| 摘要 |
<p>A device for the scanning of media by means of ultrasound echography, comprising at least one ultrasonic transducer (10) which is associated with a transmitter stage (50) and with a receiver-stage which comprises a conventional first processing circuit (101, 102, 103) and a second processing circuit which is connected parallel thereto and which comprises a series connection of a circuit (210) for automatic gain control as a function of the distance of the echos, a heterodyne circuit (230), and n parallel channels, each of which comprises a series connection of a circuit for the correction of diffraction effects, a filter (240a . . . 240n) for selecting a narrow frequency band from the pass-band of the transducer, a logarithmic amplifier (250a . . . 250n) and a divider (260a . . . 260n) whose output is connected to one of the n inputs of a circuit (270) for determining values whose output is connected to the display device provided in the first processing circuit.</p> |
