Rohde & Schwarz 1145.1010.04/05/06, Operating Manual

Page: 220 / 813

Trace Menu R&S
®
ZVA/ZVB/ZVT
1145.1084.12 4.58 E-6
If traces are used as operands, the complex trace data (measurement results) enter into the
mathematical expression, irrespective of the current trace format.
Result is Wave Quantity in the lower part of the dialog 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 expressions 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 performed, and
dB Mag results are referenced to 1
µ
V.
•
If Result is Wave Quantity is disabled the analyzer assumes that the result of the mathematical
expression is dimensionless. Examples for dimensionless expressions 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 and numeric example
In the More Wave Quantities dialog, the Show as: control element specifies whether wave quantities are
displayed as voltages or equivalent powers, using the port impedances 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 interpreted as
dimensionless quantities. Results in dB Mag format are calculated according to <W>
log
= 20 *
log (<W>).
Example: A mathematical trace value amounts to 1 (real value); the port impedance is 50 . If Result is
Wave Quantity is on, the analyzer assumes the trace value to be 1 V, which is converted into a linear
power of 20 mW, corresponding to approx. 13 dBm. With Result is Wave Quantity off, the trace value 1
is directly converted into a logarithmic power of 0 dBm.
See also example for
CALCulate<Ch/Tr>:MATH:WUNit:STATe ON | OFF.
Remote control: CALCulate<Ch/Tr>:MATH:WUNit:STATe ON | OFF
Transform
Opens a submenu to view the measurement results as a function of time. The time domain
transformation is enabled if option ZVAB-K2, Time Domain, is available .
Time domain transformation
The network analyzer measures and displays complex S-parameters and other quantities as a function
of the frequency. The measurement results can be filtered and mathematically transformed in order to
obtain the time domain representation, which often gives a clearer insight into the characteristics of the
DUT.