GUI Reference
R&S
®
ZNB/ZNBT
491
User Manual 1173.9163.02 ─ 38
●
In power sweeps, "StimVal" provides the voltage in V that results from the source
power in dBm. To obtain the correct source power in dBm (for "dB Mag" trace for-
mat), "Result is Wave Quantity" must be enabled. Note that, due to the conversion
into a dBm value, the source power depends on the reference impedance of the
port associated with the measured wave quantity, to be set in the "Balanced Ports"
dialog.
●
In time sweeps, "StimVal" is the stimulus time in s.
●
In CW mode sweeps, "StimVal" is the number of the point.
Remote command:
CALCulate<Chn>:MATH[:EXPRession]:SDEFine
CALCulate<Chn>:MATH:WUNit[:STATe]
Result is Wave Quantity
Controls the conversion and formatting of the mathematic expression.
●
If "Result is Wave Quantity" is enabled the analyzer assumes that the result of the
mathematical expression represents a voltage. Examples for voltage-type expres-
sions are all terms proportional to a wave quantity (e.g. 1.1*Data, if a wave quantity
is measured) or to a stimulus value of a power sweep. If "Show as": "Power" is
selected in the "More Wave Quantities" dialog, the result is converted into a linear
power before the selected trace format is applied. Otherwise no conversion is per-
formed, and "dB Mag" results are referenced to 1 μV.
●
If "Result is Wave Quantity" is disabled the analyzer assumes that the result of the
mathematical expression is dimensionless. Examples for dimensionless expres-
sions are all terms proportional to ratios of wave quantities, e.g. Data / Mem2[Trc1].
The selected trace format is applied without previous conversion.
"Result is Wave Quantity" acts on the result of the mathematical expression only.
Wave quantities and power sweep stimulus values always enter into the expression as
voltages.
Effect of "Result is Wave Quantity"
In the
, the "Show as" control element specifies whether
wave quantities are displayed as voltages or equivalent powers, using the port impe-
dances for a conversion between the two representations. "Result is Wave Quantity" is
relevant for mathematical traces displayed in units of dBm ("Show as": "Power" and
trace format "dB Mag" ):
If "Result is Wave Quantity" is on (checked), the mathematical trace values <W> are
interpreted as voltages and first converted into equivalent powers (<W> —> <P> =
<W>
2
/Re(Z
0
)). Results in "dB Mag" format are calculated according to <P>
log
= 10 * log
(<P>/1mW).
●
If "Result is Wave Quantity" is off, the mathematical trace values <W> are interpre-
ted as dimensionless quantities. Results in "dB Mag" format are calculated accord-
ing to <W>
log
= 20 * log (<W>).
Trace Config Softtool
