Gigahertz Solutions HFW59D Bedienungsanleitung Seite 26

M a d e in G e r m a n y
Nevertheless, the "true" mean value is of great interest, too:
 The "official" limit values are always based on these mean value
examinations. When analysing these results as well as those of cell
phone operators, it may, therefore, be useful to have a possibility
of comparison.
Users of professional spectrum analysers please note:
- "Peak" corresponds to the "Max. Peak" in µW/m² of a spectrum analyser.
- "RMS" corresponds the "true RMS" setting in µW/m² of a spectrum analyser.
- In broadband-measurement technology "Video bandwidth" (VBW) is understood
differently than in terms of spectrum analysis.
Peak Hold
In the interior, local peak values are mostly subject to strong fluctua-
tions (caused by multiple reflections). In order not to overlook any local
maxima (so called hot spots), indoor measurements should, therefore,
preferably be done with the "Peak hold" setting.
Switching impulses can cause "pseudo peaks" which will appear on
your display. These can be deleted by pressing and holding the "clear"
button for several seconds (while keeping the "clear" button pressed,
the measurement will turn into a regular peak measurement). Releas-
ing the "clear" button will trigger the period during which the maximum
value is to be determined.
In the "Peak hold" mode, the sound signal remains proportional to the
currently measured power flux density. This helps finding the absolute
maximum within the measured area.
The droop rate, at which the held peak value decreases over time can be controlled
with the "+" and "-" switch. Even after several minutes, the value displayed is still
within the specified tolerance. Nevertheless, the display should be checked frequently
in order to obtain the most accurate readings. In the case of very high and short signal
peaks, the holding capacity of the "Peak hold" function needs several recurrences to
fully load.
Evaluating the different radio services
As default, please use the settings "VBW Standard" and "Peak hold"
to simplify the measurement according to SBM. This ensures reliable
signal handling in order to apply the following correction factors for the
crest factors 8 of different radio services covered by this meter.
UMTS/3G, LTE/4G, 5G, WiMAX, DVB, as well as
Wireless LAN
during full data transmission
To compensate for the crest factors, multiply the displayed measured
value by a correction factor. A flat factor of ten provides a fairly good
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Ideally one would keep the setting "RMS", as the utilized circuitry by its nature en-
sures the correct display of RMS values independently of the signal's crest factor.
For practical reasons one can nonetheless use the convenient "Peak hold" setting,
as with "VBW standard" the readings for RMS and Peak won't differ significantly for
the signals in question.
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The modulation of these high-speed services includes high, needle-like peaks
compared to the average power transmitted. Such signals are referred to as "high
crest factor" signals, and can be identified with the help of the audio analysis.
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