Initial accuracy, temperature stability, aging and holdover must be separate rows in the frequency-error budget because they describe different mechanisms and time intervals. Initial accuracy applies after a stated warm-up and calibration condition. Temperature stability applies over a defined profile. Aging needs an elapsed interval. Holdover begins when a reference is lost and depends on prior lock history and environment.
Reject a single ppm figure that does not say whether terms are maximum, typical, additive or statistically combined. Also separate supply and load sensitivity, vibration, retrace after power interruption and warm-up. For precision timing, state the observation interval and statistic used; Allan deviation at one averaging time cannot replace a maximum frequency-error limit over an unrelated interval.
The project must provide carrier or clock frequency, allowable accumulated phase or time error, temperature and vibration profile, calibration interval, reference-loss duration and recovery behavior. Acceptance evidence should retain the environmental profile, measurement interval, reference history, frequency record and uncertainty.