| 摘要 |
A frequency shifting circuit suitable for a digital demodulator in a multi-carrier communications system is disclosed. After converting analog signal vectors (I, Q) to the input signal vectors according to a predetermined sampling clock, control data (D-1, D0, D1, ... D11) is generated from a frequency difference between sub-carrier bands and center carrier band. A signal vector rotator (102, 104) is provided corresponding to each of the sub-carrier bands and rotates the input signal vectors on the I-Q plane by an angle determined depending on corresponding control data to shift the sub-carrier bands of the input signal vectors to the center carrier band. A band-pass filter passes an output signal vector of the center carrier band. <IMAGE> |
