Spectrum Analyzer Mode
R&S
®
Cable Rider ZPH
217
User Manual 1321.0950.02 ─ 07
4. Enter the number of the grid line you want the reference level to position at.
The range is from 0 to 10. "0" corresponds to the lowest grid line, "10" corresponds
to highest grid line.
8.2.3.2
Setting a Display Range
The display range determines the scaling or resolution of the vertical axis. In the
default state, the display range is a logarithmic scaling over a 100 dB. This corre-
sponds to 10 dB per grid division. The R&S Cable Rider ZPH provides other display
ranges that either increase or decrease the resolution of the vertical axis.
However, increasing resolution does not increase the accuracy of, for example, the
marker level readout, but only makes it easier to read values off the trace.
You can also select a linear scale for the vertical axis. In that case, the power levels
are expressed as a percentage of the reference level. Linear scaling is useful to dis-
play AM modulated carriers in the time domain, for example.
1. Press the [SCALE/AMPT] key.
2. Select the "Range / Ref Pos" softkey.
The R&S Cable Rider ZPH opens a submenu to select the display range.
3. Select the display range you need.
The R&S Cable Rider ZPH adjusts the vertical axis accordingly.
8.2.3.3
Selecting the Display Unit
By default, the vertical axis (and therefore the reference level) is scaled in dBm. How-
ever, the units dBmV, dBV, Watt and Volt are also available. Selecting the right unit is
relevant for the marker level display because the unit of the marker level is the same
as the reference level.
1. Press the [SCALE/AMPT] key.
2. Select the "Unit" softkey.
The R&S Cable Rider ZPH opens a submenu to select the display unit.
3. Select one of the available units.
The R&S Cable Rider ZPH adjusts the vertical axis accordingly.
8.2.3.4
Setting a Reference Offset
You can define a reference offset for the reference level. With a reference offset, you
can increase the reference level by a certain amount. This is useful, for example, if an
attenuator or amplifier has been inserted before the RF input. The R&S Cable Rider
ZPH automatically takes the loss or gain into account when the level is displayed and
no manual calculations are necessary. A loss introduced at the RF input must be
entered as a positive number and a gain as a negative number.
Configuring Spectrum Measurements
