| 摘要 |
<p>A device for the scanning of objects by means of ultrasound echography comprises a first ultrasonic transducer (10) which is connected to a transmitter stage (50) for the repeated transmission of ultrasonic signals and to a receiver stage (100, 200) for receiving the ultrasonic echoes which correspond to the most important obstacles encountered by the tramsmitted signals in their propagation direction, said receiver stage comprising a first, known processing circuit (100) and, connected parallel thereto, a second processing circuit (200) which consists of a series connection of a control circuit (210) for the automatic control of the gain as a function of the distance of the echoes, a correction circuit (220) for the correction of transducer diffraction effects, a selection circuit (230) for the selection of a narrow frequency band within the pass-band of the transducer which is centered around a frequency Fc, a logarithmic amplifier (250) and a divider circuit (260) which divides the output of the logarithmic amplifier by a factor proportional to the frequency Fc and whose output signal is applied to a second channel of the display device of the processing circuit (100).</p> |
