Browsing by Author "Otolorin, Joel,Adeniyi"

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    Development of an Algorithm for Implementing a Low Cost Frequency Modulated(FM) Receiver
    (Obafemi Awolowo University, 2013) Otolorin, Joel,Adeniyi
    The study designed a suitable FM demodulation technique for use in software-defined radio receivers. It also developed an algorithm for implementing the software-defined FM receiver, and evaluated the performance of the algorithm for signal recovery at various sampling rate below the conventional Nyquist rate. This was with a view to developing a system that is characterized with a reduced sampling rate, toward enhancing the implementation of a low cost FM Receiver. An FM demodulation technique was selected with a view to designing a suitable algorithm, which is consistent with the better recovery of the message in FM and AM signals. The algorithm was implemented such that an amplitude-limited FM signal was sampled using ideal sampling technique, differentiated using Euler’s method, and detected using market paradigm. Under varying sampling rates, the performance of the algorithm was simulated in a MATLAB environment, and the spurious free dynamic ranges (SFDR) of the recovered waveform were obtained. The simulated results showed that the algorithm was able to recover the message signal when sampling was carried out at 0.4fc (carrier frequency), 0.5fc, fc, and 2fc for the AM demodulation algorithm, and at 0.4fc, 0.5fc, and 2fc for the FM demodulation algorithm. It was also observed that the optimum recovery of the message signal was achieved when under-sampled at 0.4fc at an SFDR value of 20dB for FM demodulation and 18dB for AM demodulation. These results also confirmed the better noise insensitive nature of FM signals over AM signals. This study concluded that the developed demodulation algorithm is suitable for recovering both FM and AM signals at minimal interoperability costs and for implementing software-based radio receivers.