© Gigahertz Solutions GmbH
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Made in Germany
Nevertheless, the “true” mean value is of great interest, too
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:
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The “official” limit values are always based on mean value ex-
aminations. When analysing “official” measurement results,
therefore, such as those for instance done for cell phone oper-
ators, it may be useful to have a possibility of comparison.
-
Different radio services will never have an equal ratio between
mean values and peak values. DECT cordless phones, for in-
stance, can have a ratio of as high as 1:100, while for GSM the
ratio may vary from 1:1 up to 1:8.
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Especially in the case of the new broadband modulated radio
services, such as LTE, the RMS value and - thanks to the crest
factor of max. 10 dB – also the arithmetical peak value can both
be reliably determined.
Users of professional spectrum analysers please note:
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The value for pulsed radiation shown on the display of the Gigahertz Solu-
tions HF Analysers with the signal switch set to “Peak” corresponds to the
equivalent value in µW/m² resulting from the “Max. Peak” function of a mod-
ern spectrum analyser (elder spectrum analysers had a similar function
mostly called “positive peak”).
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The switch setting “RMS” corresponds the “true RMS” setting of a modern
spectrum analyser (elder spectrum analysers have a similar function mostly
called “normal detect”, as well as a setting for the video bandwidth adapted
to match the pulse).
Setting: “Signal”
Peak hold
In the interior, local peak values are mostly subject to strong fluc-
tuations (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 measure-
ment). Releasing 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 con-
trolled 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 (less than a second) to fully load.
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Users of meters produced by other manufacturers please note: The a.m. con-
clusions are only feasible for recordings of the true mean value. They do not ap-
ply if your meter shows the momentary value of the modulated HF signal only in-
stead of the mean value, which is the case for most meters on the market, even
if their specifications state that it will display the mean value.
Содержание HF58B
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