Performance Tests and Calibration 7
Agilent U1251A/U1252A User’s and Service Guide 123
warranted beyond the 1- year calibration interval. Agilent 
does not recommend extending calibration intervals beyond 
2 years for any application.
Adjustment is Recommended
Specifications are only guaranteed within the period stated 
from the last adjustment. Whatever calibration interval you 
select, Agilent recommends that complete re- adjustment 
should always be performed at the calibration interval. This 
will assure that the U1251A/U1252A will remain within the 
specifications for the next calibration interval. This criterion 
for the re- adjustment provides the best long–term stability. 
Performance data are measured during the Performance 
Verification Tests but this does not guarantee that the 
instrument will remain within these limits unless the 
adjustments are performed.
Refer to the section “To Read the Calibration Count” on 
page 153 and verify that all the adjustments have been 
performed.