Concepts and features
R&S
®
ZNB/ZNBT
136
User Manual 1173.9163.02 ─ 62
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.
4.3.5.2
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.
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-recipro-
cal 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 received waves are at different frequencies.
●
A ratio of two arbitrary waves that is not an element of the S-matrix (e.g. a ratio of
the form a
i
/a
j
) is needed.
The notation for ratios is similar to the notation for wave quantities (see
ter 4.3.5.1, "Wave quantities"
on page 135). Given a source port k, any ratio between
wave quantities "a
i
Src Port k" and "b
j
Src Port k" can be measured.
Examples:
●
"b
2
/a
1
Src Port 1" is the ratio of the outgoing wave at DUT port 2 and the incident
wave at DUT port 1 (i.e. DUT port 1 ist stimulated). This corresponds to the forward
transmission coefficient S
21
.
●
"b
1
/a
1
Src Port 1" is the ratio of the outgoing wave at DUT port 1 and the incident
wave at DUT port 1 (i.e. DUT port 1 ist stimulated). This corresponds to the forward
reflection coefficient S
11
.
4.3.5.3
Detector settings
The "Detector" settings select the algorithm that is used to calculate the displayed
measurement points from the raw data. The "Detector" can be selected in the "More
Wave Quantities" and More Ratios dialogs.
Measurement results
