Ultrasonic imaging apparatus using digital control

Claim 1

An ultrasonic imaging apparatus comprising: transducer means having a plurality of transducer elements for transmitting ultrasonic pulses along a beam to an object and receiving ultrasonic echoes from the object to produce echo signals; transmitter means for exciting said elements at different delayed timings to steer or focus said beam, said transmitter means including a clock pulse generator for generating a train of clock pulses; phase-shifting means for shifting the phase of the train of clock pulses generated by the clock pulse generator of said transmitter means, thereby producing a plurality of reference pulse trains having different phases; clock pulse selector for independently selecting one of said reference pulse trains, the phase difference in time of which is the nearest to the remainder of said delayed timing divided by the period of the clock pulse; a plurality of pulse counters connected to said pulse selectors for counting the reference pulse trains selected by said pulse selectors until reaching the preset value nearest to said delayed timing to produce a trigger pulse; pulsers connected to said transducer elements and said pulse counters for producing, in response to the trigger pulse, a drive pulse to excite the transducer elements; scanning means for achieving a two-dimensional scanning of the object by using said beam; receiving means connected to said transducer means for processing the echo signals to produce a video signal representing the image of the object; and display means for displaying the image of the object by using the video signal.