Patent ID: 7058380

Claim:
A multi-band radio signal transmitter/receiver capable of carrying out a communication through a signal of a first communication method of transmitting/receiving a signal modulated by using information with regard only to a phase and through a signal of a second communication method of transmitting/receiving a signal modulated by using information with regard to a phase and an amplitude and can also carry out a communication in a plurality of different frequency bands, characterized by including: first frequency signal generating means for generating a signal of a fixed frequency that is different between a time of said first communication method and a time of said second communication method; second frequency signal generating means for generating a signal of a frequency corresponding to a communication channel to be used, with regard to a communication method and a frequency band that are selected from said first communication method, said second communication method and said plurality of frequency bands, wherein said signal is a transmitting/receiving reference oscillation signal that is used to generate a local oscillation signal for demodulating a reception signal based on said first communication method or a reception signal based on said second communication method for each communication method and is also used to generate a transmission signal based on said first communication method or a transmission signal based on said second communication method; first communication method modulating means for generating a modulation signal in which a transmitting baseband signal is modulated by using a signal of a fixed frequency for said first communication method from said first frequency signal generating means, as a modulating reference signal, when the transmission signal of said first communication method is generated; amplifying means for amplifying a signal of a fixed frequency for said second communication method from said first frequency signal generating means, when the transmission signal of said second communication method is generated; and transmitting signal generating means for generating a modulating reference signal, which when generating the transmission signal of said first communication method, phase-compares said modulation signal from said first communication method modulating means with said transmitting/receiving reference oscillation signal from said second frequency signal generating means, controls a variable frequency oscillator based on its phase comparison output and thereby generates a modulation transmission signal, and when generating the transmission signal of said second communication method, phase-compares said amplified signal of the fixed frequency for said second communication method from said amplifying means with said transmitting/receiving reference oscillation signal from said second frequency signal generating means, and based on its phase comparison output, generates a modulation signal of said second communication method.