Multi-band radio terminal apparatus

A multi-band radio terminal apparatus comprising:

• transmitting/receiving means for processing radio communication signals of a plurality of communication frequency bands, said radio communication signals being used to communicate with a base station;
• first frequency converting means for frequency-converting the frequency bands of said radio communication signals between the communication frequency bands and an intermediate frequency band;
• and
• second frequency converting means for converting said radio communication signals between base-band signals and an intermediate frequency signal;
• wherein:
• said first frequency converting means includes;
• one reception-sided mixer for converting a reception signal within the communication frequency band 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 band;
• and
• a first single local oscillator for commonly supplying a local oscillator signal to both said reception-sided mixer and said transmission-sided mixer;
• and
• said first local oscillator includes:
• switching means for commonly supplying an oscillator output of an oscillator to both said reception-sided mixer and said transmission-sided mixer while maintaining a frequency of said oscillator output, or for either doubling or frequency-dividing the frequency of said oscillator output to commonly supply said oscillator output having either the doubled frequency or the frequency-divided frequency to both said reception-sided mixer and said transmission-sided mixer 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.