Influence of component errors on the directivity function of pulsed, ultrasonographic linear arrays

The directivity of linear arrays can deteriorate by reason of component errors such as variations in the sensitivity of the array elements, and variations in the electronic delays applied to synthetic aperture focusing. A prototype 16 channel linear array system has been analysed by calculating the directivity functions corresponding to random-error ensembles in relation to sensitivity and delay. With state-of-the-art components, the main lobe of the directivity function is hardly influenced, but the tails of the function show stronger variation, and also become asymmetrical.