Ultrasonic imaging system using plural square wave pulse trains of successively delayed intervals

摘要

A sector scan ultrasonic imaging system comprises a source of a plurality of square wave pulse trains each being delayed by a unit quantization time with respect to adjacent trains, and a plurality of transmitter circuits corresponding to the elements of a transducer array. The duration of each square wave pulse is an integral multiple of the unit quantization time interval. Each transmitter circuit includes a read only memory in which a set of different digital delay time data is stored for the corresponding transducer element and is arranged to be retrieved in response to each angle increment of the ultrasonic beam transmitted from the array. Further included are a data selector for selecting a pulse train in response to a pulse train selection data retrieved from the memory and a programmable counter for counting the pulses of the selected train to generate an output in accordance with a pulse selection data retrieved from the memory. An Exclusive-OR gate is further included to provide bit inversion of the selected pulse train in selective response to the binary state of a data retrieved from the memory so that the number of available square wave pulse trains is doubled. A gating circuit responds to the output of the counter by gating a pulse of the selected pulse train to the corresponding transducer element.