Test Specification for Eurobalise FFFIS

Page 42 of 332
SUBSET-085, Issue 2.2.2
November 9, 2007
4.2.3.3 Balise Tele-powering Conformity Measurements in Contact Zone
4.2.3.3.1 Test Configuration
A proposed test set-up is shown in Figure 11 below. Clause F1 of Annex F on page 287 gives an example of
suitable test equipment. See also sub-clause 4.2.1 on page 23.
10.
Power
Meter 2
50 Ohm
3.
RF
Amplifier
4.
Attenuator
27 MHz
P M2
C.S.
Test Antenna
4.2 MHz
5.
2.
1.
Attenuator
Signal
Generator
12.
15.
Filter
Power
Meter 3
P M3
17.
Balise
Interface ‘A’
4.2 MHz
Antenna
Figure 11: Test set-up for Balise conformity Tele-powering
4.2.3.3.2 Test Abstract
This measurement procedure will give a value P 27BA for each measurement point, defined in clause C1 of Annex
C on page 200, which shall be compared with the corresponding reference value P 27RL for the Reference Loop
measured in sub-clause 4.2.3.2.3 on page 41. The value P 27BA is proportional to the square of the 27 MHz current
needed for obtaining a flux level of φ d1 through the Balise. The current is measured with Power Meter 2
(P M2 ), compensated, and called P 27BA. .
To find out when the Balise receives a flux of φ d1 the Balise response is measured with a fixed 4.2 MHz Antenna.
In the first measurement position the 4.2 MHz response is measured with the same 27 MHz current that
in the Test Antenna gave a flux of φ d1 through the Reference Loop. For each new position of the Test Antenna
the 27 MHz power in the Test Antenna is adjusted to give a 4.2 MHz response that is equal to the first measurement
position.
It is allowed to modify the φ d1 test level so that it is ensured that the Balise is operating in a linear region (at least
±1.5 dB wide) suitable for the test. In case there is no such region, a smaller region can be selected individually
for each position.