| 摘要 |
PURPOSE:To allow the device to have high resolution and high sensitivity by providing plural vibration elements which have a prescribed angle against the arrival direction of a chirp pulse, and in which the moving wave front is placed so that the polarity coincides, a connecting means for positive and negative electrode phase components of the vibration element, and a subtracting for the positive and negative electrode phase components. CONSTITUTION:Vibration elements 12al-12an, 12bl-12bn are placed by holding a prescribed angle against the acoustic wave arrival direction of a chirp wave, and varying gradually an interval of the adjacent vibrators in accordance with a frequency variation rate of a chirp. In an instant being in a state that a housing chiarp wave which is reflected from a living body and returned is shown in a figure against a vibrator main body 11, the part of minus and plus acoustic pressure of a chirp acoustic wave reaches the vibration element 12al-12an, 12bl-12bn, and from each vibration element, a voltage being proportional to acoustic pressure is generated. The voltage is applied to a subtracter 15 by signal lines 13, 14 and subtracts a minus voltage of the signal line 13 from a plus voltage of the signal line 14. As for this output voltage, the chirp waves are all contributed and it becomes a positive maximum value, and a pulse compressing signal of maximum width is obtained. |
