: Instrument Operation : Reference Status Conditions
 
Reference Status Conditions
This section describes the reference source types and lock condition indicators. The status conditions depend on the options installed.
Reference Oscillator Current Source
The title bar displays the source that is determining the RF output accuracy as described below:
REF EXT 1600
1600 MHz external
REF EXT 100
100 MHz external
REF EXT 1PPS
1PPS external
REF EXT 10
10 MHz external
REF INT RB
Internal 10 MHz Rubidium clock, Ultra Stable Rubidium Reference (Option 3) only.
REF INT 10
Internal 10 MHz free running, Low Phase Noise and Ultra High Stability (Option 3) only.
REF INT 100
Internal100 MHz free running.
Note: For EXT 1PPS, EXT 10, or INT RB, the value may contain “Acquiring” instead of “REF” while the system is in the process of acquiring lock to this reference.
Reference Oscillator Lock Status
The reference oscillation lock condition is described below.
10 MHz Locked:
Indicates the internal 10 MHz is locked to either an internal or external reference.
100 MHz Locked
100 MHz can only be locked to the 10 MHz (Option 3).
Acquiring
Attempting to acquire lock to the reference source indicated by Low Phase Noise and Ultra High Stability (Option 3); or, attempting to acquire lock to an external 10 MHz reference when Low Phase Noise and Ultra High Stability (Option 3 is not installed).
Locked External
100 MHz reference is locked to an external 10 MHz reference and Low Phase Noise and Ultra High Stability (Option 3 is not installed); or, 10 MHz reference is locked to an external reference, either 10 MHz or 1PPS with Low Phase Noise and Ultra High Stability (Option 3).
Locked Rubidium
10 MHz reference is locked to an internal Rb reference Ultra Stable Rubidium Reference (Option 56).
Free Running
100 MHz reference is free running Low Phase Noise and Ultra High Stability (Option 3 is not installed); or, 10 MHz reference is free running Low Phase Noise and Ultra High Stability (Option 3).
Error External
100 MHz reference can't lock to a connected external 10 MHz input Low Phase Noise and Ultra High Stability (Option 3 not installed): or, 10 MHz reference can't lock to a connected external reference, either 10 MHz or 1PPS (Low Phase Noise and Ultra High Stability (Option 3).
Error Rubidium
10 MHz reference can't lock to the internal Rb reference Ultra Stable Rubidium Reference (Option 56) installed.
Error GPS
10 MHz reference can't lock to the internal GPS reference 1PPS. GNSS/GPS Atomic Clock Receiver (Option 66).
 
Reference Oscillator 100 MHz Lock Status
The 100 MHz reference lock status is described below:
Acquiring
Attempting to lock the 100 MHz to an external 10 MHz reference. Low Phase Noise and Ultra High Stability (Option 3); or, attempting to lock the 100 MHz to the internal 10 MHz reference. Low Phase Noise and Ultra High Stability (Option 3)
Locked
100 MHz is locked to the external 10 MHz. Low Phase Noise and Ultra High Stability (Option 3 is not installed); or, 100 MHz is locked to the internal 10 MHz reference. Low Phase Noise and Ultra High Stability (Option 3).
Free
100 MHz is free running
Error
100 MHz is unable to lock to a connected 10 MHz. Low Phase Noise and Ultra High Stability (Option 3 is not installed); or, 100 MHz is unable to lock to the internal 10 MHz reference, Low Phase Noise and Ultra High Stability (Option 3).
Reference Oscillator GPS Lock Status
Requires GNSS/GPS Atomic Clock Receiver (Option 66). The GPS reference 1PPS lock status is described below:
Locked
The GNSS reference is locked
Acquiring
The GPS reference is acquiring lock
Off
The GPS module in turned off
Error
The GPS reference is unable to acquire lock
Reference Oscillator Rubidium Lock Status
Requires Low Phase Noise and Ultra High Stability (Option 3) and Ultra Stable Rubidium Reference (Option 56). The Rubidium reference lock status is described below:
Locked
The Rb internal TCXO is locked to the vapor chamber.
Acquiring
The Rb internal TCXO is acquiring lock to the vapor chamber.
Error
The Rb internal TCXO is unable to acquire lock to the vapor chamber.