on the selected number of sampling points per data bit the number of comparators used in the directive generator 56 may depend on achieving a desired result thus the number of comparators given below should not be construed as a limitation but rather should be construed as aiding in the understanding of the directive generator 56 operation an operation involving two sampling points per data bit is now described two comparators may be used to compare three consecutive sampled data in a serial data stream to generate two compare results the directive generator 56 determines whether to output an increment directive or a decrement directive based on whether a first comparator or a second comparator of the two comparators outputs a u201c 1 u201d for example if the first comparator outputs a u201c 1 u201d this may indicate a phase lead condition where the input serial data stream is drifting to be u201c slower u201d than the clock generated by the clock generator 42 conversely if the second comparator outputs a u201c 1 u201d this may indicate a phase lag condition where the input serial data stream is drifting to be u201c faster u201d than the clock thus when a phase lead condition is detected the directive generator 56 outputs.