PEAK/AVERAGE VALUE RATIO REDUCTION METHOD BY PHASE CONTROL OF A MULTI-SUBCHANNEL SIGNAL

摘要

PURPOSE:To reduce the peak/mean value ratio of a transmission signal by adjusting the initial phase of a subchannel modulation signal to a prescribed value. CONSTITUTION:Serial data are converted into M-sets of parallel low speed subchannel bits by a serial/M parallel converter 51. Each subchannel has a pilot symbol insertion circuit 53 and an orthogonal converter 56 or the like respectively and a subchannel signal is fed to a multiplexer 57 via a phase shifter 86 and a transmission signal is obtained, The phase shifter 86 adjusts the initial phase of the subchannel signal and the peak value of a composite signal is minimized by cancelling each pilot signal. Thus, the peak/mean value ratio of the transmission signal is reduced, a small power amplifier is enough for the purpose and data communication immune to noise with a high efficiency is implemented.