256 Chapter 4
Instrument Functions: P - Z
System
Instrument Functions: P - Z
alerted that alignments are needed.
•Off, the instrument won’t initiate any* visible alignments or alerts.
•All, turns on the automatic alignment of all measurement systems. When Auto Align,All is
selected, “AA” appears along the left edge of the display.
•Alert, a 3 degree (Celsius) temperature change or a time span of 24 hours since the last
successful Full alignment (e.g., Align All Now) will trigger an alert that alignments
need to be done, but no alignments will be performed without user input. When Auto
Align Alert is selected “AL” appears along the left edge of the display.
•All but RF, turns on the automatic alignment of all measurement systems except the RF
section. (Eliminating automatic alignment of the RF prevents changes in the input
impedance between sweeps, which could cause input device instability.) When Auto Align,
All but RF is selected, “AB” appears along the left edge of the display.
•On, the instrument behaves like the Alert, but will automatically perform a full
alignment when it is needed. In addition, every 15 minutes passing or 1.5 degrees
temperaturechangewillcausejusttheRFsystemgaintobealigned,toachievethebest
absolute amplitude accuracy. For either alignment, the instrument will stop any
measurement currently in process, perform the full alignment, then restart the
measurement from the beginning (similar to pressing Restart). If any alignment FAILs
or is ABORTed by the user (e.g. ESCape key), the instrument will wait 5 minutes before
retrying the necessary alignment. This helps to avoid infinite recursive loops of
alignment behavior in the event of broken hardware. Also see “Align All Now” on page 257.