Processing method for reproduced signal and circuit therefor

PURPOSE:To realize a processing method for a reproduced signal and its circuit in which a constant converges at high speed and the nonlinear element can be eliminated and adequate equalization can be performed without increasing degradation of S/N and an equalization error, even if amplitude is different depending on polarity of the waveform as in a reproduced waveform of a magnetic head in which a magnet-resistance effect element is a reproducing element. CONSTITUTION:This is a processing method including at least such functions that the target equalizing values Y+ and Y- of an equalizer 1 which automatically equalizes a signal X from a reproducing head are asymmetrically set for positive and negative polarity, and the relevant target value are successively compensated by feeding back an equalization error E which is computed as the difference between the equalizer output Y and the above mentioned target value to the equalizer 1. In addition, a direct current level of the input signal X is shifted by finding a compensation value of a 0 level from the equalization error E, and this method is improved to be a more efficient method by compensating the equalizer output Y using an identified result A of the equalizer output Y and the equalizing target value.