added capture time for every sweep

data_acq_and_processing/common_cpp/ipc/include/shared_types.hpp

@@ -38,6 +38,13 @@ struct SweepTraceBlock {
     std::vector<Complex32> s11{};
     // Complex S21 samples for matching frequency points.
     std::vector<Complex32> s21{};
+    // Monotonic window in which THIS trace's sweep was measured, excluding the
+    // switch drive and settling that preceded it. In a switched matrix the
+    // collection is assembled combo by combo over many milliseconds, so the
+    // collection-level window says nothing about when an individual combo was
+    // measured. Zero on both is a valid "unmeasured" sentinel.
+    std::uint64_t capture_start_ns = 0;
+    std::uint64_t capture_end_ns = 0;
 };
 
 struct RawSweepCollection {

data_acq_and_processing/common_cpp/ipc/src/shared_types.cpp

@@ -172,6 +172,10 @@ void require_count_fits(std::uint32_t count, std::size_t min_bytes_each, BinaryR
     return trace;
 }
 
+// The capture windows live in a TRAILER after the trace blocks rather than inside
+// them, so a reader built before they existed still decodes every trace and simply
+// stops early. The trailer grows the same way: collection window first, then the
+// per-trace window table (one pair per trace, in trace order).
 void write_trace_collection(BinaryWriter& writer, std::uint32_t magic, const RawSweepCollection& collection) {
     writer.write(magic);
     writer.write(collection.collection_id);
@@ -184,6 +188,12 @@ void write_trace_collection(BinaryWriter& writer, std::uint32_t magic, const Raw
 
     writer.write(collection.capture_start_ns);
     writer.write(collection.capture_end_ns);
+
+    writer.write(checked_count_to_u32(collection.traces.size(), "Trace capture window count"));
+    for (const auto& trace : collection.traces) {
+        writer.write(trace.capture_start_ns);
+        writer.write(trace.capture_end_ns);
+    }
 }
 
 [[nodiscard]] auto read_trace_collection(BinaryReader& reader, std::uint32_t expected_magic) -> RawSweepCollection {
@@ -204,16 +214,31 @@ void write_trace_collection(BinaryWriter& writer, std::uint32_t magic, const Raw
         collection.traces.push_back(read_trace_block(reader));
     }
 
+    // Each trailer stage is optional: a payload from an older producer stops after
+    // the trace blocks (or after the collection window) and leaves the rest zeroed.
     if (reader.remaining_bytes() == 0U) {
         return collection;
     }
-    if (reader.remaining_bytes() != (sizeof(std::uint64_t) * 2U)) {
-        throw std::runtime_error("Unexpected trailing bytes in trace collection");
+    if (reader.remaining_bytes() < (sizeof(std::uint64_t) * 2U)) {
+        throw std::runtime_error("Truncated capture window in trace collection");
     }
 
     collection.capture_start_ns = reader.read<std::uint64_t>();
     collection.capture_end_ns = reader.read<std::uint64_t>();
 
+    if (reader.remaining_bytes() == 0U) {
+        return collection;
+    }
+
+    const auto trace_time_count = reader.read<std::uint32_t>();
+    if (trace_time_count != collection.traces.size()) {
+        throw std::runtime_error("Per-trace capture window count does not match trace count");
+    }
+    for (auto& trace : collection.traces) {
+        trace.capture_start_ns = reader.read<std::uint64_t>();
+        trace.capture_end_ns = reader.read<std::uint64_t>();
+    }
+
     return collection;
 }
 

data_acq_and_processing/preprocessing/calibration_master/src/calibration_master.cpp

