| 摘要 |
A low-pass filter comprises, a parallel circuit of a first coil (L1) and a first capacitor (C1) disposed between an input terminal (P1) and an output terminal (P2); a second capacitor (C2) disposed between the input terminal (P1) and ground (GND); a third capacitor (C3) disposed between the output terminal (P2) and ground (GND); a power detection coil (L3) magnetically coupled to the first coil (L1), both ends of which are detection signal output terminals (P5, P6). Therefore, the low-pass filter enables a decrease in the number of mounted parts in a high-frequency transmission circuit of a digital portable telephone, thereby miniaturizing the circuit and reducing the costs. <IMAGE> |
