Measurements | Operation Verification |
Reference Oscillator Aging Rate (Optional)
The following test can be used to verify that the MS2781B 10 MHz Reference Oscillator is within its aging specification. The instrument derives its frequency accuracy from an internal 10 MHz crystal oscillator standard. An inherent characteristic of crystal oscillators is the effect of crystal aging within the first few days to weeks of operation. Typically, the frequency of the crystal oscillator increases slightly at first, then settles to a relatively constant value for the rest of its life.
Note: Do not confuse crystal aging with other short term frequency instabilities, for example, noise and temperature. The internal time base of the instrument may not achieve its specified aging rate before the specified
For the greatest absolute frequency accuracy, allow the MS2781B to warm up until its output frequency has stabilized (usually 7 to 30 days). Once stabilized, the change in reference oscillator frequency should remain within the aging rate if (1) the reference oscillator oven is not allowed to cool, (2) the instrument orientation with respect to the earth's magnetic field is maintained, (3) the instrument does not sustain any mechanical shock, and (4) ambient temperature is held constant. This test should be performed upon receipt of the instrument and again after a period of several days to weeks to fully qualify the aging rate.
Test Setup
Connect the MS278XB rear panel 10 MHz Reference Out to the Symmetricom model
Figure 5-48. Equipment Setup for Internal Reference Oscillator Aging Rate Tests
MS278XB OM |
