Patent ID: 8532162

Claim:
A digital front end transceiver system for a software radio system comprising: a transmitter module adapted to digitally interpolate, up-convert and combine baseband digital in-phase (I) and quadrature (Q) channels to form a digital intermediate frequency (IF) IQ signal for conversion to an analogue IF IQ signal for transmission; and a receiver module adapted to separate, down-convert and decimate a received digital IF IQ signal into baseband digital I and Q channels, wherein the transmitter and receiver modules use a common fixed sampling and IF conversion rate f s , where f s is a quadruple of the bandwidth of the baseband signal, such that the system can be applied in a software radio system for a wireless communication application having any baseband bandwidth by selecting the fixed sampling rate based on the baseband bandwidth, wherein the sampling rate f s =4 BW where BW is the bandwidth of the baseband signal, such that the center frequency f IF of the intermediate frequency signal IF is f IF =BW, and wherein the receiver module includes a down-converting digital IF sampler/mixer having a numerically controlled oscillator (NCO) and two sign converters for separating and down-converting from an intermediate frequency to a baseband the a digital IQ signal received from a digital to analogue converter and separating the signal into the respective I and Q signal components, and a decimator having, for each of the I and Q signals, a low pass filter for pulse shaping and decimating and a sampler for down-sampling the I and Q channel signals to reduce the signal bandwidth to that of the a desired digital baseband, wherein the NCO and two sign converters are implemented using two four input multiplexers and a 2 bit counter wherein the sign change mechanism uses 2's complement sign inversion performed by an inverter and one bit adder.