Piezoelectric resonator for use in IF filter for AM receiver

摘要

The resonator formed on a rectangular flat piezoelectric substrate (12) has a front electrode divided into three sections (14a-14c), and an undivided back earthing electrode (16). The divisions (18,20) are parallel to and equidistant from the longitudinal axis. The sections extend throughout the length of the substrate, and the aggregate width of the two outer sections is substantially equal to the width of the central section. Input/output connections (22,24) are made to the two outer sections and the central section respectively of the front electrode. The device is used in at least the final stage of a multi-resonator filter.