VNA concepts and features
R&S
®
ZNL/ZNLE
224
User Manual 1178.5966.02 ─ 19
In contrast to S-, Z- and Y-parameters, wave quantities and ratios are not system-error
corrected.
To increase the accuracy or to correct a possible attenuation in the source signal path,
it is recommended to perform a power calibration (R&S
9.3.5.1
Wave quantities
A wave quantity measurement provides the power of any of the transmitted or received
waves. The power can be displayed in voltage units (e.g. V or dBmV) or equivalent
power units (e.g. W or dBm).
Examples for using wave quantities
The wave quantities provide the power at the different receive ports of the analyzer.
This is different from an S-parameter measurement, where the absolute power of a lin-
ear device is canceled. Wave quantities are therefore suitable for the following mea-
surement tasks:
●
Analysis of nonlinearities of the DUT.
●
Use of the analyzer as a selective power meter.
To increase the accuracy or to correct a possible attenuation in the source signal
path, it is recommended to perform a power calibration (R&S
ter 9.5.6, "Scalar power calibration"
The notation for wave quantities is as follows:
●
"a
i
Src Port j" denotes the wave incoming at DUT port i, when DUT port j is stimula-
ted.
a
i
is detected at the reference receiver of the VNA port connected to DUT port i.
●
"b
i
Src Port j" denotes the wave outgoing at DUT port i, when DUT port j is stimula-
ted.
b
i
is detected at the measurement receiver of the VNA port connected to DUT port
i.
In a standard forward S-parameter measurement, a
1
Src Port 1 is the incident wave
and b
1
Src Port 1 is the reflected wave at DUT port 1.
9.3.5.2
Ratios
A ratio measurement provides the complex ratio of any combination of transmitted or
received wave amplitudes. Ratios complement the S-parameter measurements, where
only ratios of the form b
i
/a
j
(ratios between outgoing and incoming waves at the DUT
ports) are considered.
Measurement results
