Patent ID: 8050365

Claim:
A radio communication device configured to perform baseband processing by subjecting a received signal to an analog to digital (AD) conversion at a predetermined sampling frequency and converting a digital signal resulting from the AD conversion into a baseband signal by frequency conversion, said radio communication device comprising: a signal allocating unit configured to allocate signals to an I-channel and a Q-channel; a frequency converting unit configured to convert the digital signal resulting from the AD conversion into a complex baseband signal at a frequency f 2 having a relation such that a ratio of the sampling frequency F s at a time of the AD conversion to the frequency f 2 is one of a ratio of 4 to 1 and a ratio of 4 to 3, by sequentially multiplying each sample of the allocated samples by coefficients of 1 and −1 in each of the I-channels and the Q-channels; a waveform shaping unit configured to subject the baseband signal to waveform shaping; and a down-sampling unit configured to subject the baseband signal to sample discrete reduction taking one sample in N/2 samples, using a relation such that a ratio of a band occupied by the baseband signal to the sampling frequency F s is 1 to N, where N is an even number of two or more.