RADIO COMMUNICATION EQUIPMENT AND INTEGRATED CIRCUIT USED THEREFOR

摘要

PROBLEM TO BE SOLVED: To minimize complexity in the internal frequency configuration of equipment and increase in the number of parts caused by the complexity. SOLUTION: In this multiband/multimode radio communication equipment, the oscillation frequency of an RF local synthesizer 17 is used, by changing a frequency dividing ratio corresponding to a communication mode through a variable frequency divider 22. A reception intermediate frequency is equalized in respective communication bands, and in the case of the same modulating system, a reception IF filter 5 and a reception intermediate frequency variable gain amplifier 6 are used in common. Moreover, the oscillation frequency of a local synthesizer 20 for quadrature modulation is used by changing the frequency dividing ratio corresponding to the communication mode as well. Furthermore, a transmission intermediate frequency variable gain amplifier 12 and a transmission intermediate frequency filter 13 are used in common at different transmission intermediate frequencies in respective communication bands.