PHASE ROTATION CORRECTING CIRCUIT, DEMODULATOR FOR ORTHOGONAL AMPLITUDE MODULATION SIGNAL EQUIPPED WITH PHASE ROTATION CORRECTING CIRCUIT, PHASE ROTATION CORRECTING METHOD, DEMODULATING METHOD FOR ORTHOGONAL AMPLITUDE MODULATION SIGNAL, AND PROGRAM FOR PHASE ROTATION CORRECTION

摘要

PROBLEM TO BE SOLVED: To perform phase tracking using not pilot data, but transmission data when an orthogonal amplitude modulation signal is transmitted or received.

SOLUTION: A phase rotation correcting circuit has a rotation angle calculation means and a phase rotation means. The rotation angle calculation means calculates a correction rotation angle using one of halves of each of mutually orthogonal I and Q signals obtained by modulating the transmission data. The phase rotation means performs phase rotation by correction rotation angles on IQ coordinates calculated by the rotation angle calculating means for the other of halves of each of the I and Q signals. The rotation angle calculation means 50 includes a buffer 52 which stores a plurality of pairs of signal values of the I and Q signals, a distance calculation means 54 of calculating the distance of each of pairs of signal values stored in the buffer from an origin when they are disposed on the IQ coordinates, a diagonal data decision means 56 of deciding a pair of signal values having the longest distance from the origin calculated by the distance calculation means as diagonal data on the IQ coordinates, and an angle comparison means 58 of obtaining the correction rotation angle from the diagonal data.

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