added capture time for every sweep

python_app/storage/npz/serialize.py

@@ -22,7 +22,14 @@ def _write_interleaved_complex(buffer: bytearray, values: np.ndarray) -> None:
 
 
 def serialize_trace_collection(collection: SweepCollection, magic: int) -> bytes:
-    """Serialize one raw/preprocessed trace collection into ring-compatible binary format."""
+    """Serialize one raw/preprocessed trace collection into ring-compatible binary format.
+
+    The trailer is appended after the trace blocks so older readers, which stop at
+    the last block, still decode the traces: first the collection capture window,
+    then a per-trace window table (one ``(start_ns, end_ns)`` pair per trace, in
+    trace order). See :func:`python_app.orchestration.shm.decoder.decode_trace_collection`
+    and ``read_trace_collection`` in ``common_cpp/ipc/src/shared_types.cpp``.
+    """
     buffer = bytearray()
     buffer.extend(struct.pack("<IQQI", magic, collection.collection_id, collection.monotonic_ns, len(collection.traces)))
 
@@ -48,6 +55,11 @@ def serialize_trace_collection(collection: SweepCollection, magic: int) -> bytes
             int(collection.capture_end_ns),
         )
     )
+    buffer.extend(struct.pack("<I", len(collection.traces)))
+    for trace in collection.traces:
+        buffer.extend(
+            struct.pack("<QQ", int(trace.capture_start_ns), int(trace.capture_end_ns))
+        )
     return bytes(buffer)
 
 

python_app/storage/npz/snapshot_numpy.py

@@ -124,6 +124,17 @@ def save_trace_history_binary(stage_dir: Path, history: list[SweepCollection], m
                     "capture_start_ns": int(collection.capture_start_ns),
                     "capture_end_ns": int(collection.capture_end_ns),
                     "trace_count": len(collection.traces),
+                    # Also in the .bin trailer; repeated here so per-combo timing is
+                    # readable without decoding the binary payload.
+                    "traces": [
+                        {
+                            "input": int(trace.combo.input),
+                            "output": int(trace.combo.output),
+                            "capture_start_ns": int(trace.capture_start_ns),
+                            "capture_end_ns": int(trace.capture_end_ns),
+                        }
+                        for trace in collection.traces
+                    ],
                 },
                 indent=2,
             ),
@@ -182,6 +193,10 @@ def save_trace_history_numpy(
                     "input": int(trace.combo.input),
                     "output": int(trace.combo.output),
                     "points": int(freq.size),
+                    # When each combo was measured, which in a switched matrix is
+                    # spread across the collection window rather than aligned with it.
+                    "capture_start_ns": int(trace.capture_start_ns),
+                    "capture_end_ns": int(trace.capture_end_ns),
                     "freq_file": f"{tag}_freq.npy",
                     "s11_file": f"{tag}_s11.npy",
                     "s21_file": f"{tag}_s21.npy",

python_app/storage/npz/store.py

@@ -117,6 +117,8 @@ class NpzStore(StoreApi):
                 {
                     "input": trace.combo.input,
                     "output": trace.combo.output,
+                    "capture_start_ns": int(trace.capture_start_ns),
+                    "capture_end_ns": int(trace.capture_end_ns),
                     "freq_key": freq_key,
                     "s11_key": s11_key,
                     "s21_key": s21_key,
@@ -177,6 +179,8 @@ class NpzStore(StoreApi):
                         frequency_hz=freq,
                         s11=s11,
                         s21=s21,
+                        capture_start_ns=int(combo.get("capture_start_ns", 0)),
+                        capture_end_ns=int(combo.get("capture_end_ns", 0)),
                     )
                 )
 

python_app/storage/npz/vna_history_json.py

@@ -25,6 +25,10 @@ class TraceRecord:
     stage_index: int
     frequency_hz: np.ndarray
     samples: np.ndarray
+    # End of this trace's own sweep, or 0 when the producer reported no per-trace
+    # timing. Preferred over the collection timestamp for the exported sweep time:
+    # in a switched matrix each combo is measured at a different instant.
+    capture_end_ns: int = 0
 
 
 def _normalize_channel(channel: str) -> str:
@@ -85,6 +89,7 @@ def _build_stage_records(
                 stage_index=int(stage_index),
                 frequency_hz=frequency_hz,
                 samples=samples,
+                capture_end_ns=int(trace.capture_end_ns),
             )
         )
     return records
@@ -137,7 +142,15 @@ def _build_sweep_history(
 
         start_freq_hz = float(base.frequency_hz[0])
         stop_freq_hz = float(base.frequency_hz[-1])
-        timestamp_sec = float(base.monotonic_ns) / 1_000_000_000.0 if base.monotonic_ns > 0 else float(fallback_index)
+        # Prefer the exported trace's own sweep time: with a switching matrix the
+        # combos of one collection are measured milliseconds apart, so the
+        # collection timestamp misplaces every combo but the last.
+        if base.capture_end_ns > 0:
+            timestamp_sec = float(base.capture_end_ns) / 1_000_000_000.0
+        elif base.monotonic_ns > 0:
+            timestamp_sec = float(base.monotonic_ns) / 1_000_000_000.0
+        else:
+            timestamp_sec = float(fallback_index)
 
         history.append(
             {