Rohde & Schwarz ESW Series - Page 332

General Instrument Setup
R&S
®
ESW
332User Manual 1177.6298.02 ─ 08
Reference Frequency Input
The R&S ESW can use the internal reference source or an external reference source
as the frequency standard for all internal oscillators. A 10 MHz crystal oscillator is used
as the internal reference source. In the external reference setting, all internal oscillators
of the R&S ESW are synchronized to the external reference frequency.
External references are connected to one of the REF INPUT or the SYNC TRIGGER
connectors on the rear panel. For details see the "Getting Started" manual.
Note: The optional, and more precise OCXO signal can replace the internal reference
source.
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 13-2: 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..20 MHz
10 MHz +/- 6 ppm 1-100 Hz Fixed external 10 MHZ reference fre-
quency
Good phase noise performance
External Reference
1..20 MHz
REF INPUT
1..20 MHz
1..20 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 100 MHz +/- 6 ppm 1-300 Hz External reference
Good phase noise performance
Sync Trigger SYNC TRIGGER
INPUT
100 MHz +/- 6 ppm 1-300 Hz External reference
Remote command:
[SENSe:]ROSCillator:SOURce on page 623
SOURce<si>:EXTernal<ext>:ROSCillator:EXTernal:FREQuency
on page 623
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.
Reference Frequency Settings