Electronic ultrasonic sector scanning apparatus and method

An electronically scanned phased array diagnostic system for describing internal structure of a subject by the use of ultrasonic energy. The system includes a transducer unit with an array of ultrasonic energy conversion segments and control circuitry for actuating the segments to direct ultrasonic energy into the subject. Imaging circuitry is included for interpreting electrical return signals produced by the segments in response to ultrasonic echoes. The imaging circuitry includes transmission delay circuits for imposing time delays on the return signals for steering and focusing system echo reception. Each transmission delay circuit includes first and second delay elements for impressing first and second delay time components on the return signals. Each pair of the first delay elements are coupled in parallel with separate transducer elements, and serially combined with a downstream second delay element. The first delay elements provide a portion of the reception steering capability. The second elements provide the remainder of the steering, and the beam focusing, delay components. The system further includes display apparatus responsive to the delayed return signals for producing an image of the subjects internal structure.