Abstract: Sag of a power signal delivered to of an amplifier is controlled. The maximum amount of sag is limited to limit crossover distortion. A measuring circuit monitors an observed signal to generate a measured signal. A sag control circuit receives the measured signal and one or more input control signals, and in response generates a sag control signal. A regulator circuit receives the sag control signal and a raw power supply signal and in response generates a regulated DC power supply signal for the amplifier. The regulator circuit decreases the maximum power available to the amplifier as the sag control signal magnitude increases, so as to increase distortion and compression in the output signal (e.g., and achieve a "warm", "airy" or "forgiving" sound quality resembling or improving the sound of a vacuum tube amplifier).

Abstract: An ultrasound system automatically measures fetal head size from ultrasound images. An ultrasound image of the fetal head is detected. A radial maxima point is identified on each of a plurality of radii extending from a substantially common vertex point within the fetal head image. Each radial maxima point corresponds to an ultrasound sample along its corresponding radius, and has a maximum ultrasound echo strength. A first curve is defined from the radial maxima points. The remaining unfiltered radial maxima points are fit to a second curve, and the second curve is the detected curved boundary. The detected curve boundary is modified to define an initial fetal head boundary. An inner fetal head boundary and outer fetal head boundary are derived from the initial fetal head boundary and a predetermined fetal skull thickness, and fetal head size is computed from the inner fetal head boundary and the outer fetal head boundary.

Abstract: An ultrasound signal processing apparatus provides a programmable platform for various clinical ultrasound applications. The apparatus is part of an ultrasound medical diagnostic imaging system. Data is processed in real-time, near real-time or in delayed playback. In one embodiment a pair of multi-processors are coupled to shared memory via a cross-bar switch. System control data is input via a VME interface. Ultrasound data is input via frame buffers. A first multi-processor manages vector data transfers and scan-converted data acquisitions. A second multi-processor manages video data output. The two multi-processors split signal processing tasks. In various configurations the apparatus executes vector processing, scan conversion, image processing and/or video processing tasks.