FDM与OFDM的区别 冬FDM的频谱 frequency Conventional Frequency Division Multiplex(FDM)multicarrier modulation technique OFDM的频谱 Saving of the bandwidth frequency Orthogonal Frequency Division Multiplex(OFDM)multicarrier modulation techniqueFDM与OFDM的区别  FDM的频谱  OFDM的频谱