Abstract: Current-responsive light-emitting diodes of different colors are provided adjacent to the tip of the hand-held transducer probe of a medical Doppler device. Mechanism is provided to actuate the diodes of one color when the direction of internal body matter detected by the Doppler device is toward the probe and to actuate lights of a different color when the direction of detected internal body matter is away from the probe. In addition, power supply to the diodes is controlled so that increasing brightness indicates increasing velocity of the detected internal body matter.

Abstract: During a surgical operation, a conventional electroencephalograph provides several analog electrical signals of the brain waves of the patient, each signal indicating voltage fluctuations detected at a different area of the patient's scalp. The analog signals are converted to digital form for input to a multipurpose computer. The computer is programmed to produce respective reference traces on a video monitor indicating the voltage fluctuations detected during a preceding reference period. While the reference traces continue to be displayed, more current traces are produced on the video monitor in juxtaposed relationship to the reference traces. The current traces indicate the voltage fluctuations detected during the period immediately preceding their display. The current traces are replaced periodically with new current traces indicating more recent information. Any significant change in the patient's brain waves is detected by comparing the current traces with the reference traces.

Abstract: The analog broadband output signal of a medical Doppler device is sampled at a constant rate to convert the signal to digital form. The sample values are stored consecutively in a random access memory component. Such values are recalled from such component at a readout rate different from the sampling rate so as to create a frequency-shifted intermediate broadband signal corresponding to the Doppler output signal. Such intermediate signal is filtered and the power of the filtered intermediate signal is continuously compared to the power of the unfiltered intermediate signal. The readout rate from the memory component is adjusted to maintain approximately the same proportionate relationship of the power of the filtered intermediate signal to the power of the unfiltered intermediate signal. The continuously adjusted readout rate from the memory component indicates a "band edge" frequency above or below which a preselected proportion of the total power of the Doppler signal resides.

Abstract: Side-by-side transmitting and receiving transducers of a medical Doppler ultrasound device are covered by a converging lens of synthetic rubber material through which the speed of ultrasound waves is slower than the speed of the waves in soft body tissue. The lens has a planar inner face butted against the planar transmitting and receiving faces of the transducers and a convexly curved outer face including two portions each extending over both transducers, one of such portions being smaller and more sharply curved than the other. The composite lens focuses the transmitted ultrasound waves in two zones overlapping in range so that the same transducer arrangement can be used in obtaining velocity information from deep or shallow blood vessels.