VHDL Implementation of π/4 QPSK MODEM

Π/4 QPSK technique is one of the most popular Phase shift keying technique used widely in wireless communication systems like satellite radio. Using analog circuits to implement the modulator and demodulator is not suitable for some applications like biomedical signal transmission. Analog circuits have large size and high power consumption. So for such application we have to go for digital methods of implementation. The main advantages of the digital design are frequency agility, repeatability, cost and the simpler reconfiguration compared to analog. Very high speed integrated circuits hardware description language (VHDL) enables us to model a digital system. This system then can be physically implemented on hardware using field programmable gate arrays (FPGA), which is a highly configurable silicon engine. In this paper π /4 QPSK modulator and demodulator (MODEM) is designed in VHDL and its expected simulation is carried on Xilinx ISE 8.2i environment.