| 摘要 |
The invention relates to a method for recording ultrasonic echoes occurring during the ultrasonic scanning of objects, e.g. the human body, on the recording carrier of a recording device, it also being possible, in particular, to detect over and above the amount of the acoustic surge in characteristic impedance the polarity thereof, as well as to a device for carrying out this method. In known devices, it is not always possible to characterise the polarity unambiguously. According to the invention, the following conditions are observed in an ultrasonic scanning method which is otherwise conventional: a) on the one hand, the transmitted signal has a defined waveform, and b) on the other hand, the received signal is subjected as a function of the structure of the prescribed transmitted signal to an n-fold summing of the signal, which is respectively shifted by a prescribed amount. Using this method, it is possible in the case of a sinusoidal wave train as transmitted signal to detect only the echo response originating from the positive half wave and, if necessary, to discriminate unambiguously with respect to the polarity of the surge in characteristic impedance. An associated device requires only a device for delaying ( tau ) and n-fold summing of the echo signals. <IMAGE> |
