HW V4 / © 2005 – 2013 Aaronia AG, DE-54597 Strickscheid
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Manual Spectran V4
Functional description
5.3.13. Detect
(Detector type)
The Detect option can be used to choose a detector type.
Depending on the signal type and measurement standard,
different types of detectors are appropriate, the default being
RMS. Currently available types (more are in development)
are:
RMS (Root Mean Square)
The square root of the squares of all samples (I²+Q²). This
detector type has no corresponding symbol in the Mode
status field. It can be used to determine the real signal
power during sweep time on a certain frequency and is the
mandatory detector type for a variety of exposure limit
standards, for example, ICNIRP.
MinMax (PEAK)
This detector type compares the current (I²+Q²) sample
against the strongest formerly acquired sample. The
strongest respective sample is being kept and its Min/Max
displayed. The Mode status field shows the “Pulse” symbol.
This detector is particularly suitable for signals with high
crest factors (WiMAX, DVB-T etc.) or frequency hopping
(DECT) to determine the crest factor or signal peak. In
MinMax mode, signals are displayed with a hatched fill if the
signal’s corresponding graphic is wide enough to
accommodate for this (small Span). The “size” of the portion
of the graphic above the hatched part indicates the signal’s
MinMax value.
After pressing the DECT hotkey (key 0), a DECT phone is
being measured (MinMax mode is set automatically). Time
Domain mode is being selected as well. An actual DECT
signal would reveal itself in the spectrum as a number of
sporadically appearing, sharp peaks with varying heights. In
contrast, interference from a cellphone would be displayed
as a fence like, uniform collection of peaks of almost equal
height. As you can see, different signal sources can be
easily distinguished. This distinction is even more appealing
when using our PC analysis software “MCS”, with signals
being displayed as 3D graphics in Time Domain mode.
Note
: In MinMax mode, residual noise is always increased by roughly 10dB due to
mathematical reasons.
Tip
: You can always switch between the RMS and MinMax modes with the shift key – one
case where this is useful is determining the crest factor (the difference between RMS and
MinMax).
