.. _auto_curve_disp_to_ad:

*DISP TO ACCELERATION-DISPLACEMENT*
===================================

Converts a displacement–time curve into an Acceleration-Displacement (A-D) diagram by differentiating twice and optionally filtering the result. Use this worker when building occupant-safety or crash-dynamics post-processing chains that require an A-D plot from raw displacement data.

When to use
-----------

Classification: **process**.

Tagged: ``AD_diagram``, ``CFC``, ``SAE``, ``acceleration_displacement``, ``crash``, ``curve_transform``, ``differentiation``, ``disp_to_ad``.

Inputs
------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20 20 20

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Base Curve
     - base_curve
     - vector
     - —
     - 
     - Input displacement–time curve (vector of [time, displacement] pairs); units should be consistent with x_sf and y_sf scale factors before processing.
   * - X Scale-factor
     - x_sf
     - scalar
     - 1
     - 
     - Scale factor applied to the X-axis (time) of the input curve before differentiation; default 1.0 (no scaling) — adjust when time data is not in seconds.
   * - Y Scale-factor
     - y_sf
     - scalar
     - 1
     - 
     - Scale factor applied to the Y-axis (displacement) of the input curve before differentiation; default 1.0 (no scaling) — adjust when displacement data is not in metres or mm.
   * - FilterType
     - filter_type
     - scalar
     - lsprepost_sae
     - 
     - Low-pass filter algorithm applied after differentiation; choose from lsprepost_sae (default), lsprepost_bw, lsprepost_cos, lsprepost_fir, cfc, or sae — leave default for standard LS-PrePost-compatible SAE filtering.
   * - Frequency
     - frequency
     - integer
     - 300
     - 
     - Filter cut-off frequency in Hz (options: 30, 60, 120, 180, 300, 600, 1000); default 300 Hz — select lower values (e.g. 60 or 180) for heavily noisy signals or when matching a specific regulatory channel class.

Outputs
-------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20

   * - Label
     - ID
     - Type
     - Description
   * - curve_disp_to_ad_output_1
     - curve_disp_to_ad_output_1
     - vector
     - Resulting Acceleration-Displacement curve (vector of [displacement, acceleration] pairs) after double differentiation and optional filtering of the input displacement–time signal.

Disciplines
-----------

- data.curve.transform
- data.signal_processing
- engineering.crash.dynamics
- engineering.crash.occupant_safety

Runnable example
----------------

A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: `/api/workflow/example?id=curve_disp_to_ad <https://www.d3view.com/api/workflow/example?id=curve_disp_to_ad>`_

.. raw:: html

   <hr style="margin-top:2em">
   <p style="font-size:11px;color:#888">
   Auto-generated from <code>transformation</code> schema. Worker id: <code>curve_disp_to_ad</code>. Schema hash: <code>1dae86527c6a</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>