| 摘要 |
PROBLEM TO BE SOLVED: To reduce the transmission loss of a passing band by preparing the pairs of serial resonance circuits between the same place of signal transmission line and an AC ground point respectively so as to resonate with the frequency levels which are different from a transmission signal frequency. SOLUTION: If the desired transmission signal frequency is set at f0 , a serial resonance circuit 1A of resonance frequency (f0 +Δf1 ), consisting of a coil L1 and a capacitor C1 and a serial resonance circuit 1B of a resonance frequency (f0 -Δf1 ), consisting of a coil L1' and a capacitor C1' are connected between identical place of a transmission line 10 and an AC ground point respectively. Similarly, a serial resonance circuit 2A of a resonance frequency (f0 +Δf2 ), consisting of a coil L2 and a capacitor C2 and a serial resonance circuit 2B of a resonance frequency (f0 -Δf2 ) consisting of a coil L2' and a capacitor C2', are connected at a place set away from the place, where the circuits 1A and 1B are connected at a place separated by 1/4 wavelength of the frequency f0 . Then a pair of serial resonance circuits nA and nB are connected at a place set away from the preceding place by n/4 wavelength. The unwanted signals resonated by those resonance circuits are led out to the ground, and only the desired signals are transmitted with a low loss.
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