Abstract: Ultrasonic energy is emitted within a detection envelope from a single transducer and echoes of targets therein are received during scanning displacement of the transducer through a predetermined sweep angle from a zero position on a platform, against the centering bias of springs through which pulse signal current is conducted to and from the transducer. An electromagnetic scanner drive imparts oscillatory motion to the transducer by magnetic generation of displacing forces varied in accordance with its loading at the zero position of the transducer and at limit positions detected by a position sensor to maintain a constant scanning sweep angle in timed relation to pulsing of the transducer through a transmit-receive circuit under preprogrammed computer control.