systems -
Section 5: Digital signal processing sub-system.
In terrestrial systems, means are provided to equalize delay differences either manually or
automatically. In order to assess the performance of these methods, the limiting delay
values which can be equalized by such techniques shall be measured using simulated
transmission paths during factory tests.
Figure 8 shows an example of a space diversity receiving system.
Another parameter to be measured is the absolute delay of receiver components during
rtance in
production or acceptance testing. For example, this measurement is of great impo
satellite earth station systems where "frequency-hopping" is used. In this case, the delay
difference between switched transmission paths should be adjusted to minimum.
Such absolute delay equalization can be carried out at the i.f. inte rfaces of the concerned
radio link receivers using commercially available test equipment.
6.2 Method of measureme
...