Concepts and features
R&S
®
ZNA
234
User Manual 1178.6462.02 ─ 20
4.7.3
Frequency conversion measurements
Option R&S
ZNA-K4
With option R&S
ZNA-K4, the frequencies of the source ports can be configured inde-
pendently. The source and receive frequencies of the ports are always equal. Arbitrary
port settings represent a major extension to the analyzer's measurement functionality;
in particular they allow you to measure frequency-converting DUTs.
The following figure shows a transmission measurement on a mixer.
VNA
1
2
RF
LO
IF
f
IF, up
= f
RF
+ f
LO
f
IF, down
= | f
RF
- f
LO
|
In this example, the transmission parameter S
21
corresponds to the mixer's conversion
gain.
Before measuring, the port frequencies must be set appropriately. In the port configura-
tion table (Channel – [Channel
Config] > "Port Config" > "Port Settings..." > "Arb Fre-
quency"), the (source) frequency of Port 1 is set to the desired RF frequency (here: the
channel base frequency/sweep range f
b
). An external generator provides a fixed stimu-
lus signal at 1 GHz. To measure the up-converted IF signal, the (receive) frequency at
Port 2 is set to f
b
+ 1 GHz.
Independent source powers for Port 1 and Gen1 can be configured in addition, if so
desired.
Optional extensions and accessories
