An integrated receiver supports adaptive receive equalization. An incoming
bit stream is sampled using edge and data clock signals derived from a
reference clock signal. A phase detector determines whether the edge and
data clock signals are in phase with the incoming data, while some clock
recovery circuitry adjusts the edge and data clock signals as required to
match their phases to the incoming data. The receiver employs the edge
and data samples used to recover the edge and data clock signals to note
the locations of zero crossings for one or more selected data patterns.
The pattern or patterns may be selected from among those apt to produce
the greatest timing error. Equalization settings may then be adjusted to
align the zero crossings of the selected data patterns with the recovered
edge clock signal.