Ultrasonic doppler blood flow velocity detection apparatus.

摘要

A first ultrasonic Doppler blood flow velocity detection apparatus comprises: a signal producing circuit for producing trigger pulses, sampling clock having a given phase relation with the trigger pulses, and a pair of quadrature signals of a given frequency in response to the trigger pulses; a transducer for transmitting ultrasonic waves in response to the trigger pulses and for receiving ultrasonic waves reflected at an ultrasonic-wave reflective objects and converting the received ultrasonic waves into an electric echo signal; a Doppler shift detection circuit responsive to the pair of quadrature signals and the echo signal for detecting Doppler shift; and an averaging circuit responsive to the sampling clock, and the Doppler shift for averaging plural time-different values of the Doppler shift, thereby producing a signal indicative of flow velocity of the ultrasonic-wave reflective object. A second apparatus further comprises a weighting circuit responsive to the output of the Doppler detection circuit, and the sampling clock for weighting every value of the plural time-different values.