| 摘要 |
PROBLEM TO BE SOLVED: To transmit a transmission signal in which a plurality of frequency bands exist without increasing the number of filters or without providing a changeover switch for the filters. SOLUTION: Based upon the frequency band of the transmission signal, the generation frequency band of a first IF signal to be generated by a digital signal modulator 11a is adjusted to be matched with an upper frequency edge of a first IF band pass filter 14. Further, the oscillation frequency of a first local oscillator 24a is adjusted to match a second IF signal resulting from the conversion of the first IF signal by a first frequency converter 23a with a lower frequency edge of a second IF band pass filter 25. COPYRIGHT: (C)2004,JPO |
