Design and evaluation of FPGA based frequency demodulators

Communication systems are extensively used in a large number of applications such as radar, aerospace, naval/maritime communication, mobile communication and many more. The most important module in designing communication system includes design of modulators and demodulators. Frequency modulation (FM) is widely used for various applications ranging from radio communication to on-board systems for aerospace and spacecraft applications. FM demodulators are used to demodulate the FM signals transmitted from such systems. In this paper, a novel attempt is made to use Goertzel algorithm for FM demodulation and its performance is compared with the system designed using Fast Fourier Transform (FFT). Also a reusable Goertzel block based FM demodulator is proposed which reduces the hardware resources on increasing the number of frequencies to be detected. All the above mentioned systems are implemented on a Xilinx Virtex-5 board and their results are reported. 60-82% of hardware resources are saved on using proposed reusable Goertzel block based demodulator, which inturn saved the power consumption of the proposed design.