Front end processor for data receiver and Nonlinear distortion equalization method

PURPOSE: A front processor is provided to have a nonlinear distortion equalizer reducing nonlinear distortion when complex signal is input according to nonlinear distortion. CONSTITUTION: An OFDM(Orthogonal Frequency Division Multiplexing) base band signal undergone with a synchronization carrier modulation or a differential carrier modulation is inputted to a complex signal converter for compensating nonlinear distortion(102) and is converted according to the N-th function conversion characteristics(N>1) with compensating nonlinear distortion in the OFDM baseband signal. The values for an input signal, an output signal, and a coefficient for compensating m-th distortion are x(c), y(n), and am(n) respectively at time n, and accordingly a conversion numerical formula is y(n)=x(n)+sigma am(n) x¬m(n)(m>1). 비선형왜곡 보상용 복소신호변환기는, 동기캐리어변조 또는 차동캐리어 변조된 0FDM 베이스밴드신호를 입력하여, N차함수변환특성(N > 1)에 의해서 변환한다. 그리고 OFDM 베이스밴드신호내의 비선형왜곡을 보상한다. 이 때 입력신호, 출력신호, 및 m차왜곡 보상용계수의 시간 n에서의 값을 각각 x(c), y(n), a(n)로 하면, y(n) = x(n) + Σa(n) x(n) (m > 1) 를 변환식으로서 사용한다.