| 摘要 |
PROBLEM TO BE SOLVED: To enable a spurious component reducing circuit to effectively suppress the radiation and mixture of a spurious component, without losing a main signal. SOLUTION: A series circuit composed of a resistance R and an LC parallel circuit 2, having parallel resonance at a main signal frequency fr, is connected to a main signal line 1 in parallel and an LC series circuit 3 which has series resonance at a spurious frequency fs is connected with respect to the LC parallel circuit 2 in parallel. High impedance is obtained at a point (b) to a main signal fr through the parallel resonance of the LC parallel circuit 2, so the resistance R becomes invisible from a point (a), and so that no influence is exerted on the main signal line 1. As for signal components of other frequency, the impedance at the point (b) decreases, so the signals are attenuated by the resistance R when passing the point (a). The point (b) is equivalently grounded, specially with respect to a spurious frequency fs through the series resonance of the LC series circuit 3, so that spurious components passing the point (a) are fully attenuated by the resistance R.
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