Radio apparatus and transmission/reception method

A radio apparatus comprising:

• a common frequency synthesizer that generates a first frequency signal of a frequency of a combination of a transmission frequency and a reception frequency;
• a reception frequency synthesizer that generates a second frequency signal of a different frequency than that of the first frequency signal and that operates only in receiving a signal of a different frequency than that of the first frequency signal;
• a transmission mixer that combines the first frequency signal with a quadrature modulated I signal and a quadrature modulated Q signal for each transmission;
• a reception mixer that combines a received signal with the first frequency signal or the second frequency signal;
• a switch that connects said common frequency synthesizer and said reception mixer, while connecting said reception frequency synthesizer and said reception mixer only in receiving the signal of a different frequency than that of the first frequency signal;
• and
• a first symbol inverter that inverts a symbol of Q data obtained by subjecting a signal combined in the reception mixer to quadrature demodulation and then to A/D conversion.

A communication terminal apparatus having a radio apparatus, said radio apparatus comprising:

• a common frequency synthesizer that generates a first frequency signal of a frequency of a combination of a transmission frequency and a reception frequency;
• a reception frequency synthesizer that generates a second frequency signal of a different frequency than that of the first frequency signal and that operates only in receiving a signal of a different frequency than that of the first frequency signal;
• a transmission mixer that combines the first frequency signal with a quadrature modulated I signal and a quadrature modulated Q signal for each transmission;
• a reception mixer that combines a received signal with the first frequency signal or the second frequency signal;
• a switch that connects said common frequency synthesizer and said reception mixer, while connecting said reception frequency synthesizer and said reception mixer only in receiving the signal of a different frequency than that of the first frequency signal;
• and
• a symbol inverter that inverts a symbol of Q data obtained by subjecting a signal combined in the reception mixer to quadrature demodulation and then to A/D conversion.

A transmission/reception method comprising:

• at a time of ordinary reception, combining a first frequency signal with a quadrature modulated I signal and a quadrature modulated Q signal in a transmission mixer, said first frequency signal being generated in a common frequency synthesizer and having a frequency of a combination of a transmission frequency and a reception frequency, and combining the first frequency signal with a received signal in a reception mixer;
• at a time of receiving a signal of a different frequency than that of said first frequency signal, operating the common frequency synthesizer to generate a second frequency signal of a different frequency than that of the first frequency signal, and operating the transmission mixer to combine the second frequency signal with a received signal in said reception mixer;
• and
• inverting a symbol of Q data obtained by subjecting the received signal combined with the first frequency signal or the second frequency signal to quadrature demodulation and then to A/D conversion.