Patent ID: 8204168

Claim:
A communication apparatus for receiving a signal train from a transmission line, said signal train being comprised of a first signal period including a sequence of alternating “1” and “0” bits and a second signal period succeeding the first signal period, the communication apparatus comprising: a clock generator for generating an internal reference clock; a multi-phase clock generator for generating multi-phase clocks including a plurality of clocks different in phases based on said internal reference clock; an initial phase determining unit, to which said multi-phase clocks and a signal of said first signal period are supplied, for determining one of said multi-phase clocks as a phase clock to be used for retiming said signal train; a clock selector, to which said multi-phase clocks and an instruction from said initial phase determining unit are supplied, for outputting a specific phase clock selected from among said multi-phase clocks; and a phase tracking unit for outputting phase difference information indicating phase difference between a signal of said second signal period and said specific phase clock outputted from said clock selector, wherein said clock selector selectively outputs, as said specific phase clock, a phase clock specified by said initial phase determining unit or one of the other phase clocks selected from among said multi-phase clocks depending on the phase difference information supplied from said phase tracking unit.