AMPLITUDE-PHASE CONVERTER AND AMPLITUDE-PHASE CONVERTING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an amplitude-phase converter in a receiver of a multi-valued QAM (quadrature amplitude modulation) system which can be miniaturized, and an amplitude-phase converting method using the amplitude-phase converter.;SOLUTION: The amplitude-phase converter is provided in a multi-valued QAM system with a dividing section for dividing an I signal and a Q signal, an approximate value calculating section for obtaining an approximate value of arc tangent of the division result from the division result of the dividing section, and a phase converting section for converting the output of the approximate value calculating section into phase information. The approximate value calculating section is constituted so as to have a memory in which the tangents of angles which a plurality of straight lines having the equal angular difference and crossing the origin of an I-Q plane form with respect to an I-axis or a Q-axis are stored as addresses, and in which the angles which the plurality of straight lines having the equal angular difference and crossing the origin of the I-Q plane form with respect to the I-axis or the Q-axis are stored as data.;COPYRIGHT: (C)2004,JPO