Patent ID: 6850739

Claim:
A multi-band radio terminal apparatus comprising: a transmitter/receiver for processing radio communication signals of a plurality of communication frequency bands, said radio communication signals being used to communicate with a base station; a first frequency converter for frequency-converting the frequency bands of said radio communication signals between the communication frequency bands and an intermediate frequency band; a second frequency converter for converting said radio communication signals between base-band signals and an intermediate frequency signal; and a base-band signal processing circuit for handling a conversion between said base-band signals and audio signals, wherein said second frequency converter includes a second local oscillator for producing a second local oscillator signal, and a mixer for using said second local oscillator signal so as to convert a transmission base-band signal into a transmission intermediate frequency signal, wherein said first frequency converter includes: one reception-sided mixer for converting a reception signal within the communication frequency bands into another reception signal within the intermediate frequency band, one transmission-sided mixer for converting a transmission signal within the intermediate frequency band into another transmission signal within the communication frequency bands, and a first local oscillator for commonly supplying a first local oscillator signal to both said reception-sided mixer and said transmission-sided mixer, wherein said second local oscillator outputs a plurality of oscillating frequencies in response to the frequency band of the radio signal used in the communication between the base station and the multi-band radio terminal apparatus.