Generates a test signal
Set to Zero: Silence is created
Set to One: Rectangle / Dirac is generated (contains all frequencies of the same amplitude and phase)
… at sample / length: determination of the delay / position of the Dirac and length (usually 1 sample)
Slope: Creates a test tone of any frequency
A neutral filter of ideal behavior can be created.
With this as a reference, subtractions or combinations of any variety can be generated.