| 摘要 |
PURPOSE:To reduce the unnecessary response among received beams, by making an element width larger than the wavelength and giving a negative code to the signal from the element having the code directivity differing from a central element, in phase or excluding said signal from addition. CONSTITUTION:An element having an element width larger than the utilized ultrasonic wavelength is used. Negative codes are added to such element as element belonging to region G1 and G1', of which the directivity with respect to the focus F ob beams is negative with respect to the element E0 located at the foot of the perpendicular line drawn downward from the focus onto the array, or said signal is excluded from addition. |
