User manual

38
Analysis
use the universal knob to enter the name of your choice
and you can save it by using the ACCEPT key. The name
will now be displayed Instead of the generic labels MA1 to
MA5. You can specify the names for all equations separa-
tely. Once all equations, constants and names have been
entered, you may also choose a name for this formula set
by pressing the NAME key in the formula set menu and
entering the name of your choice.
9.1.3 Example for using the extended math
This example shows the analysis of an electrical energy
waveform. The voltage across the load is being measured
with differential probe and applied to channel 2. The cur-
rent is being measured with a current probe and applied to
channel 1. First, the conversion factor of the current probe
(100 mV/A) will be entered. The formula set 1 will be ope-
nedandtheequationMA1willbedened.Afterpushing
the soft menu key EDIT, the appropriate functions can be
selected using the universal knob in the CURSOR/MENU
section. In this example, channel CH1 will be multiplied
with a constant (0.1) and the unit A (Ampere) will be assig-
ned. This ensures the correct display of the scale factors as
well as the units for cursors and automatic measurements.
The equation MA1 can be named „CURRENT using the
soft menu key LABEL.
Fig.9.5:Denitionofthecurrentequation
Fig.9.6:Denitionofthepowerequation
Afterwards, a new equation MA2 will be entered and ad-
justed. The result of the equation calculation „CURRENT“
and channel CH2 will be multiplied which will be yielded
to a power curve. The equation MA2 can be named „PO-
WER“ using the soft menu key LABEL. At last, a 3rd equa-
tion MA3 will be added to the set of formulas which will
bedenedastheintegraloftheequation„POWER“.The
equation MA3 can be named „ENERGY“ using the soft
menu key LABEL.
Now,alldenitionswillbecompletedandtheresultscan
be displayed and analysed. The math analysis can be per-
formed with cursor or automatic measurement functions.
All measurement results will be correctly shown and sca-
led with correct units: Ampere, Watt, Joule.
9.2 Frequency Analysis (FFT)
In general, the FFT in an oscilloscope works differently than
in a spectrum analyzer and is affected not only by the time
base setting, but also by the available number of used
a
cq
uired data points when calculating the FFT. The
R&S®HMO1002 allows you to include up to 65k point in the
FFT.
The FFT menu in the ANALYZE section allows a quick Fou-
rier transformation which displays the frequency spectrum
of the measured signal. The changed display allows you
to determine the most frequent frequencies in the signal
and the corresponding amplitude. Once the FFT key was
pressed, the screen will be divided into two graticules.
The upper left of the display shows information about the
settings in the time range, the area between the upper and
the lower window shows details about zoom and posi-
tion, and the section below the large FFT display window
indicates the settings (Span and Center) in the frequency
range. The lower FFT display window will be outlined in
white when the FFT is activated. This means that the large
knob in the time range section is used to select the span.
ThespanisspeciedintheunitHz(Hertz)andidenties
the width of the shown frequency range. The span posi-
The FFT is not suitable for the analysis of very slow signals (Hz-
range); this type of analysis requires a classic oscilloscope mode.
Fig. 9.7: FFT illustration