Concepts and features
R&S
®
ZND
125
User Manual 1173.9557.02 ─ 61
General Definition
In general, imbalance and CMRR are quantities with two numeric indices, indicating
the logical output port and the logical input port of the DUT during the measurement
(Imb
<out><in>
, CMRR
<out><in>
).
●
DUT with single-ended logical port i and balanced logical port j:
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
)
4.3.7
Stability factors
The stability factors K, μ1 and μ2 are real functions of the (complex) S-parameters,
defined as follows:
|
|
2
|
|
|
|
|
|
1
:
21
12
2
21
12
22
11
2
22
2
11
S
S
S
S
S
S
S
S
K
Measurement results
www.allice.de
Allice Messtechnik GmbH