Abstract: A receiver supporting a plurality of radio communication systems having different specifications includes a setting unit, a clock generation circuit, a voltage-current conversion amplifier, a switch, integrators, an AD conversion circuit, and a feedback circuit. The setting unit sets a value suitable for a carrier frequency used in one selected radio communication system. The clock generation circuit generates a first clock having a first frequency and a second clock having a second frequency. The conversion amplifier converts an input voltage signal into a current signal. The switch switches between connection and disconnection modes in accordance with the first clock to output the current signal. Each integrator operates in accordance with the second clock and includes two or more switched capacitor circuits and an operational amplifier. The AD conversion circuit converts a signal supplied from the preceding integrator into digital form. The feedback circuit operates in accordance with the second clock.

Abstract: A receiver apparatus includes a plurality of signal receiving means; a plurality of channel signal outputting means for sampling signals received by the plurality of signal receiving means at sampling rates switched within a predetermined range or between multiple values and outputting channel signals; control means for controlling the sampling rates in the plurality of channel signal outputting means; response estimating means for estimating responses on the basis of the channel signals output from the plurality of channel signal outputting means; evaluating means for evaluating reception characteristics on the basis of the responses estimated by the response estimating means; and determining means for determining the sampling rates in the plurality of channel signal outputting means on the basis of the reception characteristics at the multiple sampling rates evaluated by the evaluating means.

Abstract: A wireless communication apparatus for receiving a packet formed of a signal modulated by OFDM includes the following elements. A band-pass filter extracts an OFDM signal of a desired band. A low-noise amplifier having a gain controlled according to a received-signal intensity amplifies the desired OFDM signal. A frequency converter down-converts the amplified OFDM signal into a baseband signal. An analog-digital converter converts the baseband signal into a digital signal. A first high-pass filter removes a DC offset from the baseband signal corresponding to a predetermined preamble portion of the packet. A frequency-offset estimator estimates a frequency offset from the sample signals constituting the baseband signal from which the DC offset has been removed by the first high-pass filter. A frequency-offset corrector removes the estimated frequency offset from the baseband signal.

Abstract: A receiving device including channel signal output means for sampling a received signal at a sampling rate switched one of in a predetermined range and between a plurality of values and outputting a channel signal, control means for controlling the sampling rate in the channel signal output means, response estimation means for estimating a response based on the channel signal output by the channel signal output means, evaluation means for evaluating a reception characteristic based on an estimation result of the response by the response estimation means, and determination means for determining the sampling rate in the channel signal output means based on an evaluation of the reception characteristic at a plurality of sampling rates by the evaluation means.