.. index:: mode-stirred chamber, MSC calibration, autocorrelation

MSC calibration and autocorrelation data
========================================

MSC uses separate containers for main calibration, EUT calibration, and
autocorrelation. Every dataset is addressed by ``description``.

Shared raw-data structure
-------------------------

Field and reference-antenna data for main and EUT calibration are stored at::

   raw["efield"][frequency][tuner_position][probe_position][sample]
   raw["pref"][frequency][tuner_position][antenna_position][sample]

``frequency`` is numeric in Hz. ``tuner_position`` is normally a string in
existing histories; position keys are integers. Every entry has ``value``,
``pfwd``, and ``pbwd``. For ``efield``, ``value`` is a vector of three
field-strength quantities; for ``pref`` it is a power quantity. ``pfwd`` and
``pbwd`` are forward and reverse power.

``rawData_MainCal[description]`` and ``rawData_EUTCal[description]`` also
contain ``noise``, ``etaTx``, ``etaRx``, and ``mg``. ``noise`` holds the noise
measurement, ``etaTx`` and ``etaRx`` the frequency-dependent antenna
efficiencies. ``mg`` is the persisted graph description, not an open device
connection.

Main calibration
----------------

``Evaluate_MainCal`` creates ``processedData_MainCal[description]``. All
non-scalar keys are fundamentally indexed by ``frequency``:

* ``PMaxRec`` and ``PAveRec``: maximum and average received power by reference
  antenna position;
* ``PInputForEField`` and ``PInputForRecAnt``: average input power;
* ``PInputVarationForEField`` and ``PInputVarationForRecAnt``: maximum/minimum
  input-power ratio (the historical spelling ``Varation`` is contractual);
* ``EMax``: maximum x/y/z component by probe position; ``EMaxT``: maximum
  field magnitude;
* ``ACF``: average chamber calibration factor; ``IL``: average insertion loss;
* ``Enorm``, ``EnormT``, ``EnormAveXYZ``, ``EnormAve``, and ``EnormTAve``:
  fields normalized by ``sqrt(PInput)`` and their averages;
* ``SigmaXYZ``, ``Sigma24``, ``SigmaXYZ_dB``, and ``Sigma24_dB``: spread
  quantities.

``EnormTmax2`` remains as a historical, currently unpopulated frequency
container. ``Standard_Used`` names the selected evaluation standard.
``CalculateLoading_MainCal`` creates an additional ``"empty,loaded"`` dataset
with ``Loading[frequency]``.

EUT calibration
---------------

``Evaluate_EUTCal`` creates ``processedData_EUTCal[description]`` and within
it similarly creates ``PMaxRec``, ``PAveRec``, the four
``PInput*`` tables, ``EMax``, ``Enorm*``, and ``Sigma*``. It also adds:

``CCF`` and ``CCF_from_PMaxRec``
   Chamber calibration factors from average and maximum received power.

``CLF`` and ``CLF_from_PMaxRec``
   Chamber loading factors derived relative to the selected main calibration.

If field-probe values are absent, field-related tables are ``None`` at that
frequency while reference-antenna evaluation can still be available.
``CalculateLoading_EUTCal`` additionally creates ``"empty,EUT"`` with
``Loading[frequency]``.

Autocorrelation
---------------

``rawData_AutoCorr[description]`` contains ``efield``, ``tpos``, and ``mg``.
The field path follows the shared structure; ``tpos`` is the ordered list of
tuner positions actually measured.

Depending on the ``skip`` selection, ``Evaluate_AutoCorr`` writes to
``processedData_AutoCorr[description]``:

* ``TunerPositions``: sorted tuner positions;
* ``DistributuionOfr``: ``n``, ``r``, ``pdf``, ``cdf``, ``rho``, and ``rho0``;
  the historical spelling is contractual;
* ``AutoCorrelation[frequency][probe_position][component]``: cyclic
  autocorrelation coefficient sequence;
* ``NIndependentBoundaries`` with the same index: estimated independent tuner
  positions;
* ``Statistic[frequency][probe_position][component]``: samples, histogram,
  empirical and fitted distributions, and chi-square and KS p-values.
  ``independent_subset_used`` and ``selected_sample_count`` show whether an
  independent subset was used.

These statistical results depend on ``alpha``, ``rho``, ``rho0``, ``lag``,
``every``, and ``offset`` passed to evaluation. They are currently not
persisted as a dedicated metadata block and must be recorded separately for a
reproducible external reevaluation.

With explicit RC routing, raw sample bundles may additionally contain the
optional ``rx_capture`` field. Its schema, units and the 40 dB switching rule
are documented in :doc:`msc-immunity-emission-data`. This applies to main
calibration, EUT calibration and autocorrelation; old bundles remain readable
without this field.