US Patent 9559880 Eye modulation for pulse-amplitude modulation communication systems

The present invention is directed to communication systems. More specifically, embodiments of the present invention provide a technique and system thereof for performing eye modulation. Eye modulation is performed at the transmission side of a PAM communication system to compensate for distortion and non-linearity and generate an output waveform. Spacing among eye levels is adjusted by performing symmetric modulation using α parameter and asymmetric modulation using β parameter. A correction module measures the output waveform and sends feedback signals to a control module to adjust the α parameter and the β parameter. There are other embodiments as well.