Flexible Baseband Analog Circuits for Software-Defined Radio Front-Ends

This thesis presents an approach to design a digitally programmable low pass filter intended for a software-defined radio (SDR) front-end. To obtain high-order filtering, we exploit a cascade of single-amplifier biquadratic sections, namely active-Gm-RC and Rauch. These cells combine the advantage of Gm-C filters (no parasitic poles) with the advantages of Active-RC filter (large linear range). Furthermore, they provide digitally programmable bandwidth and power consumption with a fully customizable cut-off frequencies range.he realized chips in this work can be generally divided into two categories to their technology. One is realized in 0.18um CMOS technology with 1.8-V supply voltage and the other is realized in 90nm CMOS technology with 1.2-V supply voltage.he 0.18um LPF provides a frequency tuning range between 0.54MHz and 15.71MHz with noise level between 47.9nV/Hz and 186nV/Hz whereby the power consumption conveniently varies from 0.69mW to 21.6mW. The die area is 1.43 * 1.42 mm2. he 90nm LPF provides a frequency tuning range between 0.13MHz and 30MHz with noise level between 87nV/Hz whereby the power consumption conveniently varies from 0.83mW to 25.73mW. The die area is 1.3 * 1.2 mm2.