| 摘要 |
PURPOSE: An AGC(Automatic Gain Control) circuit for a repeater is provided to maximally reduce cross modulation and saturation phenomenon generated in the repeater by an RF(Radio Frequency) signal of a strong electric field by comparing a level of the relayed RF signal with a predetermined reference voltage, automatically adjusting the gain of the repeater, and uniformly maintaining the level of the RF signal. CONSTITUTION: The first and second duplexers(110,180) have a transmission and reception channel, filter receiving RF signals received through the first and second antennas(100,190), and output the RF signals through the first and second antennas(100,190). A pre-amplifying unit(120) amplifies the RF signal received from the first duplexer(110). An AGC unit(130) adjusts a gain of the RF signal outputted from the pre-amplifying unit(120) according to a gain control association signal. An amplifier(140) and a filter(150) amplify the RF signal outputted from the AGC unit(130) and filter only an RF signal of a desired band. A driving amplifier(160) amplifies the RF signal outputted from the filter(150) at a uniform level and provides the amplified RF signal as a transmission RF signal to the first and second duplexers(110,180). A coupler(170) compares the level of the RF signal outputted from the driving amplifier(160) with a predetermined reference signal, and feeds back the compared result signal as the gain control association signal to the AGC unit(130).
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