| 摘要 |
PURPOSE: An auto gain control circuit is provided to drastically reduce a size of a circuit by applying the auto gain control circuit in comparison with the use of a conventional λ/4 micro strip line. CONSTITUTION: An auto gain control circuit includes a signal splitter for outputting a power with splitting the power corresponding to a predetermined portion of an output power of the circuit, a power detector for comparing the power from the signal splitter with a predetermined reference power and outputting the output value to a voltage signal in response to the comparison result, a low pass filter for outputting a direct current component of the control voltage by filtering the alternative characteristics of the voltage signal from the power detector, an amplifier for amplifying the control voltage from the low pass filter and for outputting the amplified control voltage to a predetermined level and an attenuator for configuring a circuit to match an impedance between an input terminal and an output terminal by using concentration circuits. The attenuator implements the attenuation by using a pin diode, transmits the input power to the output terminal by attenuating in response to the control voltage from the amplifier.
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