R&S ZNB - 5.3.7 Stability Factors

Concepts and Features
R&S
®
ZNB/ZNBT
131User Manual 1173.9163.02 ─ 55
DUT
Balanced
port
Log.
NWA
port
Single-
ended
port
Physical port c
Logical port j
(balanced)
Physical port d
Logical port i
(single-ended)
Physical port a
– Imb
ji
= –S
ca
/S
da
and Imb
ij
= –S
ac
/S
ad
– CMRR
ji
= S
dsji
/S
csji
and CMRR
ij
= S
sdij
/S
scij
●
DUT with balanced logical ports i and j:
DUT
Balanced
port
Log.
NWA
port
Balanced
port
Log.
NWA
port
Physical port c
Logical port j
(balanced)
Physical port d
Logical port i
(balanced)
Physical port a
Physical port b
– Imb
ji
= –(S
ca
– S
cb
)/(S
da
– S
db
), for i≠j
– CMRR
ji
=S
ddji
/S
ccji
Differential Imbalance
A (differential) imbalance can also be calculated if the second balanced DUT port is
connected to two single-ended logical ports:
DUT
Balanced
port
Balanced
port
Log.
NWA
port
Physical port c
Logical ports j,k
(single-ended)
Physical port d
Logical port i
(balanced)
Physical port a
Physical port b
Imb
jk-i
= –(S
ca
– S
da
)/(S
cb
– S
db
)
Imb
i-jk
= –(S
ac
– S
ad
)/(S
bc
– S
bd
)
5.3.7 Stability Factors
The stability factors K, μ1 and μ2 are real functions of the (complex) S-parameters,
defined as follows:
||2
||||||1
:
2112
2
21122211
2
22
2
11
SS
SSSSSS
K



|||)(|
||1
:
2112211222111122
2
11
1
SSSSSSSS
S


 
|||)(|
||1
:
2112211222112211
2
22
2
SSSSSSSS
S


 
where denotes the complex conjugate of S.
Measurement Results