@@ -34,6 +34,9 @@ auto CalibrationMaster::apply_to_trace(const ipc::SweepTraceBlock& measured_trac
     output.frequency_hz = measured_trace.frequency_hz;
     output.s21 = apply_s21(measured_trace.combo, measured_trace.frequency_hz, measured_trace.s21);
     output.s11 = apply_s11(measured_trace.combo, measured_trace.frequency_hz, measured_trace.s11);
+    // Calibration reshapes the samples, not when they were measured.
+    output.capture_start_ns = measured_trace.capture_start_ns;
+    output.capture_end_ns = measured_trace.capture_end_ns;
     return output;
 }
 

data_acq_and_processing/preprocessing/reference_master/src/reference_master.cpp

@@ -132,6 +132,9 @@ auto ReferenceMaster::apply_to_trace(const ipc::SweepTraceBlock& calibrated_trac
     output.frequency_hz = calibrated_trace.frequency_hz;
     output.s21 = apply_s21(calibrated_trace.combo, calibrated_trace.frequency_hz, calibrated_trace.s21);
     output.s11 = apply_s11(calibrated_trace.combo, calibrated_trace.frequency_hz, calibrated_trace.s11);
+    // Reference subtraction reshapes the samples, not when they were measured.
+    output.capture_start_ns = calibrated_trace.capture_start_ns;
+    output.capture_end_ns = calibrated_trace.capture_end_ns;
     return output;
 }
 

data_acq_and_processing/sweep_orchestrator/src/sweep_orchestrator.cpp

@@ -147,14 +147,18 @@ class DriverLifecycleGuard {
 // Worst-case serialized size of a collection given the configured combo count and sweep
 // point count, using the trace wire format (see ipc::write_trace_collection/write_trace_block):
 //   collection header: magic(4) + collection_id(8) + monotonic_ns(8) + trace_count(4)
-//                     + capture_start_ns(8) + capture_end_ns(8) = 40 bytes
+//                     + capture_start_ns(8) + capture_end_ns(8)
+//                     + trace capture window count(4) = 44 bytes
 //   per trace block:   input_pos(4) + output_pos(4) + point_count(4) = 12 bytes
 //                     + per point: frequency(4) + s11(8) + s21(8) = 20 bytes
+//                     + trailer: capture_start_ns(8) + capture_end_ns(8) = 16 bytes
 [[nodiscard]] auto worst_case_serialized_bytes(std::size_t combo_count, std::uint32_t sweep_points) -> std::size_t {
-    constexpr std::size_t kCollectionHeaderBytes = 40U;
+    constexpr std::size_t kCollectionHeaderBytes = 44U;
     constexpr std::size_t kTraceHeaderBytes = 12U;
     constexpr std::size_t kBytesPerPoint = 20U;
-    const std::size_t per_trace = kTraceHeaderBytes + (static_cast<std::size_t>(sweep_points) * kBytesPerPoint);
+    constexpr std::size_t kTraceTrailerBytes = 16U;
+    const std::size_t per_trace =
+        kTraceHeaderBytes + (static_cast<std::size_t>(sweep_points) * kBytesPerPoint) + kTraceTrailerBytes;
     return kCollectionHeaderBytes + (combo_count * per_trace);
 }
 
@@ -290,7 +294,12 @@ auto SweepOrchestrator::acquire_one_collection(
         // Production drivers ignore this; mock drivers use it to give every
         // (input, output) pair its own synthetic response.
         radar_driver_.set_active_combo(combo);
+        // Stamp around the sweep only: the switch drive and settling above belong to
+        // neither the previous combo nor this one, so excluding them keeps the window
+        // an honest "when was this combo actually measured".
+        const auto sweep_start_ns = ipc::current_monotonic_ns();
         auto sweep = radar_driver_.acquire_sweep();
+        const auto sweep_end_ns = ipc::current_monotonic_ns();
         validate_sweep(sweep);
 
         ipc::SweepTraceBlock trace{};
@@ -298,6 +307,8 @@ auto SweepOrchestrator::acquire_one_collection(
         trace.frequency_hz = std::move(sweep.frequency_hz);
         trace.s11 = std::move(sweep.s11);
         trace.s21 = std::move(sweep.s21);
+        trace.capture_start_ns = sweep_start_ns;
+        trace.capture_end_ns = sweep_end_ns;
         collection.traces.push_back(std::move(trace));
     }