According to techniques disclosed herein, a Tactical Data Link (TDL) terminal uses a first clock that runs during a sleep mode for initial realignment of a second clock that is used for synchronous operation with respect to a TDL network during active-mode operation of the TDL terminal. For example, implementation of the first clock via low-power circuitry and characterization of the relative error or drift of the first clock with respect to the second clock allows the TDL terminal to adjust the phase of the second clock upon transitioning back to active-mode operation, for accurate realignment of the second clock with the TDL network timing.