R&S ZNB Series User Manual page 142

®
R&S ZNB/ZNBT
–
–
●
DUT with balanced logical ports i and j:
–
–
Differential Imbalance
A (differential) imbalance can also be calculated if the second balanced DUT port is
connected to two single-ended logical ports:
Logical port i
(balanced)
Physical port a
Physical port b
Imb
jk-i
Imb
i-jk
4.3.7 Stability factors
The stability factors K, μ1 and μ2 are real functions of the (complex) S-parameters,
defined as follows:

K :


:
1


:
2
where
User Manual 1173.9163.02 ─ 62
Logical port i
(single-ended)
Physical port a
Imb = –S /S and Imb
ji ca da
CMRR = S /S and CMRR
ji dsji csji
Logical port i
(balanced)
Physical port a
Log.
NWA
port
Physical port b
Imb = –(S – S )/(S
ji ca cb
CMRR =S /S
ji ddji ccji
Log.
Balanced
NWA
port
= –(S – S )/(S – S
ca da cb db
= –(S – S )/(S – S
ac ad bc bd
 
2 2
1 | S | | S |
11 22

| 2

1 |
   
| S S ( S S
22 11 11 22

1
  
| S S ( S S
11 22 11 22
denotes the complex conjugate of S.
DUT
Single-
Balanced
ended
port
port
= –S /S
ij ac ad
= S /S
ij sdij scij
DUT
Balanced Balanced
port port
– S ), for i≠j
da db
DUT
Balanced
port port
)
)
   
| S S S
11 22 12

S S |
12 21
2
S |
11
  
S S | ) | S S
12 21 12 21
2
| S |
22
   
S S | ) | S S
12 21 12 21
Concepts and features
Measurement results
Logical port j
(balanced)
Physical port c
Log.
NWA
port
Physical port d
Logical port j
(balanced)
Physical port c
Log.
NWA
port
Physical port d
Logical ports j,k
(single-ended)
Physical port c
Physical port d
2
S |
21
|
|
142