SetupThe Reference tab lets you configure the frequency reference for the instrument.
For Option 1ER, the user interface appears and behaves differently as shown in the sample screens below.
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GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference |
|
Initial S/W Revision |
A.01.00 |
|
Modified S/W Revision |
A.04.00 and A.11.00 |
| Modified S/W Revisions | A.04.00, A.11.00, and A.16.00 |
Standard User Interface for Reference
Option 1ER User Interface for Reference
Sets the source for the frequency reference. Choices include the following:
INTernal: Internal reference oscillator
EXTernal: External reference oscillator. Requires a signal present at the REF IN connector
External 1 Pulse Per Second (PPS): External oscillator 1 pulse per second. Requires Option 1ER and a signal present at the REF IN connector
The reference indicator field in the notifications bar at the bottom of the GUI displays the currently selected Reference Source and its current state.
When set to External, the frequency of the external signal can be specified with the External Reference Frequency setting.
If the external reference becomes unlocked or fails, after you correct the issue, toggle the Frequency Reference Source to Internal and back to External to update the Reference State status.
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GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference >Reference Source |
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SCPI Command |
[:SOURce]:ROSCillator:SOURce INTernal|EXTernal|PPS [:SOURce]:ROSCillator:SOURce? |
| SCPI Example |
:ROSC:SOUR EXT :ROSC:SOUR? |
| Dependencies | Default value of INTernal is set by Restore System Defaults. |
|
Notes |
Changing the reference may take up to 30 seconds to regain frequency lock. For remote control operation, ensure your VISA timeout is set to 30 seconds (or more) when executing this command. Without Option 1ER, attempting to set PPS will raise the error "703,Feature not supported; External PPS requires Option 1ER" |
| Couplings |
For M9383B, M9384B, M9484C: When Reference Source is External 1 PPS, Reference Source Auto is Off and unchangeable. |
| Range |
Internal | External | PPS |
| State Saved | Persistent, survives preset and power cycle but not saved in the instrument state. |
| Backwards Compatibility SCPI |
E82X7D, E8663D, and N51xxB: [:SOURce]:ROSCillator:SOURce |
| Backwards Compatibility Notes |
For N51xxB: SCPI query reports the setting’s stored value, not what is actively being applied to the hardware. This command differs from this prior behavior. To query what source is actively applied to hardware, see Current Reference Source setting. |
|
Initial S/W Revision |
A.01.00 |
|
Modified S/W Revision |
A.11.00 - Added Option 1ER A.16.00 - Added coupling with Reference Source Auto |
Remote command only.
For M9383B, M9384B, and M9484C:
Returns the current reference source being applied to the instrument. Possible sources are:
INTernal
EXTernal - External will only be applied when a signal is actively present at the REF IN connector.
External 1 Pulse Per Second (PPS). Requires Option 1ER
See the Reference Source setting for more information.
|
SCPI Command |
[:SOURce]:ROSCillator:SOURce:CURRent? |
| SCPI Example |
:ROSC:SOUR:CURR? |
|
Initial S/W Revision |
A.16.00 |
For M9383B, M9384B, and M9484C:
Enables or disables the ability of the signal generator to automatically switch between the Internal and External reference oscillator.
ON - If Auto is enabled, a valid reference signal present at the REF IN connector triggers the reference source to automatically switch from Internal to External. When the valid reference signal is absent, the instrument automatically switches from External to Internal.
OFF - If Auto is disabled, the value that you set for the Reference Source setting is used as the frequency reference source.
|
GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference > Auto |
|
SCPI Command |
[:SOURce]:ROSCillator:SOURce:AUTO ON|OFF|1|0 [:SOURce]:ROSCillator:SOURce:AUTO? |
| SCPI Example |
:ROSC:SOUR:AUTO ON :ROSC:SOUR:AUTO? |
| Dependencies | Default value of OFF is set by Restore System Defaults |
| Notes | Changing the reference may take up to 30 seconds to regain frequency lock. For remote control operation, ensure your VISA timeout is set to 30 seconds (or more) when executing this command. |
| Couplings |
For instruments with Option 1ER: When Reference Source is set to External 1 PPS, Auto is off and unchangeable. Attempting to enable will raise the error -221,“Settings Conflict; Cannot enable Auto while Reference Source is External 1 Pulse Per Second”. |
| State Saved | Persistent, survives preset and power cycle but not saved in the instrument state. |
|
Initial S/W Revision |
A.16.00 |
Sets the external reference frequency.
