ETTC'2003 - SEE

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Transmission Test Bench
Thierry Robert, Christophe Laporte, Francis Gizard, Alain Mallet, Jean-Philippe Taisant
CNES - DTS/AE/TTL/TS
18 ave Edouard Belin
31401 Toulouse cedex
email : thierry.robert@cnes.fr - tel : 33 (0) 5 61274114 - fax : 33 (0) 5 61282613
1 INTRODUCTION
For two years CNES has been developing a bench for transmission satellite systems engineering. This
development is performed under ATF (“Atelier Telecom du Futur”) project. The Transmission System
Bench (BST) is devoted to determine accurately the performances of the transmission satellite sub-system
including all the payload components such as multi-beam antennas, TWTA, Local Oscillators (phase
noise template), and including system impairments such as propagation constraints or interference
environment. Furthermore, this bench also offers the ability to analyse the impact of a given equipment in
"real" operational conditions over end-to-end transmission performances.
This paper presents the bench and its components as well as the kind of results that can be obtained
through its exploitation.
2 BENCH OVERVIEW
Emission
Rack
Monitoring
Module
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Modulator
Controller 15
14
15
14
Controller
15
16
15
14
13
12
11
10
9
8
7
6
5
4
Receive
Antenna
Matrix
16
15
14
13
12
11
10
9
8
7
6
5
4
15
13
12
11
10
9
8
7
6
5
4
3
2
1
Microwave
Chains
Interferers
13
12
11
10
9
8
7
6
5
4
3
2
1
15
16
15
14
13
12
11
10
9
8
7
6
5
4
Transmit
Antenna
Matrix
1
2
3
3
3
2
2
2
1
1
1
Calibrated
Noise Generator
2
3
1
Monitoring
Module
Propagation
Channel
Emulator
Microwave Chain
Useful channel
Propagation
Channel
Emulator
Monitoring
Module
1
3
2
Calibrated
Noise Generator
Demodulator
The BST aims to represent in a very realistic way the satellite transmission of a multimedia satellite
system from X to Ka band. This testbed is easily reconfigurable and its operation is facilitated by the
availability of friendly man-machine interfaces. The BST operates up to sixteen channels in order to
emulate several kind of interferers. It is organised around six sub-systems:
1. Modulated signals generator (QPSK, OQPSK, 16QAM) with varying bit rate from 1.6 kbits/s up to
400 Mbits/s.
2. ACPR (Adjacent Channel Power Ratio) controller,
3. Propagation effects and satellite motion emulator,
4. Satellite receive and transmit antennas emulator,
5. Microwave racks including TWTA, on board processor and phase noise generator.
6. Thermal noise generator.