| 摘要 |
PURPOSE:To observe always a high-quality ultrasonic image, by performing the automatic gain control so that a receiving signal has a proper level in relation to the level of this signal. CONSTITUTION:Ultrasonic waves are condensed onto a sample to scan it two- dimensionally, and a detecting means 15 receives ultrasonic waves reflected by the sample or transmitted through it and detects them. A signal processing system 21 includes a scan converter 17 which converts the attained detection output signal to a picture signal whose amplitude corresponds to the luminance of the scanning position due to two-dimensional scanning of the sample. A means which makes a picture signal visible makes the picture signal from this sample information signal processing system visible as an ultrasonic image of the sample. A gain control means 25 is inserted to the input side of the detecting means 15, and this gain control means is controlled automatically by a gain control signal attained by processing the detection output signal, thereby holding down the detection output signal level within a prescribed value. |
