An ultrasonic diagnostic apparatus has a probe for transmitting and receiving an ultrasonic wave and an amplitude-detecting circuit, and in operation transmits an ultrasonic wave into an organism while the organism is scanned by the probe and amplitude-detects a received signal reflected from the inside...http://www.google.fr/patents/US4318413?utm_source=gb-gplus-shareBrevet US4318413 - Ultrasonic diagnostic apparatus
