Digital Computer Simulation of Sampled-Data Communication Systems Using the Block Diagram Compiler: BLODIB

The study of complex communications systems by digital computer simulation is facilitated by use of the Block Diagram Compiler, BLODIB. 1 The source language accepted by the compiler is oriented towards communication system engineers and analysts who are already adept at handling block diagrams (or transfer functions) of complete systems. BLODIB is easily learned even by persons who have had little or no previous programming experience. The language of the compiler was designed specifically for simulating a wide variety of sampled-data 345 346 T H E BELL SYSTEM TECHNICAL JOURNAL, MARCH I960 system problems as well as simulating sampled-data approximations to continuous (analog) systems. The capabilities of BLODIB make possible the simulation of systems which were impossible for the old BLODI 2 compiler to handle. In particular, simulation of voice-communication and speech bandwidth compression systems such as vocoders, are accomplished more easily. The digital computer simulation of these systems was pioneered at Bell Telephone Laboratories using the original BLODI language. 3,4 While such systems were programmed in a few weeks time with a minimum of difficulty, it is now possible to program the same systems in about one day. I I . NEED FOR SIMULATION