Sampling phase selection method for a stream of data bits

A sampling phase selection method for a data stream, wherein the data stream has a variable data rate in a fixed time period, the method comprising:

• generating a calibration signal, wherein a time interval of the calibration signal is longer than the fixed time period of the data stream;
• generating a first clock sequence and a second clock sequence at a rising edge of the calibration signal, wherein the first clock sequence and the second clock sequence are composed of a plurality of continuous clock phases and a number of the clock phases of the first clock sequence are the same as that of the clock phases of the second clock sequence;
• selecting one of the clock phases of the first and the second clock sequences, in turn, to provide a sampling phase;
• performing a plurality of samplings on the data stream in accordance with the sampling phase to generate a flag signal;
• and
• selecting a final sampling clock phase according to the flag signal with different sampling phases.