63
Instrument Functions
As expected, less power will be transmitted from the
tracking generator to the input of the spectrum analyzer.
The delta to the previous zero line will be displayed.
Removing the connection at this point will create a delta
so big that the curve is outside of the display area (please
refer to figure 6.11):
In this case, using the reference offset function in the
AMPL menu the zero point can be moved and you get the
following image:
Fig. 6.11: Loosening of the RF cable completely
Fig. 6.12: Trace shifting with reference offset
Fig. 6.12 just only shows the noise at the input. But you
can see that the properties of the connection cable, which
had previously been connected, will be included.
6.8 The use of markers
The R&S®HMS-X offers several markers and delta markers
for the evaluation of curves. The markers are always tied to
the curve and indicate the frequency and the level at that.
The frequency position of the marker is marked by an ar-
row icon. The nurmerical values of the frequency and the
level are shown as a “M” at the top of the screen. The unit
of the level is the same as the unit selected for the refe-
rence level.
The knob allows to choose up to 8 different markers via
the MARKER menu. The individual markers can be swit-
ched on and off with the softkey Display. The softkey Po-
sition is used to set the frequency position of the marker
along the trace. The marker will be calculated from the dis-
play values (pixel). For example, if marker 1 is activated, a
frequency counter function can be enabled for this marker
by pushing the the softkey Counter. The corresponding fre-
quency value of the marker is now shown at the top of the
display marked with an „F“.
The values for the frequency marker will be calculated by
hardware (TCXO). When frequency measurements are
being made, the R&S®HMS-X briefly stops the sweep at
the marker position and measures the frequency using the
frequency counter (resolution 1 Hz). The frequency coun-
ter only gives completely accurate readings for sine signals
that are at least 20 dB above the noise floor. If the signal
noise ratio is less, noise affects the results.
If two different markers are activated (for example Marker1
and Marker2), you can calculate the delta between the
two markers with the softkey DELTA. The delta marker le-
vel is always relative to the level of the main marker (Mar-
ker1). The delta marker unit is always dB. If a marker is set
to delta mode it is marked by a “D” in the read out to dis-
tinguish it from a standard marker designated by a leading
“M”.
Fig. 6.13: Frequency counter
Fig. 6.10: Loosening of the RF cable
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