The Free On-line Dictionary of Computing (30 December 2018):

Block Diagram Compiler
BDL

    (BDL) A block diagram simulation tool,
   with associated language.

   ["A Software Environment for Digital Signal-Processing
   Simulations," D.H. Johnson & R.E. Vaughan, Circuits Systems
   and Signal Processing 6(1):31-43, 1987].

   (2000-07-17)