| 摘要 |
An ultrasonic, transcutaneous blood flow detector. A protective mounting cup is positionable against the skin of a patient for the transfer of ultrasonic energy into and out of the patient's body. The detector utilizes only a single piezoelectric transducer with a first face in juxtaposition with an interior face of the cup. A film of viscous semifluid material is positioned between the transducer first face and the cup's interior face to couple ultrasonic energy between the transducer and the cup. A resilient spring or foam member resiliently biases the transducer first face into engagement with the cup's interior face with the semifluid material therebetween, thus permitting substantially uninhibited deformation of the transducer in response to a drive signal. A transmitter supplies a continuous wave drive signal to the transducer, and a detector circuit operating concurrently therewith detects the Doppler frequency shifted electrical signal generated by the transducer as a result of the Doppler frequency shifted acoustic energy reflected back to the transducer. The transmitter provides the drive signal to the transducer with an output voltage automatically variable in response to loading of the transducer with reflective energy. An amplifier and audio binaurals provide a variable pitch audible tone to the user.
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