Bluetooth Measurements (Option K8) R&S FSL
1300.2519.12 2.44 E-11
Impact of the sweep count on the measurement results
Trace Mode Continuous Sweep Single Sweep & Sweep Count
Clear Write All measurement results (min., max.,
average) are updated with every sweep.
The corresponding values are
calculated based on the current curve.
Starts a measurement with n sweeps (n
= sweep count).
All measurement results (min., max.,
average) are calculated based on these
n sweeps.
AVG, MaxHold, MinHold All measurement results (min., max.,
average) are updated with every sweep.
The corresponding values are
calculated based on the current curve.
The trace is the continuous average
value (AVG) or the extreme value
(MaxHold, MinHold) since the start of
the measurement.
Starts a measurement with n sweeps (n
= sweep count).
n defines the number of sweeps that
are taken into account for the trace
math functions (AVG, MaxHold,
MinHold). The n sweeps result in one
trace and the measurement results
(Min, Max, Average) are calculated
based on this summarized trace.
The functions described above differ from the detector functions of the instrument:
Detectors combine the measurement data obtained by oversampling to one measurement point on
the screen. The kind of combination (Max Peak, Min Peak, Average, RMS) can be selected.
The trace functions affect complete measurement curves: A resulting curve is calculated from
several subsequent sweeps. The method of calculation (Average, Maxhold, Minhold) can be
selected here as well.
Thus the detector is the arithmetic rule for how sample data collected with a high data rate are
combined to a measurement point of one individual measurement curve, whereas the trace mode is the
rule of how samples taken from several measurement curves are to be combined to a new resulting
curve.
For the ACP measurement, the Average detector is set.
Trigger Concepts
As the DUT (Device Under Test) uses frequency hopping, a trigger method is necessary for two
reasons:
A measurement is only possible during the period of time, when there is a TX signal (burst) at the
frequency under request.
In order to determine the modulation characteristics correctly, a synchronization with the preamble
of the signal must be supplied.
If the Find Sync softkey is activated, the synchronization is supplied towards the 64 bit sync word. For
this purpose, in a first step a burst is searched automatically within the RF signal, or, if selected, the
external trigger or the IF power trigger are used to determine the burst position.
In a second step the sync word position is searched by correlation of the signal with the sync word
defined in the initialization phase. The correlation is performed directly with the FM signal, not with the
data bits, which are only available after the phase shifter has been processed. The find burst process is
continued as long as no sync word is found.
After the position of the sync word has been determined, the position of the p0 bit is calculated from the
average value of all zero trespassing points, as defined in the RF test specification. Finally the samples
are moved in a way that each sample matches one zero trespassing point (phase shifting).
The only measurement possible without synchronization is the Output Power measurement. The
specified measurement time is 20% to 80% of the burst length. Without synchronization the burst length
is defined via the –3dB points of the power curve. With synchronization the burst starts with the p0 bit.
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