Abstract: For use in an ultrasonic pulse-echo apparatus including an ultrasonic wave transducer for transmitting an ultrasonic wave into an object to be examined and for producing a first image signal corresponding to echo pulses reflected from the interior of the object, an improved signal processing means for compensating for brightness varying effects caused by varying the object and for providing a second image signal corresponding to the first image signal, and an X-Y type display device for displaying the image of the object from the second image signal. Compensation for the brightness varying effect is secured by a gain controlled amplifier of which the gain is controlled by a control signal corresponding to the cumulative second image signal of the preceding frame.

Abstract: An ultrasonic diagnostic apparatus is provided comprising a clock pulse generator, and electro-acoustic transducer which responds to the clock pulse from the clock pulse generator to produce an ultrasonic wave, a receiving circuit for receiving the electrical signal from the electro-acoustic transducer, a variable gain amplifier for amplifying the output signal from the receiving circuit, a display device for displaying information corresponding to the signal from the amplifier, and a gain control circuit for controlling the gain of the variable gain amplifier.