Characterisation of high frequency focused ultrasonic transducers using modulation transfer function: concept and experimental approach

The concept of the modulation transfer function, which is used to evaluate high quality optical systems, components and materials, has been adapted for the first time in a systematic way in ultrasonics to characterise high frequency focused transducers. The additional complexity of ultrasonics compared with optics has been analysed and treated. A 2-D MTF characteriser is presented, as a counterpart to the 1-D function in optics. An example of a complete experimental procedure providing the full performance of focused transducer is presented.