ADC systems for SDR digital front-end

This paper describes the various issues related to the analog-to-digital (A-D) conversion process performed in a software defined radio (SDR). An architecture that may be suitable for the digital front end of a multiband, multimode SDR is proposed. Implementation considerations based on current analog-to-digital converter (ADC) technologies are discussed, together with digital signal processing techniques that can be applied to enhance the A-D process. Combination of time-interleaved ADCs with multirate polyphase filters banks to perform the channelization while reducing the matching difficulties encountered in time-interleaved ADC systems is also suggested.