Abstract: Systems and methods are taught whereby amplification of narrowband signals may be accomplished by linear power amplifiers requiring the presence of a communicated broadband signal in order to make internal adjustments necessary for linear operation. A preferred embodiment is described utilizing an input of a distributed amplifier assembly unused by the signals of interest in order to inject an emulated CDMA tone operable as a pilot tone for use by the linear power amplifiers.

Abstract: An ultrasound imaging system is provided which produces gray scale images of the anatomy simultaneous with Doppler signal processing so as to provide a single real-time image that shows not only the vascular anatomy and surrounding tissue but also flow events in the vascular compartment. A phased linear array having near-continuous focus over the scanning field provides high resolution and very small Doppler sample volumes. The system tests incoming signals from throughout the scanning field for amplitude, phase and frequency so as to determine B-mode data, motion presence and direction, and echo source velocity.

Abstract: An ultrasound blood flow imaging system employing a moving-target-type Doppler processor having a passband extending from zero hertz to the repetition frequency of the pulses generated and processed during each beam. The system is able to image low-velocity blood flow by reducing the frequency at which pulses are generated and processed during each beam, thereby increasing the gain of the flow processor at low frequencies. In order to avoid a corresponding decrease in the frame rate, the ultrasound pulses for several beams are alternately generated and processed in interleaved sequence rather than generating and processing all of the ultrasound pulses for each beam before generating and processing ultrasound pulses for the next beam.