Patent ID: 8897346

Claim:
A modem device comprising: a modulation circuit configured to modulate a transmission signal and to generate a modulated signal; a frequency conversion circuit configured to convert a frequency of an external input signal and to generate an intermediate frequency signal, the external input signal being input from an external device; a demodulation circuit configured to demodulate the modulated signal or the intermediate frequency signal and to generate a reception signal; and an adjustment circuit configured to adjust amplitude of the transmission signal based on the reception signal, wherein in a communication mode for communicating with the external device, the modulation circuit is configured to output a first modulated signal to the external device, the first modulated signal being generated using the first frequency set at the time of output to the external device, the frequency conversion circuit is configured to convert a second frequency set to the external input signal into the intermediate frequency signal with a third frequency, and the demodulation circuit is configured to demodulate the intermediate frequency signal and to generate a first reception signal, and in an adjustment mode for adjusting the amplitude of the transmission signal, the modulation circuit is configured to output a second modulated signal generated using the third frequency to the demodulation circuit without passing the second modulated signal through the frequency conversion circuit, the demodulation circuit is configured to demodulate the second modulated signal and generates to generate a second reception signal, and the adjustment circuit is configured to adjust the amplitude of the transmission signal based on the second reception signal.