Design and Implementation of Baseband Digital Modulator for CDMA Communication System

Code Division Multiple Access (CDMA) technique provides anti jamming capability, carrier frequency reuse and most importantly, avoids unauthorized access to the systems. aft. The paper presents the design and implementation of base band digital modulator for a CDMA communication system. It describes the selection criteria for spreading code along with their implementation. To achieve more hardware efficiency and good phase resolution, Coordinate Rotation Digital Computer (CORDIC) is used in realizing the base band BPSK modulator. The paper also presents the comparison of CORDIC based and look up table based modulator. The application of developed system in satellite communication is explored. The system is implemented on XILINX FPGA platform and tested in real time for its performance.