268 Chapter 4
Instrument Functions: P - Z
System
Instrument Functions: P - Z
4.8.6 Reference
Displays functions that control the external frequency reference.
Key Path: System
Remote Command:
There is no remote command for this key.
4.8.6.1 Freq Ref
Specifies the frequency reference as being internal or external. If the frequency reference
is specified as internal, the frequency of the reference is automatically identified as being
10 MHz. If the frequency reference is specified as external, you must enter the frequency of
the external reference being used. If External Reference is selected, Ext Ref will appear
on the right side of the display.
The frequency of an external frequency reference is not automatically detected. If an
external frequency source is selected, the frequency of the source must be entered.
If Ext is selected, and you press Freq Ref, Ext will remain selected and the Ext reference
frequency will become the active function. If Freq Ref is pressed again, Int will become
selected (at 10 MHz). The Ext reference frequency is remembered and will be used again if
Ext is selected.
If the external reference is missing or out of range, or the frequency reference is unlocked,
the message “External reference missing or out of range”, will appear on the
display.
Key Path: System,Reference
State Saved: Not Saved in Instrument State. Neither the external reference frequency
nor the state of this function (Int or Ext) are affected by factory preset or
power cycle. Reset to the factory default (Int, 10 MHz) by pressing System,
Restore Sys Defaults.
Default: Internal, 10 MHz
Range: 1 MHz to 30 MHz
Remote Command:
[:SENSe]:ROSCillator:SOURce INTernal|EXTernal
[:SENSe]:ROSCillator:SOURce?
[:SENSe]:ROSCillator:EXTernal:FREQuency <value>
[:SENSe]:ROSCillator:EXTernal:FREQuency?
Example: Before switching to the external reference source, specify the frequency of
the external reference that you plan to use.
ROSC:EXT:FREQ 20 MHz sets the external reference frequency to 20 MHz,