Patent ID: 7403580
Filing Date: 2008-07-22
Classification: H04L

Abstract:
1. A radio communication device conforming to plural communication protocols which performs communications with signals having different signal bandwidths, comprising: an RF unit that performs transmission and reception of a radio signal, a signal processing unit, a sampling unit connected between the RF unit and the signal processing unit which performs A/D conversion to a reception signal inputted from the RF unit and outputted to the signal processing unit and D/A conversion to a transmission signal inputted from the signal processing unit and outputted to the RF unit, and a control unit that controls the sampling unit, wherein the sampling unit includes: an anti-alias filter that performs filtering to the signals having signal bandwidths of the plural communication protocols by one cutoff frequency, an A/D converter and a D/A converter that perform A/D conversion and D/A conversion with suitable sampling frequencies for each of the communication protocols, a reception rate converter, a transmission rate converter, and a clock supply unit that supplies clocks to the A/D converter, the reception rate converter-6, the D/A converter, and the transmission rate converter on the basis of notification from the control unit, the cutoff frequency of the anti-alias filter is set not lower than the maximum signal bandwidth of the plural communication protocols, the A/D converter and the D/A converter sample the transmission signal and the reception signal with a sampling frequency not lower than double the cutoff frequency, the reception rate converter outputs to the signal processing unit a signal having an output signal from the A/D converter decimated by a decimating rate determined on the basis of a relation between each of the signal bandwidths of the communication protocols and the sampling frequency, the transmission rate converter outputs an input signal to the D/A converter while interpolating the transmission signal inputted from the signal processing unit by an interpolating rate determined on the basis of a relation between each of the signal bandwidths of the communication protocols and the sampling frequency, and the clock supply unit supplies a first clock conforming to the sampling frequency to the A/D converter and the D/A converter, and supplies a second clock conforming to the decimating rate and the interpolating rate to the reception rate converter and the transmission rate converter.