Cardiotachometer
OwnerRudolf Mauser, Horst Chmielinventors
Life of this patent
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Abstract
A pair of doppler type ultrasonic transmitters and receiving devices are employed, one operating at a frequency lower than the other. Each of the devices are connected to a demodulator to produce first and second doppler frequency signals, one indicative of vascular blood flow, the other indicative of movement of the vascular wall. The doppler frequencies are fed to a signal processing circuit and a reference stage received as its input, the output of the signal processors. The reference stage produces an output signal on coincidence of the two input signals which is indicative of the heart-beat frequency.
Claims15
A cardiotachometer for determining heart-beat frequency comprising a first and a second doppler type ultrasonic transmitting and receiving device and a demodulator unit, said first ultrasonic transmitting and receiving device operating on a first frequency f.sub.1 and providing at the output of the demodulator unit a first Doppler-frequency signal .DELTA.f.sub.1 which is indicative of the vascular blood flow velocity;
- said second ultrasonic transmitting and receiving device operating on a second frequency f.sub.2 lower than said first frequency f.sub.1 and providing at the output of the demodulator unit a second Doppler-frequency signal .DELTA.f.sub.2 which is indicative of the movement of the vascular wall;
- a first signal-processing circuit receiving as its input signal said first Doppler-frequency signal (.DELTA.f.sub.1), a second signal-processing circuit receiving as its input signal said second Doppler-frequency signal (.DELTA.f.sub.2), and a reference device receiving as its input signals the output signals of said first and second signal processing circuit, said reference device being adapted to deliver an output signal each time an output signal of said first signal processing circuit arrangement coincides with an output signal of said second signal processing circuit arrangement which is indicative of the heart-beat frequency.
The cardiotachometer according to claims 11 or 27 wherein the second ultrasonic transmitter has an ultrasonic reflection cone having an aperture angle (.beta.) substantially smaller than 90.degree..
Dependencies are inferred from the claim text.