| 摘要 |
PURPOSE:To obtain a wave transmitter/receiver with varied directivity using the same ultrasonic wave vibrators, by arranging a plurality of wave transmitting/receiving elements to apply signals with the amplitude determined by a specific curve and the position of vibrators into or take them out of the wave transmitting/receiving elements. CONSTITUTION:A plurality of electrodes (a main-electrode 2 and sub-electrodes 3) are put tight on the top surface of a rectangular piezo-electric vibrator 1 and one electrode 4 on the undersurface thereof. A signal curve given by (sin X)/X, wherein X=2piltheta/lambda (wherein l represents electrode length, lambda wavelength of carrier frequency signal, and theta azimuth) and a reference amplitude signal (a) is applied to the electrode 4 through a transformer 5 while a signal having the amplitude of (b) to the main electrode 2 and a signal having the amplitude of (c) to the sub electrodes 3 to emit a signal from the vibrator 1. Conversely, incoming signals are taken out of the electrodes 2-4 and combined to obtain a signal represented by (sin X)X. |
