Patent ID: 7746971
Filing Date: 2010-06-29
Classification: H03L,H04L

Abstract:
1. A data recovery method for restoring serially transferred data in synchronization with a first clock signal having a first frequency by carrying out over sampling, comprising: a sampling step of over sampling the serially transferred data with multiphase clock signals generated as a result of shifting a second clock signal having a predetermined second frequency that is lower than the first frequency by a predetermined phase each to obtain over sampling data, wherein the second clock signal is generated from a reference clock signal that is independent of the first clock signal and a phase difference of the multiphase clock signals is several times smaller than the period of the first clock signal; a clock pattern generating step of generating a clock pattern, having mutually different phase states according to a data phase state of the over sampling data; a phase state control step of detecting rising and decaying edge positions from the over sampling data to obtain a first phase pattern, comparing the first phase pattern and a second phase pattern generated from the clock pattern, and determining a phase state of the clock pattern and a number of effective data indicating the number of bits to extract from the over sampling data; a phase error detecting step of detecting an average of edge positions within a predetermined period from the first phase pattern and the second phase pattern, and generating a phase error indicating an error with respect to the phase state of the edge position average; and a data selecting step of selecting bits to extract from the over sampling data to restore the data based on the phase state of the clock pattern and the phase error detected in said phase error detecting step.