In terrestrial television transmission multiple paths of various lengths can occur between the transmitter and the receiver. Such paths occur because of reflections from objects outside the direct transmission path. The multipath signals arriving at the receiver are all detected along with the intended signal causing time displaced replicas called 'ghosts' to appear on the television picture. With an increasing number of people living within built up areas, ghosting is becoming commonplace and therefore deghosting is becoming increasingly important. This thesis uses a deterministic time domain approach to deghosting, resulting in a simple solution to the problem of removing ghosts. A new video detector is presented which reduces the synchronous detector local oscillator phase error, caused by any practical size of ghost, to a lower level than has ever previously been achieved. From the new detector, dispersion of the video signal is minimised and a known closed-form time domain description of the individual ghost components within the detected video is subsequently obtained. Developed from mathematical descriptions of the detected video, a new specific deghoster filter structure is presented which is capable of removing both inphase (I) and also the phase quadrature (Q) induced ghost signals derived from the VSB operation. The new deghoster filter requires much less hardware than any previous deghoster which is capable of removing both I and Q ghost components. A new channel identification algorithm was also required and written which is based upon simple correlation techniques to find the delay and complex amplitude characteristics of individual ghosts. The result of the channel identification is then passed to the new I and Q deghoster filter for ghost cancellation. Generated from the research work performed for this thesis, five papers have been published.

This thesis presents a solution to the problem of receiving a signal in the shadow and fringe areas. Theoretical and experimental investigation of the field behind an obstacle in a line of sight transmission path for UHF / microwave signals has resulted in a new approach to the analysis of electromagnetic fields in the shadow of an obstacle. Analysis using this approach showed the field to consist of varying amplitude and phase distribution. Additional analysis predicted an increase in received signal could be achieved if correlation between the field and antenna structure could be obtained. This was accomplished with a new antenna design. The thesis presents experimental and photographic evidence to support the theory. A novel technique involving the matching of the antenna structure to the field distribution, resulted in an increase of received signal in the diffracted field of up to 4 dB.