Patent ID: 8010046

Claim:
A wireless communication apparatus for demodulating modulated information which is transmitted from a wireless tag so as to read out the modulated information, comprising: an antenna which transmits a transmission signal to the wireless tag and receives a signal transmitted from the wireless tag as a reception signal; a demodulator which demodulates the reception signal to output a demodulated signal; a signal outputter which outputs a proportional signal proportional to the transmission signal; and a controller which calculates the proportional signal and the demodulated signal to output a calculated signal, and calculates the calculated signal and the reception signal, wherein the controller includes an attenuator which calculates a signal level of the proportional signal and the demodulated signal, wherein the demodulator comprises a quadrature demodulator which divides the reception signal into two signals which differ in phase by 90 degrees to each other to demodulate the two signals, and wherein the attenuator includes a quadrature modulator which divides the proportional signal into two signals which differ in phase by 90 degrees to each other, and multiplies the two signals divided by the quadrature modulator by the two signals demodulated by the quadrature demodulator, respectively.