| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 98 === Software defined radio (SDR) is attractive for future approach in implementation of modulation techniques because of reconfigurable and multimode operation capabilities. Thus, modulation techniques based SDR is a promising approach in developing emerging wireless technologies such as 3G and 4G wireless communications. In this thesis, we design a SDR to investigate modulation techniques in both analog and digital method. Then, we focus on phase shift keying (PSK) modulation and quadrature amplitude modulation (QAM) since they are widely used in both military and commercial communication systems. Modulation techniques present themselves with specific applications according to reasonable bit error rate (BER) and other parameters when compared to other modulation techniques. Therefore, it is necessary to evaluate the performance of communication systems by analyzing BER. We first consider BER of different kinds of digital modulation techniques in theory and analyzed them by using Matlab. Next, the experimental study is performed on a test platform for a practical proof of the theory. The test platform is based on the Ettus Universal Software Radio Peripheral (USRP) hardware. Several tests are carried out to observe signals and analyze an efficiency of communication system. The results confirm that the programmed SDR can demodulate the various kinds of audio signal and also closely match the theoretical analysis.
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