| 摘要 |
PURPOSE:To increase attenuation at both sides of a passing band by setting the capacities of two electrodes of an interdigital electrode, having a small number of couples divided into two and connected electrically in series, at the best ratio. CONSTITUTION:Electrode 1 which has a relatively small number of couples, such as 5-20 couples, and is equal in cross width, is divided into two parts, partial electrodes 4 and 5, at division part 1a. Common part 4b of partial electrode 4 and common part 5b of partial electrode 5 serve as terminals of interdigital electrode 1, and common part 4b is grounded. When the capacity of electrode 4 is denoted as C1 and that of electrode 5 as C2, setting (C2/C1) to 1.03-1.45 improves attenuation at attenuation position which are at both sides of the passing band. |
