Electromechanical converter for ultrasonic transmission systems - has interdigitated electrodes inclined to direction of wave propagation to minimise signal phase and amplitude distortion

摘要

An electro mechanical converter stage for use with ultrasonic signal transmissions is designed to minimise phase and amplitude distortion of the transmitted signals. The normal input stage consists of two main coupling electrodes (22, 23) mounted on a piezo-electric substrate (11) and inclined to the required wave propagation direction (4). Finger electrodes (21) are coupled to the main electrodes in a direction perpendicular to wave propogation. Phase and amplitude distortion is avoided by continuation of the main electrodes (122, 123) to the full width of the signal transmittion path (8). The main electrodes are relatively wide, ensuring a low impedance path.