R&S ZNB Series - Page 237

Concepts and features
R&S
®
ZNB/ZNBT
237User Manual 1173.9163.02 ─ 62
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.
Internal Second Source
If an internal second source is available, the mixer measurements outlined above (and
many other measurements) can be performed without an additional external generator;
see Chapter 4.7.14, "Internal second source", on page 255. However, be aware of the
limited source connectivity (described there).
Optional extensions and accessories