ULTRASONIC WAVE PULSE DOPPLER APPARATUS.

摘要

An ultrasonic pulse Doppler apparatus comprising: range gate means (20) which applies range gating to received echo signals of the individual vibrator elements of an ultrasonic wave probe (1) at individually adjusted moments according to the direction of a received ultrasonic wave beam; pulse stretcher filter means (21) which lengthens the duration time of a plurality of reception signals that are range-gated while conserving the energy of signals; phasing addition means (7a) which adds all of a plurality of output signals of pulse stretcher filter means in phase with one another; detector means (12) which coherently detects an output signal of phasing addition means; and Doppler signal forming means (15), (16) which form Doppler signals based upon the output signals of detector means. The received echo signals are range-gated for each of the vibrator elements, and the range-gated signals are subjected to the phasing addition after their duration time is stretched through a pulse stretcher filter. Therefore, the received signals seldom lie on the limit of a dynamic range of the signal processing circuit.