A baseband filter unit inputs a received signal including a sine wave at least in a portion of the received signal. A differentiator differentiates the received signal. A first correlator correlates the received signal differentiated and a cosine waveform. An acquisition unit acquires a value of the received signal as an offset value, at a time estimated based on a result of correlation in the first correlator and at a time when the received signal includes a sine waveform. A correction unit corrects the received signal in accordance with the offset value acquired in the acquisition unit.
