COAXIAL TYPE WAVE FILTER HAVING SIGNAL-TO-NOISE RATIO ENHANCING ELEMENT THEREIN

摘要

PURPOSE: A coaxial type wave filter having a signal-to-noise ratio enhancing element therein is provided to improve attenuating characteristic of a frequency signal on other portions than a pass band and reduce a reflected wave of a frequency signal within the pass band. CONSTITUTION: A housing(1) is provided with a plurality of cavities, each having a rectangular parallelpiped shape of predetermined size. The outside of the cavity is surround by a grounding conductor and inside of the cavity is also surround by a grounding conductor. Conductive rods(2a-2f) are connected to the cavity electrically connected to the bottom grounding conductor of the cavity on a lower part thereof, and not connected to a ground surface. A metal plate(4) shields an upper part of the housing. An adjusting screw(5) passes through the shielding metal plate, protruded between resonators and adjusts a coupled amount of the resonators. An RF input/output(6,7) is installed on a side of the housing and inputs and outputs an RF signal. A coupling conductive rod(8) inputs and outputs a signal in the first cavity and the last cavity of the housing. A signal-to-noise ratio enhancing element passes a larger signal and prevents a smaller signal from passing.