RF: Spectrum Measurement CMU
1100.4903.12 4.56 E-10
FETCh:SUBarrays:SPECtrum[:CURRent]?
FETCh:SUBarrays:SPECtrum:MINimum?
FETCh:SUBarrays:SPECtrum:MAXimum?
FETCh:SUBarrays:SPECtrum:AVERage? etc.
Statistic Count
Statistic Count defines how many sweeps are combined to form one statistics cy-
cle.
1 to 1000 sweeps Number of sweeps per statistics cycle
The settings 1 and OFF (press ON/OFF key) are equivalent. A statistics cycle de-
termines the duration of single-shot measurements (see Chapter 3, section General
Settings).
Remote control
CONFigure:POWer:CONTrol <MODE>,1 ... 1000 | NONE
Grid /
Scaling Mode
Grid switches on or off the grid in the graphical test diagram. In addition the Scaling
Mode, i.e. the number of grid cells in horizontal direction (frequency axis) can be
selected:
Variable The number of horizontal grid cells is adapted to the sweep span
of the Spectrum measurement, see page 4.50,
Constant The diagram consists of a constant number of 10 horizontal grid
cells.
Remote control
DISPlay:SPECtrum:CONTrol:GRID ON | OFF
Detect Mode
Detect Mode defines how the measurement curve is calculated from the entire set
of measurement points. The curve is interpolated from 560 points, each corre-
sponding to one pixel of the CMU's LC display. The number of measurement val-
ues is actually larger than 560; the coordinates of the pixels defining the curve can
be calculated in two alternative ways:
Peak The y-coordinate (power) of each pixel is equal to the maximum
of all measurement values falling inside the pixel range.
RMS The y-coordinate of each pixel is equal to the RMS average of all
measurement values falling inside the pixel range.
The two settings yield different curves, especially in domains where the signal
shows strong power variations (e.g. in the noise floor around a distinct spectral
lobe). RMS averaging tends to smooth out the spectral curve and to suppress the
noise. On the other hand, very narrow peaks may be underestimated if RMS Detect
Mode is set.
Remote control
[SENSe:]SPECtrum:DETector PEAK | RMS
Frequency
Frequency defines the center frequency of the measurement range in MHz or in
another frequency unit selected via the unit keys. The center frequency is identical
with the Center frequency set with the Analyzer Settings softkey.
Remote control
[SENSe:]SPECtrum:FREQuency:CENTer <Frequency>
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