PREAMBLE GENERATING METHOD FOR OFDM AND MODULATION CIRCUIT FOR OFDM

摘要

PROBLEM TO BE SOLVED: To provide an orthogonal frequency division multiplex(OFDM) preamble generating method and an OFDM modulation circuit that prevent deterioration in an error rate and detect a symbol timing at a high speed even when preamble signal for AGC is in use. SOLUTION: In the OFDM preamble generating method that generates a burst signal including at least one automatic gain control preamble signal being an OFDM signal used for orthogonal frequency multiplex communication and two synchronizing signals in succession to the preamble signal, the preamble signal and the synchronizing signals are generated based on the same predetermined fixed pattern and a prescribed phase change is given to each latter half of either the preamble signal or the synchronizing signal so as to generate a phase difference of about 180 degrees between the phase of the preamble signal for the latter half area and the phase of a plurality of the synchronizing signals for each latter half area.