Chapter 12 EMF (EMI) Operation
Measurement methods
9102 Handheld Spectrum Analyzer Software version 5.31
187
Stirring method Using the stirring method the user sets the measurement instrument to
maximum hold and moves the antenna within the designated measure-
ment area. Depending on the antenna used the user has to be very
thorough in covering the designated measurement area in order to
capture the different locations, directions of incidence, and polarisa-
tions equally. Using an isotropic antenna directions of incidence and
polarisations can be neglected, thus an isotropic antenna provides a
more comfortable solution for using the stirring method. For further
details on the characteristics of different antennas refer to “Measure-
ment antennas” on page 188. After completing the coverage of the
designated measurement area the measurement instrument provides
the maximum field strength value.
Multipoint method The multipoint approach involves a predefined multipoint matrix
providing the user with designated measurement points. For this
purpose the dimensions of the measurement area first have to be
determined and the measurement points have to be specified. At each
measurement point a measurement has to be taken. As three measure-
ments are required at each point (one for each direction, x y, z), it is
recommended to use an isotropic antenna for performing measure-
ments using the multipoint method. For further details on the charac-
teristics of different antennas refer to “Measurement antennas” on
page 188. The user performs the measurement at each of the
measurement points and documents the individual measurement
results.
Another possibility is to use a simplified approach to the multipoint
method. As for the stirring method the user sets the measurement
instrument to maximum hold and moves within the designated
measurement area covering all predefined measurement points using
an isotropic antenna.
Compared to the stirring method the multipoint method, whether in its
pure or in its simplified form, has the advantage of offering a guideline
to the user performing the measurements and thus constitutes a more
structured approach.
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