Medical ultrasound pulse structure

Some aspects of the extremely complex structure of the pulses utilised in medical ultrasound pulse—echo imaging devicesare investigated. The following features are examined, in many instances from a fresh point of view: diffraction, Fourierrepresentation, directivity spectrum, propagation of pulse projections, causality, superluminality, and header wave compo-nent. Analytical results are underpinned by experimental findings with (single-element) wideband ultrasound transducers.The discussion is conducted within the context oflinear fields.Keywords: Ultrasound pulses; diffraction; directivity spectrum; causality; superluminality.