| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio receiving circuit which achieves a tuned circuit with high selectivity even when there are variations in inductors or varactors. Ž<P>SOLUTION: In the radio receiving circuit, capacity values of varactors Cfa, Caa of a front tuned circuit 11 and a tuned circuit 12 at the rear stage of the front tuned circuit 11 are controlled by a control voltage VTO of a local oscillation circuit 13. In addition, capacity values of varactors Cfb, Cab for fine adjustment of the front tuned circuit 11 and the tuned circuit 12 are controlled by control voltages VT1, VT2 to be generated based on an RSSI signal. Thus, influences of variations of capacity values of the varactors of the front tuned circuit 11 and the tuned circuit 12 are suppressed. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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