| 摘要 |
PURPOSE:To prevent the generation of cross modulation and spuriousness by generating the signals of different center frequencies by applying digitally a frequency offset in a base band zone. CONSTITUTION:In a state that input data is brought to band limit and set to instantaneous frequency information by a base band digital signal processing part 1-4, data of an offset frequency corresponding to a center frequency of a channel is added, and signals of different center frequencies are generated in advance in a base band zone. Subsequently, they are added in the base band zone, and thereafter, modulated. In such a way, a multi-carrier frequency can be generated in one orthogonal modulator 1-13, and also, by varying the data of the offset frequency, the signals of different center frequencies can be generated, and since the synthesis in an RF zone is not executed, the generation of cross modulation and spuriousness is prevented. |
