R&S FSW Series, User Manual

Page: 701 / 1450

General Instrument Setup
R&S
®
FSW
701 User Manual 1173.9411.02 ─ 43
The default setting is the internal reference. When an external reference is used, EXT
REF is displayed in the status bar.
The following reference inputs are available:
Table 12-2: Available Reference Frequency Input
Setting Source Connector Frequency Tuning
Range
Loop Band-
width Description
Internal (OCXO) 10 MHz - 1-100 Hz Internal reference signal
or optional OCXO
External Reference
10
MHz
REF INPUT
1..50
MHz
10 MHz +/- 6 ppm 1-100 Hz Fixed external 10 MHZ reference fre-
quency
Good phase noise performance
External Reference
1..50MHz REF INPUT
1..50
MHz
1..50 MHz
in 1
Hz
steps
+/- 0.5 ppm 0.1 Hz (fixed) Variable external reference frequency
in 1
Hz steps
Good external phase noise suppres-
sion. Small tuning range.
+/- 6 ppm 1-30 Hz Variable external reference frequency
in 1
Hz steps
Wide tuning range.
External Reference
100
MHz
REF INPUT
100
MHz / 1 GHz
100 MHz +/- 6 ppm 1-300 Hz External reference
Good phase noise performance
External Reference
1
GHz
REF INPUT
100
MHz / 1 GHz
1 GHz +/- 6 ppm 1-300 Hz External reference
Sync Trigger SYNC TRIGGER
INPUT 100 MHz +/- 6 ppm 1-300 Hz External reference
Remote command:
[SENSe:]ROSCillator:SOURce
on page 1260
SOURce<si>:EXTernal<ext>:ROSCillator:EXTernal:FREQuency
on page 1260
Behavior in case of missing external reference ← Reference Frequency Input
If an external reference is selected but none is available, there are different ways the
instrument can react.
"Show Error
Flag" The error message "External reference missing" is displayed if no
valid external reference signal is available. Additionally, the flag "NO
REF" is displayed to indicate that no synchronization was performed
for the last measurement .
"Switch to
internal refer-
ence" The instrument automatically switches back to the internal reference
if no external reference is available. Note that you must re-activate
the external reference if it becomes available again at a later time.
Remote command:
[SENSe:]ROSCillator:SOURce
on page 1260
[SENSe:]ROSCillator:SOURce:EAUTo?
on page 1261
Reference Frequency Settings