Timing uncertainty in a curvature-based current-sign certificate adds the effect of uncertain sample and decision times to a bound on extrapolated electric current. Two accurate readings do not identify a future current precisely unless their timing relative to that future instant is also bounded. The physical purpose is to establish the current direction during the intended switching interval, whose recirculation paths depend on that direction.[ref]
Let nominal sample times be and , and a nominal target time be . Actual sample times are and , and actual target time is , with absolute timing bounds . Measurements areAssume , and over all nominal and possible actual times and the intervals connecting them. Comparing each actual sample with its nominal-time value using the first-derivative bound, then applying the current-sign certificate with a curvature bound, givesThe triangle inequality proves this conservative enclosure without assuming independent or random timing errors. Its units are current: a timing error multiplied by a current-slew bound gives an amplitude error. A small curvature bound alone is insufficient, because a steep affine ramp has zero curvature but remains sensitive to relative timing.
For an original example, use , , and . The amplitude-plus-curvature allowance is . With and , timing addsThe full bound is . A prediction therefore certifies a positive target current of at least . To certify a whole switching interval, minimize over that interval rather than checking only one instant.
Shared-clock cancellation in current extrapolation can make the separate timing allowances conservative. If both samples and the target undergo exactly the same time translation, an affine ramp is still extrapolated exactly. The relevant error is relative timing; a common shift of the acquisition clock and a separately timed switching command need not cancel. Report which clocks, triggers and transport delays define the target.
A proposed check uses a known current ramp and an independently timed reference trace, deliberately perturbs sample and command timing, and tests whether the resulting errors stay inside the enclosure. Repeat near switching transitions. Slew and curvature assumptions must cover those transitions, not only the quiet portion used to fit a smooth waveform.