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GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference > External Reference Frequency |
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SCPI Command |
[:SOURce]:ROSCillator:FREQuency:EXTernal <freq> [:SOURce]:ROSCillator:FREQuency:EXTernal? |
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SCPI Example |
:ROSC:FREQ:EXT 100 MHZ |
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Preset |
This is unaffected by a Preset but is set to 10 MHz on a "Restore System Settings to Default Values." |
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State Saved |
Persistent, survives preset and power cycle but not saved in the instrument state. |
|
Notes |
Changing the reference frequency may take up to 30 seconds to regain frequency lock. For remote control operation, ensure your VISA timeout is set to 30 seconds (or more) when executing this command. For M9383B/M9384B/M9484C with Option 1ER:
For M9383B/M9384B/M9484C without Option 1ER:
|
|
Min |
Without Option 1ER: 10 MHz With Option 1ER: 1 MHz |
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Max |
Without Option 1ER: 100 MHz With Option 1ER: 110 MHz |
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Resolution |
Without Option 1ER: Not applicable With Option 1ER: 0.1 Hz |
|
Initial S/W Revision |
A.04.00 |
|
Modified S/W Revision |
A.11.00 - Added Option 1ER |
The instrument provides two locking ranges for an externally supplied reference signal. Locking range set to Wide allows your reference signal to be further away in frequency from the selected value in External Reference Frequency, with a slight compromise in the phase noise performance of the instrument. Locking range set to Narrow provides the best phase noise on the instrument. See table below.
|
Locking Range |
External Reference Requirements |
Benefits |
|---|---|---|
|
Wide |
Within approximately +/- 1.0 ppm of the selected external reference frequency |
Easier to lock to external reference |
|
Narrow |
Within approximately +/- 0.6 ppm of the selected external reference frequency |
Better phase noise |
|
GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference > External Reference Locking Range |
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SCPI Command |
[:SOURce]:ROSCillator:FREQuency:EXTernal:LRANge NARRow|WIDE [:SOURce]:ROSCillator:FREQuency:EXTernal:LRANge? |
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SCPI Example |
:ROSC:FREQ:EXT:LRAN WIDE |
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Preset |
For M9383B/M9384B: This is unaffected by a Preset but is set to NARRow on a "Restore System Settings to Default Values." For M9484C: This is unaffected by a Preset but is set to WIDE on a "Restore System Settings to Default Values." |
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State Saved |
Persistent, survives preset and power cycle but not saved in the instrument state. |
|
Notes |
For M9383B/M9384B: Beginning with S/W revision A.07.00, the default setting is NARRow. Prior to A.07.00, the instrument was configured for NARRow and not changeable. |
|
Initial S/W Revision |
A.07.00 |
Displays the current state of the frequency reference. The displayed state can help you understand whether the frequency reference is locked or if a failure occurred.
See Notifications Area for more information on various Reference states.
If the external reference becomes unlocked or fails, after you correct the issue, toggle the Frequency Reference Source to Internal and back to External to update the Reference State status.
The 10 MHz Out connector is normally on, providing a 10 MHz frequency reference by default. The connector can be switched off.
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GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference > Reference Out |
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SCPI Command |
:ROUTe[:CONNectors]:REFerence:ROUTput OFF|F10 :ROUTe[:CONNectors]:REFerence:ROUTput? |
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SCPI Example |
ROUT:REF:ROUT OFF |
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Notes |
For M9383B, M9384B, and M9484C: Can be F10 (10 MHz) or OFF. Attempting other selections on these models will raise the error 703,"Feature not supported; Reference Output frequency not changeable on this instrument." |
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Preset |
This is unaffected by a Preset but is set to 10 MHz on a "Restore System Settings to Default Values." |
| Range | OFF | 10 MHz |
|
State Saved |
Persistent, survives preset and power cycle but not saved in the instrument state. |
|
Initial S/W Revision |
A.13.00 |
For M9383B or M9384B, when checked this turns on the 100 MHz Out reference output signal. Leave this unchecked if you are not using this output, to minimize emissions.
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GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference > 100 MHz Out |
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SCPI Command |
:ROUTe[:CONNectors]:REFerence:LFOutput:STATe ON|OFF|1|0 :ROUTe[:CONNectors]:REFerence:LFOutput:STATe? |
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Notes |
For models other than M9383B or M9384B the setting is accepted with no error raised. |
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Preset |
On |
|
Initial S/W Revision |
A.01.00 |
For M9383B or M9384B, when checked this turns on the 19.2 GHz Out reference output signal. Leave this unchecked if you are not using this output, to minimize emissions.
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GUI Location |
System Menu (triple bar icon) > Settings (gear icon) > Reference > 19.2 GHz Out |
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SCPI Command |
:ROUTe[:CONNectors]:REFerence:HFOutput:STATe ON|OFF|1|0 :ROUTe[:CONNectors]:REFerence:HFOutput:STATe? |
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Notes |
For models other than M9383B or M9384B the setting is accepted with no error raised. |
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Preset |
Off |
|
Initial S/W Revision |
A.01.00 |