Apparatus for ultrasonic scanning

Claim 1

Ultrasonic scanning apparatus including electronic delay circuitry for delaying echo signals produced in use by a multiplicity of transducers of the apparatus such that the phase relationship between respective echo signals is substantially maintained for each of a succession of ultrasonic scanning lines, the circuitry comprising a multiplicity of partial-line digital stores, each partial-line digital store being adapted for storing data in digital form corresponding to a part of an ultrasonic scanning line, a group of partial-line digital stores being associated with each of the transducers such that the total number of partial-line digital stores available for association with each transducer has a total storage capacity substantially less than that required for storing the data from the transducer which is to be stored during the generation of an ultrasonic scanning line, each group comprising at least three partial-line digital stores and being operated such that readout of part of the data of one ultrasonic scanning line makes room for the storage of a further part of the data of the same ultrasonic scanning line, and control means arranged such that, in use, data corresponding to echo signals is sequentially written in to the partial-line digital stores of the group for each of the transducers, beginning with the first such transducer to receive an echo signal, until at least the first partial-line digital store of the group for the last such transducer to receive an echo signal has been supplied with data, said control means being operative for simultaneously reading out stored data from all of the groups of partial-line digital stores after the time when the group of partial-line digital stores for the last such transducer to receive an echo signal has been supplied with data and before the group of partial-line digital stores associated with the first such transducer to receive an echo signal has exceeded its storage capacity.