FPGA implementation of reconfigurable frequency demodulators

Modulators and Demodulators are considered as the most important blocks for communication, wireless and mobile systems. Modulators are used on the transmitter side of any system and demodulators are used on the receiver side of corresponding system. Frequency modulators are the most commonly used modulators due to their numerous advantages over other modulators which include better fidelity and noise immunity. Frequency demodulators are used to extract the original information-bearing signal from a modulated carrier wave. Different types of frequency demodulators exist with each technique possessing its own advantages and disadvantages which enables the usage of different types of frequency demodulation technique for different applications. This motivated the design of reconfigurable frequency demodulators wherein the type of demodulator can be selected on-the-fly which has a wide potential application for communication systems, mobile communication, wireless communication, software defined radio and many more. The four different types of demodulation techniques used for reconfiguration in the proposed work are Fast Fourier Transform based demodulator, Reusable Goertzel block based demodulator, Phase locked loop based demodulator and Quadrature detector. The proposed reconfigurable frequency demodulator system is implemented on a Virtex-5 FPGA based evaluation board and the results are reported in the paper. It is observed that 56.03% of hardware resources and 71.36% of power is saved on using proposed reconfigurable architecture over non-reconfigurable architecture. The proposed reconfigurable architecture can be used for various other systems and applications too.