ACOUSTIC SIGNAL PROCESSING DEVICES (SURFACE WAVE TRANSDUCER STUDY)

摘要

The objective of the program has been to expand and refine the analysis and design of interdigital surface wave transducers. The report describes a new three-port circuit model analysis which, on the basis of comparison with experimental results, gives an excellent description of the operation at arbitrary harmonics of single and double electrode transducers with arbitrary metallization ratios and polarity sequences. Two other areas of investigation which are summarized in this report were described in detail in the previous Semi-Annual Report for this contract. The first is an experimental study establishing the crossed field Mason bulk wave model as giving an accurate description of acoustic reflections in transducers operating near acoustic synchronism. The model described in Section Two of this report extends these results to higher harmonic operation. The second additional area is a design procedure whereby nondispersive filters with any reasonably smooth pass band shape may be synthesized using nonperiodic transducers with practically no appodization. Three devices were successfully built using this procedure.