Agilent Technologies Agilent 33500 Series

ROSCillator Subsystem
ROSCillator Subsystem
The ROSCillator subsystem controls use of the 10 MHz reference oscillator and external reference oscillator input. The
reference oscillator is the primary clock for all waveform synthesis. All waveforms are phase-locked to the reference
oscillator, which therefore controls output signal frequency and phase.
l ROSCillator:SOURce - selects internal or external reference oscillator source
l ROSCillator:SOURce:AUTO - disables or enables automatic selection of reference oscillator signal source
l ROSCillator:SOURce:CURRent? - returns INT or EXT to indicate current reference oscillator source
ROSC:SOURce sets ROSCillator:SOURce:AUTO to OFF, and ROSCillator:SOURce:AUTO ON overrides ROSC:SOURce. The
more recent command (of these two) takes priority.
ROSCillator:SOURce:AUTO ON uses the instrument's internal oscillator as the reference oscillator. This may be either
standard Temperature Compensated Crystal Oscillator (TCXO) or the optional Ovenized Crystal Oscillator (OCXO).
See *OPT? for details on determining whether OCXO is installed. If an external 10 MHz reference signal is on the rear-
panel 10MHzIn connector, the instrument uses the external signal. An icon also appears at the top right corner of
the display to indicate the reference source change.
ROSCillator:SOURce {INTernal|EXTernal}
ROSCillator:SOURce?
Selects the source for the reference oscillator used as the frequency/phase reference for signals generated by the
instrument.
Parameter Typical Return
{INTernal|EXTernal},defaultINT INT or EXT
Use the external reference oscillator source:
ROSC:SOUR EXT
l EXTernal:instrument uses signal on the rear-panel 10 MHz In connector as reference, and generates an error if
this signal is absent or the instrument cannot lock to it. In such error cases, instrument output continues, but the
frequency will be unstable.
l INTernal: instrument uses the internal reference oscillator and ignores the signal at the 10 MHz In connector.
ROSCillator:SOURce:AUTO {ON|OFF}
ROSCillator:SOURce:AUTO?
Disables or enables automatic selection of the reference oscillator.
Parameter Typical Return
{ON|OFF},defaultON ONor OFF
Select reference source automatically:
ROSC:SOUR:AUTO ON
Agilent 33500 Series Operating and Service Guide 281