To readily and fully prolong a communication range of an existing reader/writer by using a signal processing apparatus that is readily mountable to the existing reader/writer.
In the signal processing apparatus, a first carrier wave modulated with a first piece of piece of data transmitted from the reader/writer to a noncontact communication device is received by means of a first antenna; a second carrier wave is generated by amplifying the first carrier wave, the second carrier wave is modulated with the first data; the second carrier wave modulated with the first piece of data is transmitted to the noncontact communication device by means of a second antenna; second piece of data returned from the noncontact communication device by load modulation of an antenna in the noncontact communication device are received by means of the second antenna; and the second piece of data is transmitted to the reader/writer by performing load modulation changing an impedance of the first antenna based on the second data.
Tetsuo Kanamoto
Koji Hagiwara
Kazuki Matsumoto