| 摘要 |
Mechanical filters composed of mechanical resonators previously individually trimmed to design resonance frequencies, which are coupled to each other in succession by mechanical coupling elements, are subjected to trimming after assembly as determined by measurement of the coupled oscillations of the completed filter. This measurement is carried out under control of a computer appropriately linked by other equipment to the filter transducers. The computer identifies the frequencies of coupled oscillations and their differences from design values, and calculates the variation from design values of one or more elements of the corresponding filter matrix. By these values the computer develops settings for a trimming device for successively trimming elements of the filter such as resonators, or coupling elements, or both. In the most simplified arrangement and method, only variations of the null condition of one matrix element are considered, and the derived corrections are applied in equal parts to each of symmetrically disposed paired coupling elements. |
