| Summary: | Surface Acoustic Wave (SAW)-controlled oscillators possess many features which make them attractive as frequency sources in communications applications. This thesis deals with SAW oscillators, both resonator and delay stabilised, and their incorporation in communications synthesisers modules intended primarily for mobile radio applications. A review of SAW technology and the theory and design of SAW controlled oscillators together with related topics on frequency synthesis techniques is included. A SAW resonator-based personal radio-telephone module is described. This module demonstrates improved performance over existing commercial equipment. VHF and UHF multi-channel digital frequency synthesisers in which SAW delay line oscillators were successfully employed as frequency sources are also presented. Finally, a SAW based UHF Gemini synthesiser is demonstrated. This module is capable of fast switching, a feature of particular interest in frequency-hopped communications. All these modules are designed using the indirect frequency synthesis approach, in which the medium and long term stabilities of the SAW oscillators are controlled by a highly stable crystal reference.
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