A signal repeater comprising: a signal processing part comprising: a converter configured to receive an input signal and to convert the input signal into quadrature signals comprising a plurality of polyphase samples; and a processor configured to: calculate magnitudes of each of the plurality of the polyphase samples, and calculate an average magnitude based on the calculated magnitudes, and calculate frequencies of each of the plurality of polyphase samples by conjugate-multiplying, and calculate an average frequency based on the calculated frequencies; and compare the average magnitude and the average frequency of the input signal with a plurality of predetermined characteristics to generate a comparison result; and a signal repeating part configured to selectively repeat the input signal as a repeated signal in accordance with the comparison result, wherein the processor is configured to calculate the magnitude of the input signal according to an equation defined as Magnitude = L + S / 2, where L = largest of I or Q of the quadrature signals, where L = largest of |I| or |Q| of the quadrature signals, and S = smallest of |I| or |Q| of the quadrature signals. a signal processing part comprising: a converter configured to receive an input signal and to convert the input signal into quadrature signals comprising a plurality of polyphase samples; and a processor configured to: calculate magnitudes of each of the plurality of the polyphase samples, and calculate an average magnitude based on the calculated magnitudes, and calculate frequencies of each of the plurality of polyphase samples by conjugate-multiplying, and calculate an average frequency based on the calculated frequencies; and compare the average magnitude and the average frequency of the input signal with a plurality of predetermined characteristics to generate a comparison result; and a converter configured to receive an input signal and to convert the input signal into quadrature signals comprising a plurality of polyphase samples; and a processor configured to: calculate magnitudes of each of the plurality of the polyphase samples, and calculate an average magnitude based on the calculated magnitudes, and calculate frequencies of each of the plurality of polyphase samples by conjugate-multiplying, and calculate an average frequency based on the calculated frequencies; and compare the average magnitude and the average frequency of the input signal with a plurality of predetermined characteristics to generate a comparison result; and calculate magnitudes of each of the plurality of the polyphase samples, and calculate an average magnitude based on the calculated magnitudes, and calculate frequencies of each of the plurality of polyphase samples by conjugate-multiplying, and calculate an average frequency based on the calculated frequencies; and compare the average magnitude and the average frequency of the input signal with a plurality of predetermined characteristics to generate a comparison result; and a signal repeating part configured to selectively repeat the input signal as a repeated signal in accordance with the comparison result, wherein the processor is configured to calculate the magnitude of the input signal according to an equation defined as Magnitude = L + S / 2, where L = largest of I or Q of the quadrature signals, where L = largest of |I| or |Q| of the quadrature signals, and S = smallest of |I| or |Q| of the quadrature signals.