Abstract
The widespread exploitation of the millimetre-wave band for communications relies on the continual development of new technologies to realise affordable high-performance transceivers. Nowadays, the conventional superheterodyne transceiver architectures are starting to be replaced by direct conversion techniques, which can provide a more flexible and attractive engineering solution. The approach investigated in this thesis is to realise a transmitter by using Digital Signal Processing (DSP) to control a Monolithic Microwave Integrated Circuit (MMIC) vector modulator. A major part of this work is on software algorithms for generating the in-phase (I) and quadrature (Q) components at baseband for driving the vector modulator. Software has been developed to provide the functions of modulation, linearisation, and digital frequency shifting. Various measurement results are presented at 1.8GHz, 38GHz, and 60GHz using C/C++ and Matlab programming to implement digital generation of m-PSK and m-QAM modulated signals. The integration of RF and DSP functions is a multidisciplinary subject, with scope for many innovations, in addition to the main software work, two novel ways of realising a vector modulator have been demonstrated and an investigation has been made on Single Side-Band (SSB) Binary Phase Shift Keying (BPSK), which gives the same spectral efficiency in principle as QPSK without the complexity.