A continuous-time domain Decision Feedback Equalizer (DFE) for use in a
serial communication channel comprises in one embodiment a summer, a
decision circuit, a capture flip-flop (FF) and an N-th order active
filter. The DFE and its active filter operate in continuous time to give
improved performance over a discrete-time DFE. In one embodiment
involving a first-order active filter, the capture FF is outside the
continuous-time negative feedback loop of the DFE and involves a
differential signal amplifier. In another embodiment, the capture
flip-flop is inside the DFE loop, and in a third embodiment the decision
circuit comprises a comparator.