ETTC'2003 - SEE

Typical applications for the REM include:
Earth terminal and satellite payload testing
Satellite system integration test beds
Multichannel jammers
3.2 CHANNEL PROPAGATION EMULATOR
The ECP (Channel Propagation Emulator) synthesises the principal phenomena of propagation occurring
on RF signal links between earth-space. Designed by CNES, the ECP has been developed for CNES by
the R&D laboratory of SMP.
The ECP applies a transfer function on an intermediate frequency input at 1.125 GHz to two outputs, with
the following parameters:
Level attenuation (two channels)
Absolute delay and Jitter
Frequency Doppler shift
Typical applications for the ECP include:
Earth terminal and satellite payload testing
Satellite system integration test beds
3.3 ANTENNAS MATRICES
In order to analyse performances of the complete transmission system it is necessary to represent the
effect of interferers coming from the on-board antennas. As it is not possible to integrate directly real
antennas on the bench, the choice has been done to develop dedicated equipment, called the Antennas
Matrices. These equipment allow the control of the level of interfering signals onto the useful signal using
combiners, dividers and step attenuators. These equipment can take into account up to 15 different
interfering signals which is representative of a worst case of frequency reuse schemes. Furthermore, these
Antennas Matrices could be virtually splitted in two, in order, for example, to represent simultaneously
the interferers occurring on both forward and return link of a two-way satellite system. Designed by
CNES, the Antennas Matrices have been developed for CNES by the SEO company.
3.4 CONTROLLED PHASE NOISE
CARRIER GENERATOR
-40
The Controlled Phase Noise Carrier
Generator (CPNG) is a frequency
synthesiser allowing phase noise control up
to 3000 MHz operating frequency band.
Designed by CNES and developed by
-60
ELTA, the synthesiser is based on a phase
locked loop SP8855E chip with RF external
reference (< 100 MHz).
The phase noise template is defined by
adjusting the division ratio (N) used to
-80
-100
perform the phase/frequency comparison -120
between VCO and RF reference. A
theoretical 20log(N) degradation is obtained
between the synthesiser output and the
reference phase noise template. A third order
active low pass filter in the feedback loop
-140
gives possibilities to adjust the cut off frequency of the PLL.
L(f) en dBc/Hz
100 1000 10000 100000
Distance à la porteuse en Hz
This equipment is currently used to create a controlled phase noise on the useful channel, in particular to
identify very accurately the maximum phase noise mask admissible for the system.
3
Référence
gabarit n°1
gabarit n°2
gabarit n°3
Norme Intelsat