Abstract: A phased array of transducer elements in an ultrasound imaging system is selectively directed by grouping transducer elements in the array to form a plurality of groups of adjacent transducer elements. Electrical signals in each group are mixed with a modulation signal of a fixed frequency, the modulation signal being selectively phased delayed for each electrical signal in the group depending on the angle of direction of a reflection point in an imaged volume. The mixed electrical signals for each group are then summed and selectively timed delayed, and then all time delayed and summed electrical signals are then summed to form an image beam.

Abstract: Continuous wave (CW) Doppler imaging employs a linear array of transducer elements with a first plurality of elements functioning as an ultrasonic wave transmitter and a second plurality of elements functioning as a receiver of the reflected ultrasonic wave. Time delay circuitry connected to the transmitter and receiver elements define the beam focus and beam steering of the ultrasonic wave.

Abstract: Disclosed is a wide aperture ultrasonic scanner which requires no moving parts. A convex array of transducer sub-elements is provided. Groups of sequential sub-elements form a transmission/reception element, and groups of transmission/reception elements are activated to form a vector. A plurality of vectors are defined by selectively removing and adding sequential sub-elements forming each element.

Abstract: A scanning system having a variable field of imaging uses a transducer array including a central element and one or more annular elements concentric therewith. The central element is energized at a first frequency for near field imaging, and the one or more annular elements are energized at lower frequencies for intermediate and far field imaging. Electrical signals generated by the transducer elements in response to reflected ultrasonic waves are demodulated to form in-phase and quadrature phase demodulated signals, and the in-phase and quadrature phase electrical signals are then summed to provide an enhanced image signal.

Abstract: Ultrasonic wave attenuation in passing through tissue is determined from frequency changes in reflected ultrasonic waves passing through the tissue. In a baseband ultrasonic imaging system in which transducer generated signals are coherently detected by mixing the signals with a fixed frequency signal both in phase and in phase quadrature, a measure of frequency change in the reflected ultrasonic signal is obtained by measuring phase shift in a side band of the mixed signals.