Page 140 - TBIS_15194-2019_(EN)_3nd

TBIS 15194:2019

C.4.6.2.2 For the purpose of monitoring the external part of the EPAC and of
determining whether the conditions laid down in C.4.6.2.1 have been met, a video
camera may be used.

C.4.6.2.3 If a EPAC does not meet the requirements of the tests defined in C.4.6.2,
steps shall be taken to verify that the faults occurred under normal conditions and
are not attributable to spurious fields.

C.4.7 Generation of the requisite field strength

C.4.7.1 Test method
a) The “substitution method” is to be used for the purpose of creating the field test

conditions.
b) Substitution method: for each test frequency required, the RF power level of the
field generator shall be set so as to produce the required test field strength at the

reference point of the test area without the EPAC being present. This RF input
power level, as well as all other relevant settings on the field generator shall be
recorded in the test report (calibration curve). The recorded information is to be
used for type-approval purposes. Should any alterations be made to the

equipment at the test location, the substitution method shall be repeated.
c) The EPAC is then brought to the test installation and positioned in accordance
with the conditions laid down in C.4.5. The power required by C.4.7.1 b) is then

applied to the field generator for each of the frequencies indicated in C.4.6.1 a).
d) Whatever field-definition parameter is chosen in accordance with the conditions

laid down in C.4.7.1 b), the same parameter shall be used in order to determine
the strength of that field throughout the test.
e) For the purposes of this test, the same field generating equipment and the same

equipment configuration shall be used as in the operations conducted in
pursuance of C.4.7.1 b).

f) Field strength measuring device:
Under the substitution method, the device used to determine the field strength
during the calibration stage should take the form either of a compact isotropic

probe for measuring field strength or of a calibrated receiving antenna.
During the calibration phase of the substitution method, the phase mid-point of

the field-strength measuring device shall coincide with the reference point.
If a calibrated receiving antenna is used as the field strength measuring device,
readings will be obtained in three directions at right angles to each other. The

equivalent isotropic value corresponding to these measurements is to be regarded
as the field strength.

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