Mixed-domain receiver architecture for white space software-defined radio scenarios

For emerging Software-Defined Radio systems to be prepared to deal with wide-band sparse spectrum signals, its analog-to-digital front-end must be developed to exhibit advanced features in terms of high sampling rate and large dynamic range. Within this context, the use of sophisticated mixed-analog/digital-domain implementations for the receivers can be advantageous. In this work, a novel approach of Hybrid Filter Bank (HFB) is devised for this application, its core element being an original eight-channel multiplexer covering the 1.3-1.7-GHz frequency band. Furthermore, its digital filter bank can be synthesized to compensate some imperfections coming from the RF analog multiplexer. This makes the HFB a system with flat frequency response in magnitude and linear phase. For validation, the inversion of the channel transfer functions of a measured multiplexer by applying a digital reconstruction filter bank properly designed is proven.