R&S FSH
Measurements on CW Signals
1145.5973.12 2.3
E-14
Using markers is also an effective way to shift the trace maximum so that it coincides with the top of the
measurement diagram. If the marker is positioned on the trace maximum (as in the example), the
reference level can be set to the marker level by entering the following keystrokes:
Press the MARKER key.
Press the SET MARKER softkey.
Select REF LVL = MRK LVL in the submenu by using the rotary knob or the cursor keys.
Press the ENTER key.
The reference level is then set to the measured level indicated by the marker. Only a few keystrokes
are needed to set the optimal reference level.
Frequency Measurements
The R&S FSH’s trace displays 301 measurement points (associated with 301 frequency or time points
along the x axis). The marker is always positioned on one of these measurement points. The R&S FSH
calculates the marker frequency from the measurement-point frequency, and the center frequency and
frequency span that have been set. The measurement point resolution and, consequently, the accuracy
of the marker-frequency readout therefore depend on the frequency span that has been selected.
The R&S FSH has a frequency counter to increase the accuracy of the marker frequency readout, It
stops the sweep at the marker position, counts the frequency and then continues the sweep.
The following measurement example is based on the previous example.
Press the MARKER MODE softkey in the marker
menu.
The marker mode selection box opens.
Select FREQ COUNT from the selection box using
the rotary knob or the cursor keys.
Press the ENTER key.
The label 'M:' at the upper left-hand corner of the
measurement diagram changes to 'Ct:' to tell you that
the frequency counter has been switched on. The
resolution of the frequency readout is now 1 Hz no
matter what span has been set. The accuracy is
determined by the R&S
FSH’s internal reference
frequency. It is far higher than that of pixel-oriented,
marker-frequency readout.
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