In this paper the authors present a theoretical background overview of the digital communication systems and the BPSK modulation and demodulation. The purposed design is the BPSK system. The BPSK modulation and demodulation represents an important modulation technique in terms of signal power. The BPSK system is simulated using matlab/simulink environment and system generator, a tool from Xilinx used for FPGA design as well as implemented on two spartan 3E starter kit boards. The first board behaves as a modulator and the second as a demodulator.