Concepts and Features
R&S
®
ZNB/ZNBT
198
User Manual 1173.9163.02 ─ 53
C
G
R
L
Balun
Differential Matching Network
In contrast to standard balanced embedding (4-port), the matching circuit is only
applied to the differential mode port (2-port). It can be specified via a Touchstone s2p
file or by parametrizing a lumped "Shunt L, Shunt C" element model.
5.6.2.9
Fixture Modeling and Deembedding
When performing tasks such as verifying digital high-speed signal structures on printed
circuit boards (PCBs), measurements have to be carried out on certain layers without
the effects of probes, probe pads, vias, lead-ins and lead-outs. This requires the use of
accurate deembedding algorithms to calculate and remove these effects from the mea-
surements, leaving only the result for the area of interest.
Instead of asking the user to define the fixture by parametrizing one of the given lum-
ped circuit models or by "somehow" providing a suitable
sNp
file, the firmware of the
R&S
ZNB/ZNBT now also provides integration for third-party tools that model the test
fixture from measured data:
●
AtaiTec's
In Situ De-Embedding
(ISD), see
http://ataitec.com/products/isd/
●
PacketMicro's
Smart Fixture De-embedding
(SFD) Tool, see
cro.com/Products/sfd-tool.html
More such fixture modeling tools may be added in future releases of the R&S
ZNB/
ZNBT firmware.
The tools must be installed on the VNA.
Test Setup
The setup below shows an example for verifying the high-speed differential signal lines
on a PCB.
Offset Parameters and De-/Embedding
