| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter capable of eliminating an interference frequency adjacent to a passband of a band pass filter. SOLUTION: A band pass filter is composed of a serial connect 43 of a secured inductance 41 which is serially connected and formed on a printed circuit board, and an adjustable air-core coil 42, a first capacitor 44 connected to both ends of the serial connect 43, and a second capacitor 46 connected among the secured inductance 41 of the serial connect 43, a connecting point 45 of the air-core coil 42 and a ground. The band pass filter passes a predetermined first frequency using the first capacitor 44 and the serial connect 43. A trap filter in which a predetermined second frequency adjacent to the passband of the band pass filter is eliminated by the secured inductance 41 of the connect 43 and the second capacitor 46, is formed. COPYRIGHT: (C)2005,JPO&NCIPI
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