The paper adopts VHDL in the Max-plus II programming environment based on the characteristics of the HDB3 in digital baseband transmission systems and CPLD/FPGA,which has made the HDB3 encoder and the decoder.

• 针对数字基带传输系统中HDB3信号的特点；采用基于CPLD/FPGA的VHDL语言；在Max+plusII的环境中；实现HDB3数字基带信号的调制、解调器.