To estimate carrierfrequency of digitally modulated signal whose modulation type is unknown, a carrierfrequency estimation method for digitally modulated signal is proposed.
The spectrum of amplitude modulated signal are two half magnitude spectrums of base band signal positive and negative shifted by a carrier or R. F. frequency.
调幅讯号之频谱为一半强度基频讯号之频谱分别正负位移一射频或载波之频率。
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At the receiver, the modulated optical carrier can be examined from a frequency filter to render target detection.