R&S FSW Series User Manual

General Instrument Setup
R&S
®
FSW
702User Manual 1173.9411.02 ─ 43
Tuning Range ← Reference Frequency Input
The tuning range is only available for the variable external reference frequency. It
determines how far the frequency may deviate from the defined level in parts per mil-
lion (10
-6
).
"+/- 0.5 ppm"
With this smaller deviation a very narrow fixed loop bandwidth of 0.1
Hz is realized. With this setting the instrument can synchronize to an
external reference signal with a very precise frequency. Due to the
very narrow loop bandwidth, unwanted noise or spurious components
on the external reference input signal are strongly attenuated. Fur-
thermore, the loop requires about 30 seconds to reach a locked state.
During this locking process, "NO REF" is displayed in the status bar.
"+/- 6 ppm"
The larger deviation allows the instrument to synchronize to less pre-
cise external reference input signals.
Remote command:
[SENSe:]ROSCillator:TRANge on page 1262
Frequency ← Reference Frequency Input
Defines the external reference frequency to be used (for variable connectors only).
Loop Bandwidth ← Reference Frequency Input
Defines the speed of internal synchronization with the reference frequency. The setting
requires a compromise between performance and increasing phase noise.
For a variable external reference frequency with a narrow tuning range (+/- 0.5 ppm),
the loop bandwidth is fixed to 0.1 Hz and cannot be changed.
Remote command:
[SENSe:]ROSCillator:LBWidth on page 1259
Reference Frequency Output
A reference frequency can be provided by the R&S FSW to other devices that are con-
nected to this instrument. If activated, the reference signal is output to the correspond-
ing connector.
"Output 100 MHz"
Provides a 100 MHz reference signal to the REF OUTPUT 100 MHz
connector.
"Output 640 MHz"
Provides a 640 MHz reference signal to the REF OUTPUT 640 MHz
connector.
"Output Sync Trigger"
Provides a 100 MHz reference signal to the SYNC TRIGGER OUT-
PUT connector.
Remote command:
[SENSe:]ROSCillator:O640 on page 1259
[SENSe:]ROSCillator:OSYNc on page 1260
Resetting the Default Values
The values for the "Tuning Range", "Frequency" and "Loop Bandwidth" are stored for
each source of "Reference Frequency Input".
Reference Frequency Settings

R&S FSW Series Specifications

General

Brand	R&S
Model	FSW Series
Category	Measuring Instruments
Language	English