Patent ID: 7978801

Claim:
A clock and data recovery method, comprising: oversampling an input data stream at a data rate by using a reference clock signal at a clock rate higher than the data rate, producing an oversampled stream; tracking the input data stream by locating transitions between adjacent samples of the oversampled stream and moving a no-transition area within the oversampled steam wherein no transitions between adjacent samples are found, wherein th tracking uses a search window of a subset of the oversampled stream samples, centered with respect to said input data stream; and recovering a data signal as a central portion of the no-transition area and recovering a clock signal by dividing the reference clock signal, wherein the method includes: a first search state, wherein said subset of oversampled stream samples corresponding to said search window are checked in order to find said no-transition area: when said no-transition area is found, the method switching into a second track state, wherein said subset of oversampled stream samples corresponding to said search window are checked to verify that no-transition occurs between adjacent samples, and analyzed to track the input data stream aligning accordingly to said reference clock signal, the method coming back to said first search state when a transition occurs, wherein said first search state comprises: an initialising sequence; a main loop to count a number of times without any transition in said input data stream; a first auxiliary loop to count a number of a first driving command (SLIP) with respect to a number of said oversampled stream samples; a second auxiliary loop to verify whether a minimum eye aperture condition is verified; and the method providing a first and second output conditions from said first search state corresponding to a change of state and to an alarm for no eye aperture found.