| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication receiver equipped with an automatic gain control circuit section that absorbs level fluctuation of a received signal so as to receive a signal in stable level. SOLUTION: An RF signals received by an antenna 1 is given to an RF section 2, where the signal is mixed to attain an IF signal. The RF signal received by an RSSI circuit 4 of an automatic gain control circuit section 9 is converted into a DC component to detect a reception electric field strength. A level discrimination device 8 provides a threshold level characteristics to an input level and the input level controls a variable amount of a gain variable device 3 to control the gain. The signal whose gain is controlled is converted into a digital signal by an A/D converter 5. The digital signal is given to an averaging processing circuit 6, where the signal is averaged at an optional time T to control a variable amount of the gain variable device 3 to be converged into the digital signal denoting N-bits of an optional amplitude level. A base band section 7 decodes the digital signal into information before modulation processing at a transmitter side.
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