AmplifierTest Virtual Workflow
==============================

The ``amplifier-test.py`` script can be run with virtual device
configurations for development and regression testing without laboratory
hardware. The standard virtual configuration models an amplifier installed in
the measurement rack with forward and backward power monitoring.

From the ``script`` directory, start the virtual amplifier test with:

.. code-block:: console

   python amplifier-test.py conf/amplifier-test-virtual/conf.py

An isolated amplifier with a power meter connected directly to the amplifier
output is modeled by the direct configuration:

.. code-block:: console

   python amplifier-test.py conf/amplifier-test-direct-virtual/conf.py

This configuration sets ``measurement_setup = "direct"``. Its names mapping
uses ``pm_out`` for the direct output power meter instead of the rack setup
keys ``pm_fwd``, ``pm_bwd`` and ``output``.

The direct configuration defines output cable and attenuator corrections as
passive graph nodes and references them on the DOT edges with the usual
``dev`` and ``what`` attributes. The virtual direct workflow uses two edge
corrections between ``amp_out`` and ``pm_out`` and includes a 40 dB output
attenuator.

For the direct setup, ``AmplifierTest`` also checks an optional power-meter
safety channel named ``MAXIN`` before it sets a signal-generator level. The
check estimates the power-meter input from the requested signal-generator
level and the graph correction from ``sg`` to ``pm_out``. The virtual direct
configuration and the R&S NRP Z21 configuration provide such a ``MAXIN``
channel. If the selected power-meter configuration does not provide it, this
additional power-meter protection is not available.

The same configuration can be run through the Qt UI with:

.. code-block:: console

   python amplifier-test-qt.py conf/amplifier-test-virtual/conf.py

The configurations use virtual signal-generator, amplifier and power-meter
drivers plus 0 dB virtual path corrections. Output files are written below the
respective configuration ``output`` directory.

The virtual configuration disables compression evaluation with
``do_evaluation = False``. The virtual power-meter data is deterministic and
useful for exercising the measurement, logging and pickle workflow, but it is
not a realistic compression characteristic.

The real Direct configuration under ``conf/amplifier-test-direct`` uses the
R&S SMF100A, the BLMA amplifier configuration and an R&S NRP Z21 power-meter
configuration as its initial hardware-oriented skeleton. Its direct cable and
attenuator correction nodes currently use local 0 dB placeholder path data and
must be replaced by the measured correction data for a real measurement. This
is also required for the ``MAXIN`` estimate to describe the actual
power-meter input.

The script writes:

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

   * - File
     - Purpose
   * - ``amplifier-test-virtual.p``
     - Final ``AmplifierTest`` pickle containing the measured history.
   * - ``amplifier-test-virtual-after-measure-<description>.p``
     - Intermediate pickle written after the measurement step.
   * - ``amplifier-test-virtual.log``
     - Text log from the measurement run.

The hardware-independent path is covered by
``test_amplifier_test_script.py``. Run the focused test from the repository
root with:

.. code-block:: console

   PYTHONPATH=src:../scuq/src python -m pytest test/test_amplifier_test_script.py