nx_dynaoracle_gate.nx

nx_dynaoracle_gate.nx -- GATE for the shared ringdown estimator and the video oracle's derived constants. WHY THE FIXTURE IS AN ANALYTIC OSCILLATOR AND NOT A VIDEO CLIP. A gate whose fixture is a real clip can only assert that today's answer equals yesterday's answer -- it has no ground truth, so it detects drift and CANNOT detect being wrong. Here the fixture is a mass-spring-damper the gate integrates itself, so the TRUE natural frequency and damping ratio are known in closed form from k and c: w0 = sqrt(k/m), zeta = c/(2*sqrt(k*m)), wd = w0*sqrt(1-zeta^2). The teeth then ask whether rd_analyze RECOVERS numbers it was never told. That is an oracle, not a snapshot. EVERY TOLERANCE HERE IS DERIVED, NOT PICKED: * FREQUENCY: rd_analyze times a period by counting whole SAMPLES between zero crossings, so a plus-or-minus-one-sample error bounds the relative frequency error at 1/P where P is the period in samples. The tooth computes that bound from the fixture's own period. * DAMPING: rd_zeta_permil goes through rd_log2_q16, whose own header declares a worst error of about 0.086 in log2 inside an octave. That propagates as ln-error 0.086*ln2 = 0.0596, and for a lightly damped decay zeta is about delta/(2*pi), giving a bound near 9.5 permil. The tooth computes that from the declared constant instead of hard-coding the answer. A tolerance chosen after seeing the result is the defect this estate refuses; a tolerance derived from a declared imprecision is a contract. license_tier: ORIGINAL