Rohde & Schwarz R&S SMW200A - Local Oscillator Coupling

Configuring the RF Signal
R&S
®
SMW200A
482User Manual 1175.6632.02 ─ 30
Ref. Frequency Source = e.g., Rohde & Schwarz signal analyzer
f
Ref
= 10 MHz, 100 MHz, 1 MHz to 100 MHz, 1 GHz** external reference frequency
** = 1 GHz uses REF IN 1 GHz connector
REF IN, REF OUT = Connectors
1 GHz, 1 MHz to 100 MHz at connector REF IN 1 GHz/REF IN and 10 MHz at REF
OUT
●
E.g., external Ref. f
ref
= 100 MHz
●
Source = "External"
●
External Reference Frequency = "100 MHz"
●
Reference Output/1 GHz Reference Output = "10 MHz"
●
Synchronization Bandwidth = "Narrow"
8.6 Local Oscillator Coupling
The "LO Coupling" function allows a distribution of the local oscillator signal in a way
that multiple RF signals can be derived from the same LO signal. This is mandatory for
minimizing the phase fluctuations between these RF signals.
The R&S SMW uses either the internal oscillator frequency for the LO signal, that is
the output signal of the internal synthesizer, or an external frequency source. You can
select the internal or external LO signal of path A, and optionally couple it with path B.
Uncoupled, B uses its internal signal. When the LO signal is coupled, the R&S SMW
indicates the connection line in the block diagram.
Connectors
●
The internal LO signal is output at the LO OUT connector.
●
An external signal is fed in at the LO IN connector.
See also "To find the physical Location of the LO In/Out connectors" on page 487.
LO coupling possibilities
You can couple the LO signal as follows:
●
"A Internal & A -> B Coupled"
The R&S SMW uses the internal oscillator signal of path A also in path B.
The reference frequency settings in path B have no effect and are thus disabled for
editing.
●
"A External & A -> B Coupled"
The R&S SMW receives an external oscillator signal and uses this signal in both
paths.
The reference frequency settings in both paths have no effect and are thus dis-
abled for editing.
Similarly, you can couple the signals of cascaded instruments as shown in "To con-
figure LO coupling with cascaded instruments to achieve phase coherence"
on page 487.
Local Oscillator Coupling