| 摘要 |
PURPOSE:To simplify the hardware in a multi-value quadrature amplitude modulator (QAM) system radio communication system by inserting forcibly a carrier for regeneration in a signal component in a prescribed band limit. CONSTITUTION:Two pilot signals Cr1, Cr2 in frequency f0+ or -fCL/N (N>=2) are added to a multi-value QAM signal in carrier frequency f0 and clock frequency fCL and transmitted. The signals Cr1, Cr2 are extracted by BPFs 51, 52 at a receiving side and applied to a modulator 53. Since a signal in frequencies 2f0, (2/N)fCL is obtained at an output of the modulator 53, the signal is extracted by BPFs 54, 56, frequency-divided by frequency dividers 57, 55 and frequencies f0 and fCL are obtained, respectively. Further, a signal having a frequency of fCL/N is obtained from an output of a frequency divider 59 and this signal is eliminated from an output SB of a detector 58. |
