Common Measurement Settings
R&S
®
FSW
340
User Manual 1173.9411.02 ─ 19
TTL synchronization
Some Rohde
&
Schwarz signal generators support TTL synchronization when connec-
ted via GPIB. The TTL interface is included in the AUX CONTROL connector of the
R&S
FSW-B10 option.
When pure GPIB connections are used between the R&S
FSW and the signal genera-
tor, the R&S
FSW sets the generator frequency for each frequency point individually
via GPIB, and only when the setting procedure is finished, the R&S
FSW can measure
the next sweep point.
For generators with a TTL interface, the R&S
FSW sends a list of the frequencies to be
set to the generator before the beginning of the first sweep. Then the R&S
FSW starts
the sweep and the next frequency point is selected by both the R&S
FSW and the gen-
erator using the TTL handshake line "TRIGGER". The R&S
FSW can only measure a
value when the generator signals the end of the setting procedure via the "BLANK"
signal.
Using the TTL interface allows for considerably higher measurement rates than pure
GPIB control, because the frequency stepping of the R&S
FSW is directly coupled with
the frequency stepping of the generator.
Reverse sweep
The frequency offset for automatic coupling can be used to sweep in the reverse direc-
tion. To do so, define a negative offset in the external generator measurement configu-
ration. (Note that the frequency is defined as the unsigned value of the equation, thus a
negative frequency is not possible.)
Example: Example for reverse sweep
F
AnalyzerStart
= 100 MHz
F
AnalyzerStop
= 200 MHz
F
Offset
= -300 MHz
Numerator = Denominator = 1
→
F
GeneratorStart
= 200 MHz
→
F
GeneratorStop
= 100 MHz
If the offset is adjusted so that the sweep of the generator crosses the minimum gener-
ator frequency, a message is displayed in the status bar ("Reverse Sweep via min. Ext.
Generator Frequency!").
Data Input and Output
