Abstract: A device for eliminating fixed echoes for an ultrasonic echograph, comprising a first filter (100) which consists on the one hand of M parallel lines i (i=1, . . . , M) which a respective delay (i-1)T, where T is the repetition period of the echograph, and on the other hand of weighting means (101i) for the M lines i, the sum of the coefficients (a.sub.i) applied to said lines being zero and, of an adder (102) for the lines i thus delayed and weighted. In accordance with the invention, at least one second filter (200) which has the same structure as and which is dephased by (M-1)T with respect to the first filter (100) is connected parallel to the first filter (100), the pulse response (h.sub.2 (t)) of the second filter being linked to the pulse response (h.sub.1 (t)) of the first filter as:h.sub.2 (t)=h.sub.1 (m-1)T-t).Application: Measurement and imaging of blood flow speeds by ultrasonic echography.

Abstract: An instrument for measuring blood pressure by sensing the Korotkoff sounds which prevail only between the systolic and diastolic point. The instrument used is essentially a hand-held device. The instrument has a pressure-sensitive element made up of a flexible material containing fluid and crystal transducer supported on the flexible material which responds to the Korotkoff sounds. The sensor is made in a unique geometrical structure shaped to fit between bones and tendons over an artery. The crystal operates through an amplifier, a high pass filter and low pass filter through a comparator to a one shot enabling means connected to a panel meter. The pressure on the fluid in the sensed by a pressure sensor that is in contact with the fluid in the sensor which is connected to the panel digital meter. The digital display shows the pressure exerted on the artery at each Korotkoff sound. A LED shows that pulses are present.

Abstract: Apparatus and technique for monitoring physiological parameters. An acoustic sensor or microphone is placed in close proximity to the chest of a patient having one or two prosthetic heart valves. These heart valves produce clicks characteristic of opening and closing action. The acoustic sensor picks up the sound of these clicks and transfers them as electrical energy to a transmitter unit. The transmitter unit processes the analog signal, converts it to a digital signal and establishes the key timing factors involved. This digital data is stored in a memory buffer within the transmitter. Subsequently, this information is modulated and placed on telephone lines for transmission to a central monitoring site. At the monitoring site a demodulator returns the data to baseband digital signals. A computer at the central monitoring site displays the information in the time domain and also converts the information for display in the frequency domain.