The spectrum and power efficiency offered by Single Sideband (SSB) modulation techniques has aroused considerable interest world-wide. At present, the British, American and Canadian regulatory bodies are considering the licensing of frequency bands, dedicated to SSB mobile radio equipment, both on an experimental and commercial basis. In this context, much of the work described in this thesis has been presented to the appropriate committees as evidence of the processing techniques available for facilitating the efficient use of SSB, for both speech and data communications, up to 1GHz operating frequencies. The thesis begins by analysing the mobile radio propagation characteristics in detail, demonstrating the need for suppression of the rapid fading of the received signal. A technique termed Feedforward Signal Regeneration (FFSR) is presented which fulfils this requirment simultaneously correcting for both the random amplitude and phase fluctuations. In connection with the FFSR system, a reference configuration called Transparent Tone-In-Band (TTIB) is introduced which allows the transmission of a 'transparent' reference centrally within the audio information band. This transparency of the reference facilitates the use of simple coherent data detection systems in the multipath fading environment. Finally, the incorporation of amplitude companding into SSB equipment is shown to add significantly to the channel improvement obtained with FFSR processing, giving rise to a mobile speech communications link at UHF of comparable fidelity to a conventional FM system.
|Date of Award||1983|