| 摘要 |
A receiver 1 comprises a tracking filter 9 connected to the signal receiving side of the field effect transistor (FET) 10 of a tracking filter circuit 2 and a frequency converter 3 connected to the tracking filter circuit 2. A control signal is applied from an AGC circuit 15 to the gate of the FET 10 to detect the receiving level of the signal being received. A predetermined tuning voltage is applied from a D/A converter 7 to the tracking filter 9 according to the control signal from a microcomputer 8. When the signal receiving level is high, a filtering characteristic for power matching is selected for the tracking filter 9. On the other hand, when the signal receiving level falls to a certain extent, a filtering characteristic for NF matching is selected for the tracking filter 9 for the tracking purpose. With this arrangement, the signal receivable range is broadened and the signal receiving sensitivity is improved for the receiver 1.
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