| 摘要 |
PURPOSE:To reduce the response of unnecessary frequency at the outside of bands, by using a width longitudinal oscillation ceramic oscillator having different plate thickness for a ceramic filter of ladder constitution. CONSTITUTION:The ceramic filter of ladder form is constituted with ceramic oscillators 1, 1' and a capacitor C. As the ceramic oscillators 1, 1', using the width as lengthwise direction, the ceramic oscillators comprising a piezoelectromagnetic plate 5, metallic thin film electrodes 6a, 6b, 6c, and 6d, separation bands 7a, 7b, and terminals 9a, 9b are used. In using different plate thickness tO for the ceramic oscillators, the resonance frequency of the main oscillation (width longitudinal oscillation fundamental wave) is made equal and the resonance frequencies of the ternary mode and succeeding is made different, the unnecessary frequency response at the outside of band is reduced and the S/N of a filter output signal is improved remarkably. |
