| 摘要 |
PROBLEM TO BE SOLVED: To improve the time response of an ultrasonic diagnostic apparatus for receiving/transmitting encoded signals. SOLUTION: This ultrasonic diagnostic apparatus comprises an ultrasonic search unit, a transmitting part for transmitting encoded carrier signal to a subject via the ultrasonic search unit, a receiving part for receiving an echo signal from the subject via the ultrasonic search unit, and an acoustic information operating part for operating the acoustic information on the subject based on the output signal of the receiving part. The receiving part comprises a variable filter for reducing the frequency component which interferes with the code demodulation of the echo signal and a code demodulation means for code-demodulating the output signal of the variable filter. By reducing the harmonic component generated by the effect of the non-linear distortion when an ultrasonic signal is propagated through the subject by using the variable filter, the time side lobe of the demodulation signal is reduced and the time response can be improved. COPYRIGHT: (C)2004,JPO
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