From The Free On-line Dictionary of Computing (19 January 2023):
Block Diagram Compiler
BDL
<simulation, language> (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)