Fig. 3.4: Measurement Of The Harmonic Of A Sine Wave Signal; Fig. 3.5: Selection Of The Proper Filter Settings; Fig. 3.6: Measuremen Of The Harmonic Using The Delta Marker - Hameg HMS 3000 Handbuch

Activate the marker by pressing the soft key DISPLAY. The se-
cond marker will now appear in the center of the display. Select
the marker by pressing the soft key POSITION (the marker
indication will turn to orange) and move it with the knob (to the
right) or via the keyboard by directly entering the value 200 MHz.

Fig. 3.4: Measurement of the harmonic of a sine wave signal

3.3.1 Selection of the proper filter settings
In order to better resolve the harmonic from the noise, the RBW
and the VBW filters should be adapted to the measurement task
by using the bandwidth menu (key BANDW
standard procedure is to automatically set the RBW and VBW
filters such that a first approximation of a measurement of the
input signal will be possible. Manual selection of the filters will
be always superior to an automatic presetting.
Activate the key BANDW
9
spectrum analyzer. Due to the presettings, the RBW and the
VBW will be set to AUTO. Activate manual setting by pressing
the top soft key, then use the knob to select the 100 kHz filter
from the list in the menu which will appear.
The noise band displayed formerly should now be markedly
reduced such that the first harmonic will be better visible.
A further reduction of the RBW would display the harmonic
still better at the expense of a massively extended sweep
time. Here, a compromise must be found between display
quality and measurement time, optimum for the actual mea-
surement task.
Fig. 3.5: Selection of the proper filter settings
). The HMS series
9
to enter the filter menu of the
Q u i c k i n t r o d u c t i o n
Another means of spectrum analysis is the socalled video
bandwidth (VBW). This is nothing else but a low pass filter which
filters high frequency components from the signal. Using this
filter can also cause a massive increase of the sweep time, and
again a sound compromise has to be found between display
quality and measurement time.
Activate the manual VBW selection by pressing the associated
soft key and use the knob to select a 10 kHz filter from the list
in the menu which will appear.
Both levels (fundamental and harmonic) should now be well
visible on the HMS display.
3.3.2 How to measure the harmonic
In chapter 3.3.1 already two markers were positioned on the
fundamental and the harmonic, the second one on the harmonic.
Open the marker menu by pressing the key MARKER
The marker [2] is still selected (shown as an entry on the top
soft key) Change the active marker [2] from an „absolute"
marker to a „relative" DELTA marker by pressing the soft
key DELTA. The marker display will change from an absolute
frequency and level display to a relative frequency and level
display; the values shown refer always to the main marker
(marker [1]).

Fig. 3.6: Measuremen of the harmonic using the delta marker

3.3.3 Extended marker functions (PEAK SEARCH)
Press the key PEAK SEARCH in order to reach the extended
marker functions. Select the marker to be used with the key
(MARKER > 14 ). In the top screen area (where the level and
frequency values of the markers can be read) the lettering of
the marker selected will be shown pronounced bright.
Select the marker [2] and press the soft menu key PEAK. The
second marker should now jump to the same spot where mar-
ker [1] already resides (that is the position of the fundamental),
because the level of this is the highest. The values displayed
for (DELTA-) frequency and level should be „0".
Press the soft menu key NEXT PEAK in order to cause the ac-
tive marker to position again on the first harmonic. The values
displayed for (DELTA-) frequency and level should be identical
to the original ones.
15 .
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Subject to change without notice