Patent ID: 8750443

Claim:
A phase error estimator, for estimating a phase error in an inputted base band electric signal and feeding back said phase error; said phase error estimator comprising: a pre-decider, for judging a phase of data in said base band electric signal in accordance with said feedback phase error; a phase error complex value extracting section, for extracting a real part and an imaginary part of the phase error in accordance with the judgment result of said pre-decider; a phase error determining section, for determining said phase error in accordance with the real part and the imaginary part of the phase error extracted by the phase error complex value extracting section; and a time delay feeding back section, for delaying said phase error by N number of symbols and feeding back the delayed phase error to said pre-decider, wherein N is an integer greater than 1, wherein said phase error complex value extracting section extracts the real part w 2 and the imaginary part w 1 of said phase error in the following manner: when said pre-decider judges the phase of said data to be π/4, w 1 =Q−I, w 2 =I+Q; when said pre-decider judges the phase of said data to be 3π/4, w 1 =Q−I, w 2 =Q−I; when said pre-decider judges the phase of said data to be 5π/4, w 1 =I−Q, w 2 =−I−Q; when said pre-decider judges the phase of said data to be 7π/4, w 1 =Q+I, w 2 =I−Q; wherein I is a cophase component of said inputted base band electric signal, and Q is a quadrature component of said inputted base band electric signal; said phase error determining section comprises: a first noise removing device, for removing noise in the real part of the phase error as extracted by said phase error complex value extracting section; a second noise removing device, for removing noise in the imaginary part of the phase error as extracted by said phase error complex value extracting section; and an argument calculator, for acquiring an argument in a complex signal formed by the real part having been removed of noise via the first noise removing device and the imaginary part having been removed of noise via the second noise removing device, and determining said argument to be said phase error.