An experimental baseband data transmission system is implemented on the basis of 8-bit microprocessors. The system consists of three independent modules of encoder, pulse shaper and decoder. In order to explore all the advantages provided by the microprocessor-based hardware, each module is programmed on PROM``s wherever possible. The flexibility due to the programmed-logic enables both separate and combined experiments on the different types of line codes, pulse shapers, detection or decoding schemes, as well as the effects of channel distortions and noise. A variety of minimum bandwidth line codes are programmed on the basic corehardware, and some of the typical channel distortions encountered in practice are considered. The system performance is experimentally measured in such aspects as power spectram, eye pattern, and error probability, which then are compared with the theoretical values.