Internal Imebase: Aging Rate - Agilent Technologies 83620A Service Manual

1. Internal Timebase: Aging Rate
Description and Procedure
his procedure checks the accuracy of the internal timebase. he time required
for a speci c phase change is measured both before and after a speci ed
waiting period. he aging rate is inversely proportional to the absolute value of
the di erence in the measured times.
he overall accuracy of the internal timebase is a function of:
6 6 6
TBC AR TE LE
TBC = timebase calibration
TE = temperature effects
AR = aging rate
LE = line effects
After the timebase is adjusted, the timebase frequency should stay within the
aging rate if the following things happen:
he timebase oven does not cool down.
he instrument keeps the same orientation with respect to the earth's
magnetic eld.
he instrument stays at the same altitude.
he instrument does not receive any mechanical shock.
If the timebase oven cools (the instrument is disconnected from AC power),
you may have to readjust the timebase frequency after a new warmup cycle.
ypically, however, the timebase frequency returns to within
original frequency.
he internal timebase can be tested after reconnecting AC
Note
power for 10 minutes, but for best accuracy, test again after the
instrument has been on or in standby condition for 24 hours.
2-8 Performance Tests
Internal Timebase: Aging Rate
All manuals and user guides at all-guides.com
where:
6
1 Hz of the
HP 8360