Acoustics of hand portable mobile radios.
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
The aim of the project was to investigate the acoustics of hand portable radios identifying key parameters contributing to their performance and from these findings develop a design guide. A systems engineering approach was taken with the project focus on internal and external acoustic and vibration interactions. The internal interactions investigated were between electrical and mechanical systems while the external interactions included the influence of the user and environment on the radio performance. The interactions provided quantitative verification of the Orca's perceived poor audio performance and enabled a design guide to be developed to prevent the issues from recurring. A significant proportion of the work was experimentally based and provides methodology to aid future analysis of other products. Commercially available software, LMS SYSNOISE, was utilised to implement a vibro-acoustic finite and boundary element model of the radio. The results were verified against experimental measurements. It was found that SYSNOISE was suitable as a design tool for predicting modes and trends but was unsuccessful at predicting the magnitude of acoustic radiation. The reason for this was attributed to difficulties in modelling damping. The design guide contains a design procedure and recommendations for acoustic information management. To realise the full benefit of acoustic analysis procedures need to be implemented to incorporate the information into mechanical design, electrical design and also sales and marketing.