| 摘要 |
PURPOSE: To improve the S/N and the resolution by obtaining the frequency characteristics of an ultrasonic wave transmission line from an echo waveform generated by pulse compression processing a transmitted wave, and resetting the frequency transition band of the transmitted wave on the basis of the characteristics. CONSTITUTION: An FM signal forming unit 2 sets the lower limit frequency of the frequency transition band of an FM signal to 0Hz and the upper limit frequency to the twice or more of the nominal frequency of an ultrasonic probe 9, and an FM signal transmitter 3 introduces it as an ultrasonic pulse incident to an element 10 to be detected via the probe 9. Then, the probe 9 receives the reflected wave from the element 10, converts it to an electric signal, and sends it to a pulse compressor 5. The compressor 5 calculates the mutual correlation between the received echo waveform and a reference signal 4, compresses the echo waveform, and sends it to a waveform extractor 6. The extractor 6 obtains the frequency characteristics of an ultrasonic wave transmission line including the probe 9 from the transmitted wave and the compressed echo waveform, and so resets the frequency transition band of the transmitted wave based on it as to optimize the S/N of the echo waveform after the pulse compression. |
