Rohde & Schwarz R&S ZVA 8 - Wave Quantities; Ratios

R&S
®
ZVA/ZVB/ZVT Measured Quantities
1145.1084.12 3.31 E-1
as the assumption of linearity holds, the S-, Z- and Y-parameters are independent of the source power.
The network analyzer provides two additional sets of measurement parameters which have a
unambiguous meaning even if the DUT is measured outside its linear range:
• Wave Quantities provide the power of any of the transmitted or received waves.
• Ratios provide the complex ratio of any combination of transmitted or received wave amplitudes.
In contrast to S-, Z- and Y-parameters, wave quantities and ratios are not system-error
corrected.
Wave Quantities
A wave quantity measurement provides the power of any of the transmitted or received waves. The
power can be displayed in voltage (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 linear device is cancelled. Wave
quantities are therefore suitable for the following measurement tasks:
• Analysis of non-linearities of the DUT.
• Use of the analyzer as a selective power meter.
The notation for wave quantities includes the direction and the test port number. Additionally, the
source port must be specified. The letter a indicates a transmitted wave, b a received wave.
Examples:
• a1 Src Port 1 is the outgoing wave at test port 1. In a standard S-parameter measurement, this
wave is fed to the input port (port 1) of the DUT (forward measurement).
• b1 Src Port 1 is the incoming wave at test port 1. In a standard S-parameter measurement, this is
the reflected wave at port 1 of the DUT (forward measurement).
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
(ratio of the incoming wave to the outgoing wave at the test ports i and j of the DUT) are considered.
Examples for using ratios
A measurement of ratios is particularly suitable for the following test scenarios:
• The test setup or some of its components (e.g. active components or non-reciprocal devices) do
not allow a system error correction so that a complete S-parameter measurement is not possible.
• The test setup contains frequency-converting components so that the transmitted and the