| 摘要 |
PROBLEM TO BE SOLVED: To realize increasing of an amount of speaking calls by improving a receiving quality at a receiving field time of large amount of the speaking calls by preventing a C/N from being deteriorated at the receiving field time of the small amount of the speaking calls. SOLUTION: A controller 5 monitors the value of a digital intermediate frequency signal S4 by receiving the digital intermediate frequency signal S4, generates a gain control signal S5 so that the input level of an A-D converter 40 becomes a predetermined level, and controls an AGC amplifier 37. Further, the controller 5 estimates the receiving field value based on the gain control quantity of the AGC amplifier 37, judges whether the receiving field is low or high by comparing the received field estimated value with a preset threshold value, and prevents the C/N from being deteriorated due to the frequency conversion by controlling a switch 36 so as to pass through an intermediate frequency SAW filter 34 when the low received field is judged. When the high receiving field is judged, the switch 36 is controlled so as to bypass the intermediate frequency SAW filter 34 to reduce an EVM. The receiving quality is improved so that the amount of the speaking calls can be increased. COPYRIGHT: (C)2004,JPO&NCIPI
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