US Patent 9401800 Clock data recovery system for Serdes

A clock data recovery system is provided. A CTLE generates a first equalized signal. An adder superposes the first equalized signal and a feedback equalization signal and generates a superposed signal. A first error slicer slices the superposed signal according to a clock signal and a reference voltage and generates a first error signal. A second error slicer slices the superposed signal according to the clock signal and a second slicing voltage. A data slicer slices the superposed signal according to the clock signal and a third slicing voltage and generates a data signal. A CDR circuit generates the clock signal. An adaptive filter receives the data signal and the first error signal, and generates the reference voltage and a DFE coefficient set. A DFE receives the data signal and the DFE coefficient set, and generates the feedback equalization signal.