| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize the suppression of deterioration of wireless characteristics while reducing power consumption. <P>SOLUTION: An active filter has AGC amplifiers 11, 13 for amplifying an input signal corresponding to a control voltage value, band pass filters 12, 14 for extracting a signal in a desired frequency band from the input signal, detection rectification circuits 16, 17 for generating an AGC amplifier control voltage value after detecting and rectifying output signals of the AGC amplifiers 11, 13, and a switching control unit 23. Capacitors C1, C2 and C3, C4 respectively having different capacity values are connected to the detection/rectification circuits 16, 17 via switching selection switches 21, 22. The switching control unit 23 controls the switching selection switches 21, 22 corresponding to the presence, the absence or the magnitude of an interfering wave. Consequently, the capacity of the capacitor connected to the detection/rectification circuits 16, 17 can be switched. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
