Implementation of DQPSK and OWM-QAM as software defined radio system.

摘要

This thesis studies a software-defined radio (SDR) architecture. Base on which two independent systems, DQPSK and orthogonal waveform modulated quadrature amplitude modulation (QAM) (OWM-QAM), are implemented in one programmable platform. The purpose is to explore the capabilities of a general purpose hardware (field-programmable gate-array (FPGA)) to realize several different modulation techniques and extend the flexibility of system implementation.;In the DQPSK system, this thesis introduces a non data-aided (NDA) method to estimate and compensate for the residual timing errors, which lead to sampling errors at the receiver.;This thesis also addresses the implementation of a OWM-QAM system. This method uses orthogonal waveforms to modulate the IQ channels. One of the orthogonal channels is used for clock and carrier recovery. Since QAM modulation is sensitive to the magnitude attenuation, which is inevitable via wireless channels, this thesis introduces an easy but effective way to estimate and compensate for the amplitude scaling.