Changes

csv_preprocessor.py

@@ -65,6 +65,10 @@ CLK_LP_LOW_MIN_NS = 300.0
 HS_BURST_AMPLITUDE_MIN_MV = 40.0  # mV — below this, no real HS burst is present
 #   Lowered from 50 mV: 48 mV capture (0001) was a false alarm; true flicker (0008) at 34 mV.
 
+HS_BURST_AMPLITUDE_HIGH_MV = 70.0  # mV — above this with short LP-low → anomalous LP states
+#   Normal HS (dynamic video) = ~15–40 mV P95-P5/2 on LP probe (RC-filtered).
+#   LP-01/LP-10 states in the burst window (cap 0042 type) produce 130+ mV → flag these.
+
 # Mode A minimum amplitude: LP-11-return edge artifacts produce near-zero amplitude in the
 # burst window (burst is pure LP-low DC between two LP-11 regions).  Require ≥ this to
 # distinguish a genuine weak-HS attempt from a false rolling-std trigger on LP-11 return.
@@ -752,6 +756,7 @@ class LPMetrics:
     # Flicker detection
     # A capture is flagged when the LP-low plateau is absent or shorter than
     # FLICKER_LP_LOW_MAX_NS.  Normal captures show ~340 ns; flicker shows 0–50 ns.
+    hs_rolling_std_found: bool = False  # rolling-std fired in HS window after LP-low ended
     flicker_suspect: bool = False
 
     warnings: list = field(default_factory=list)
@@ -891,6 +896,9 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
     n_hs_bursts      = 0
     hs_burst_dur_ns  = None
     hs_amplitude_mv  = None
+    hs_rolling_std_found = False
+    s_end = None
+    rstd  = None
 
     if len(lp11_regions) >= 1:
         # Measure LP-11 → HS exit gap (LP-01 + LP-00 combined) using a rolling
@@ -943,6 +951,17 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
                      float(np.percentile(burst_volts, 5))) / 2 * 1000, 1
                 )
 
+        # Did rolling-std fire in the actual HS window (after LP-low ended)?
+        # With dynamic display content (video), genuine HS keeps rolling-std above
+        # threshold; absent HS does not.  Used to gate Mode B/D false positives.
+        if lp_low_duration_ns is not None:
+            lp_low_end_idx = s_end + int((lp_low_duration_ns + 50.0) * 1e-9 / dt)
+            hs_check_end   = min(lp_low_end_idx + int(1000e-9 / dt), len(rstd))
+            if lp_low_end_idx < len(rstd):
+                hs_rolling_std_found = bool(
+                    np.any(rstd[lp_low_end_idx:hs_check_end] >= HS_OSC_STD_V)
+                )
+
     # ── Warnings ─────────────────────────────────────────────────────────
     warnings = []
     continuous_hs_clk = (not lp11_regions) and (channel == "clk") and (float(volts.max()) < LP11_HIGH_V)
@@ -1027,16 +1046,27 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
             # Mode A2: rolling-std never fired — HS absent or amplitude below HS_OSC_STD_V;
             # weak oscillations are misclassified as LP-low, masking the true HS failure
             or lp11_to_hs_ns is None
-            # Mode B: LP-low anomalously short + low amplitude = marginal HS launch
+            # Mode B: LP-low anomalously short + low amplitude = marginal HS launch.
-            or _lp_low_short
+            # Gated by hs_rolling_std_found: if HS actually launched (rolling-std fires
+            # after LP-low ends), LP-low being short is a timing anomaly but not a flicker.
+            or (_lp_low_short and not hs_rolling_std_found)
             # Mode D: LP-low normal, noise-spike lp11_to_hs (< 50 ns), low HS amplitude.
-            # Requires dynamic display content (video) during the test — with static/DC content
+            # Requires video/dynamic content. Gate: if rolling-std fires after LP-low ends,
-            # the probe noise floor is 15–35 mV regardless of HS health, making this unreliable.
+            # HS launched normally and the early lp11_to_hs was just the LP-low edge trigger.
             or (lp11_to_hs_ns is not None
                 and lp11_to_hs_ns < LP_LOW_DUR_MIN_NS
-                and not _lp_low_short)
+                and not _lp_low_short
+                and not hs_rolling_std_found)
         )
     )
+    # Mode E: short LP-low with anomalously HIGH amplitude — LP-01/LP-10 states in the
+    # burst window (link failed to launch HS cleanly).  Normal LP probe HS = 15–40 mV;
+    # LP-01/LP-10 DC levels produce 70+ mV.  Confirmed: cap 0042 (lp_low=61 ns, amp=133 mV).
+    hs_burst_anomalous = (
+        _lp_low_short
+        and hs_amplitude_mv is not None
+        and hs_amplitude_mv > HS_BURST_AMPLITUDE_HIGH_MV
+    )
     # Mode C: no LP-11 at all → link silent (but exclude CLK which is always HS)
     link_silent = (
         channel == "dat"
@@ -1056,6 +1086,7 @@ def analyze_lp_file(path: Path) -> "LPMetrics":
                     # positives when noise triggers gave lp_low < 50 ns with normal HS.
                     lp_low_duration_ns is None
                     or hs_burst_absent
+                    or hs_burst_anomalous
                 )
             )
         )