AGC CIRCUIT FOR SECURING POWER OF RECEIVING SIGNAL

摘要

PURPOSE: An AGC(Automatic Gain Control) circuit for securing a power of a receiving signal is provided to prevent a clipping irrespective of a PAR(Peak to Average Ratio) characteristic of receiving data and a characteristic of a channel. CONSTITUTION: An ADC(Analog to Digital Converter)(201) converts an inputted analog signal into a digital signal. The first arithmetic unit(202) obtains a power of the digital signal. The second arithmetic unit(203) obtains a mean to the power. A clipping error rate/optimum threshold determining logic(204) responds to the power and the mean power obtained the first and second arithmetic units(202,203) and determines a clipping error rate of the ADC(201) and a threshold. A comparing unit(205) compares the mean power from the second arithmetic unit(203) with the threshold. A gain control unit(206) increases or decreases the gain of an analog amplifier(207) according to the compared result from the comparing unit(205). The third arithmetic unit(208) obtains a power of a signal filtered in a BPF(Band Pass Filter)(212). The fourth arithmetic unit(209) obtains a mean to the power. A power compensating unit(210) compares the mean power to the signal before filtering transmitted from the second and fourth arithmetic units(203,209) with the mean power of the filtered signal, and generates a control signal for compensating the power. A shifter(211) responds to the control signal generated in the power compensating unit(210) and enhances the power of the signal filtered in the BPF(212).