Abstract: A dual mode color Doppler imaging system using a linear array of transducer elements generates and transmits into an organism, such as the human body, an acoustic imaging beam optimized for B-mode imaging and a separate acoustic Doppler beam which is steered at preselected angles relative to the imaging beam and is optimized for Doppler data acquisition. Acoustic imaging echoes are acquired and displayed as a B-mode gray-scale image. Doppler data are acquired from multiple sample volumes along the direction of each Doppler beam. The Doppler information acquired along multiple lines is displayed as a color-encoded image that is spatially coordinated with, superimposed upon and simultaneously displayed with, the B-mode gray-scale image.

Abstract: An acoustic imaging system having an array of N transducers arranged for transducing transmit electrical signals into acoustic pulses and for transducing acoustic pulse echos into electrical receive signals has a transducer multiplexer that connects in substantially cyclic order any one of a selected group of M adjacent transducer elements to one of a plurality of substantially identical transmit or receive channels. Each channel includes phase changing means for dynamic focusing, such as a mixer driven by one of a plurality of individually phased clocks. A control demultiplier orders connection of an appropriate one of the differently phased clocks to the mixer of each channel in an order precisely corresponding to the cyclic ordering of the transducer connections by the transducer multiplexer as groups of M adjacent transducer elements are selected to form acoustic scan lines stepped across the entire array.

Abstract: A phased array acoustic imaging system including an array of electromechanical transducers, a dedicated signal processing channel for each transducer and electronic control and delay circuits for them, transmits to and receives ultrasonic energy from a body in a controlled, steered and focused fashion. The electronic delay circuits use a unique cyclically symmetrical arrangement of identical delay cells, each with an electronically variable delay element and each dedicated to a receive signal derived from at least one transducer, to form a summing delay line. The individual delay cells are switched under microprocessor control for efficient combined linear-sector scanning or linear or sector scanning alone. The system includes means to achieve dynamic focusing and dynamic apodization in conjunction with the delay cell architecture.

Abstract: A system is provided in which an analog storage device stores, delays, and/or changes the time scale of an input analog waveform. The system provides an output which is corrected for the gain and offset of the analog storage device by exercising the system using known analog inputs and combining the output so obtained with the uncorrected output of the input analog waveform. In a preferred embodiment, the output is also corrected for non-linear and dispersive distortion of the storage device by exercising the system using an input analog signal derived from the earlier output of the system (corrected for gain and offset) and suitably combining the new output so generated with the earlier output.

Abstract: An array of transducers is provided for transmitting pulses of ultrasonic pressure waves into a body and translating reflections received into corresponding pulses of electrical waves. Phase changing means, which may preferably include heterodyning means, are connected between each transducer and selected taps on one delay line. The taps are just close enough together to provide reasonable overlap of the pulses of electrical waves at the summing point at one end of the delay line. Focussing is attained by adjusting the phases of the waves applied to each tap so that the cycles of carrier wave within the overlapped portion of the pulses at the summing point have reasonable phase coherence.