A method and apparatus for recovering data by a digital audio interface
begins by receiving a stream of biphase encoded data. The processing
continues by determining whether a next transition of a frame of the
plurality of frames occurs during a first, second, or third time window
after a preceding transition of the frame. When the next transition
occurs during the second predetermined time, the digital audio interface
synchronizes to a data rate of the stream of biphase encoded data based
on the next transition and the preceding transition. If, the next
transition occurs during the first or third predetermined windows, the
digital audio interface synchronizes to a data rate of the stream of
biphase encoded data based on the preceding transition edge and a
subsequent transition. When the transition occurs during the third time
window, the biphase encoding is violated, which indicates that a preamble
is being received.